Thursday Podium Presentations
Compression Garments Can Be Worn During Trans-American Travel to Reduce Muscle Damage and Performance Decrements Following Sports Activity
D. Hooper,1 P. Secola,2 L. Dulkis,2 W. DuPont,1 C. Saenz,1 B. Kupchak,2 T. Szivak,1 B. Comstock,2 S. Flanagan,1 H. Luk,3 T. Beaudette,4 A. Galpin,5 C. Maresh,1 L. Brown,5 and W. Kraemer1
1The Ohio State University; 2University of Connecticut; 3University of North TX; 4California State University Fullerton; and 5California State University, Fullerton
Compression garments have been shown to enhance recovery when worn following demanding physical activity, which has been proposed to be due to the enhanced blood flow associated with the pressure against the skin. In the context of athletic performance for collegiate and professional sporting events that precede a trans-American flight, an extra stressor to blood flow is added in the form of reduced leg room and physical activity due to the constraints of airplane travel. Purpose: The purpose of this study was to assess whether situations where compression garments aid the recovery process could be extended to the context of a trans-American flight immediately following a sporting event, and whether the compression garments could attenuate muscle damage as well as performance decrements. Methods: Nineteen recreationally active men matched for Ponderel Index and body fat percentage were divided into either a compression group (COMP) (age: 23.1 ± 2.4 years, height: 174.8 ± 5.3 cm, weight: 84.96 ± 10.16 kg, body fat: 15.3 ± 6.0%) or control group (CONT) (age: 23.2 ± 2.3 years, height: 177.5 ± 6.3 cm, weight: 84.35 ± 8.99 kg, body fat: 15.1 ± 6.4%). Subjects in the COMP group wore the full body garment throughout the duration of the study, except during testing and the simulated sporting event. Subjects flew directly from Hartford, CT to Los Angeles, CA one day prior to participating in a muscle damage protocol designed to simulate a sporting event. On the day preceding travel, baseline measurements (day 1) for myoglobin (MYO), creatine kinase (CK) and countermovement jump (CMJ) were taken. This test battery was repeated on arrival to CA (day 2), immediately following the simulated sporting event (day 3), immediately following arrival back in CT (day 4) and again the following day (day 5). Results: In both the COMP and CONT group, MYO was significantly elevated immediately following the simulated sporting event (day 3). However, the COMP group demonstrated significantly (p ≤ 0.05) lower MYO concentrations (COMP: 9.68 ± 2.62 vs. CONT: 11.73 ± 3.93 nmol·L−1). Both groups also demonstrated significantly elevated CK values at all time points following the simulated sporting event (days 3–5). Again, the COMP group demonstrated significantly (p ≤ 0.05) lower CK values at each of these time points (day 3: COMP: 217.90 ± 46.90 vs. CONT: 282.13 ± 116.43 IU·L−1; day 4: vs. COMP: 535.50 ± 103.69 vs. CONT: 685.56 ± 147.11 IU·L−1; day 5: COMP: 350.00 ± 145.40 vs. CONT: 508.00 ± 115.63 IU·L−1). CMJ was significantly (p ≤ 0.05) reduced in the CONT group at both day 4 and day 5. Furthermore, the COMP group demonstrated significantly (p ≤ 0.05) greater CMJ performance at day 4 and day 5 (day 4: COMP: 24.60 ± 2.50 vs. CONT 22.50 ± 2.20 inches; day 5: COMP: 25.10 ± 3.89 vs. 23.80 ± 2.51 inches). Conclusions: Full body compression garments can be effective at reducing markers of muscle damage as well attenuations in athletic performance induced by a simulated sporting event that is followed by a trans-American flight for several days. Practical Applications: For athletes that have substantial travel periods immediately following sporting events, such as the schedules imposed by NCAA regulations in collegiate sports as well as the demanding professional sports schedules, full body compression garments can be worn to aid the recovery process from muscle damage which can also translate to improved performance.
The Influence of Exercise-Induced Hormonal Elevations on Muscle Growth in Resistance-Trained Men
G. Mangine,1 J. Hoffman,2 A. Gonzalez,2 J. Townsend,2 A. Wells,2 A. Jajtner,2 K. Beyer,2 C. Boone,2 R. Wang,2 A. Miramonti,2 M. La Monica,2 D. Fukuda,2 E. Witta,2 N. Ratamess,3 and J. Stout2
1Univ Central Florida; 2University of Central Florida; and 3The College of New Jersey
The hormonal influence on muscle growth is difficult to assess using traditional parametric statistical procedures due to response variations that may occur over the course of training. Partial least squares (PLS) structural equation modeling uses multiple linear regression analysis to assess the relationships between latent variables, which are the weighted sum of several measured manifest variables. Manifest variable groupings may either reflect (representative sample of all possible items) or form/cause the latent variable. Purpose: Examine relationships of the hormonal response to resistance exercise on measures of muscle growth in resistance-trained men. Methods: During the weeks prior (PRE) to and following (POST) 8-weeks of resistance training, ultrasound images were used to assess muscle thickness (MT) and cross-sectional area (CSA) in the vastus lateralis (VL) and rectus femoris (RF). Participants were randomly assigned to either a high volume (VOL, n = 13, 4 × 10–12 RM, 1 minute rest) or high intensity (INT, n = 14, 4 × 3–5 RM, 3 minutes rest) resistance training program. Blood samples were collected at baseline, immediately post, 30 minutes post, and 60 minutes post-exercise during week 1 (WK1) and week 8 (WK8) of the training program. Area under the curve analysis was used to describe the response to exercise for testosterone, growth hormone, insulin-like growth factor 1, cortisol, and insulin. The WK1 and WK8 responses were grouped to form latent variables for each hormone, while RF and VL measures (MT and CSA) were all grouped to reflect muscle size at PRE and POST, respectively. A consistent PLS algorithm was used to create structural model estimates between muscle size at PRE and the latent hormone variables, as well as between the latent hormone variables and muscle size at POST. Consistent bootstrapping using 500 samples was used to determine the statistical significance (p ≤ 0.05) of each pathway coefficient. Group-wise comparisons were made by dividing the file by group and rerunning the analysis. Statistical significance (p ≤ 0.05) was determined using independent t-tests. Results: The model was capable of explaining 75% (R2 ADJ = 0.690, p < 0.001) of the variance in muscle size at POST. A significant pathway was observed from muscle size at PRE to testosterone (p = 0.040), as well as from testosterone to muscle size at POST (p = 0.033). Although the predictive ability of the model improved (p < 0.001) when groups were split into INT (R 2 = 0.898; R2 ADJ = 0.835) and VOL (R 2 = 0.898; R2 ADJ = 0.825), no differences were found. Conclusions: Exercise-induced hormone elevations, testosterone in particular, appear to be related to muscle growth, independent of training volume or intensity. Practical Applications: The influence of exercise-induced hormone concentrations on skeletal muscle growth may be consistent across a broad range of training stimuli. Therefore, promoting high volume resistance training as being optimal for stimulating muscle growth, because it may induce a greater hormone response, does not appear to be appropriate.
Validity of Urine Specific Gravity when Compared to Plasma Osmolality as a Measure of Hydration Status in Male and Female NCAA Collegiate Athletes
L. Sommerfield, S. McAnulty, J. McBride, J. Zwetsloot, M. Austin, J. Mehlhorn, M. Calhoun, J. Young, T. Haines, and A. Utter
Appalachian State University
To date, there is conflicting evidence in the literature on the ability of urine specific gravity (Usg) and urine osmolality (Uosm) to detect hydration status when compared to plasma osmolality (Posm) in both male and female athletes undergoing dehydration. Purpose: The purpose of this study was to evaluate the response of Usg and Uosm when compared to Posm from euhydration to 3% dehydration and then a 2-hour rehydration period in male and female collegiate athletes. Methods: Fifty-six NCAA wrestlers (mean ± SEM); height 1.75 ± 0.01 m, age 19.3 ± 0.2 years, and body mass (BM) 78.1 ± 1.8 kg and 26 NCAA women's soccer athletes; height 1.64 ± 0.01 m, age 19.8 ± 0.3 years, and BM 62.2 ± 1.2 kg were evaluated. Hydration status was obtained by measuring changes in Posm, Uosm, Usg and BM. Results: Male and female subjects dehydrated to achieve an average BM loss of 2.9 ± 0.09% and 1.9 ± 0.03%, respectively. Using the medical diagnostic decision model, the sensitivity of Usg was high in both the hydrated and dehydrated state for males (92%) and females (80%). However, the specificity of Usg was low in both the hydrated and dehydrated states for males (10% and 6%, respectively) and females (29% and 40%, respectively). Significant main effects (p < 0.025) were found for Posm, Uosm, and Usg for males and Uosm and Usg for females. Posm for the males significantly increased from baseline to postdehydration (280.4 ± 2.2 to 288.1 ± 2.4 mosm per kilogram). The Usg significantly decreased below baseline at the 2-hour rehydration period for males and females respectively, (1.027 ± 0.001 to 1.021 ± 0.001 and 1.021 ± 0.001 to 1.011 ± 0.002). No significant correlations were found between Usg and Posm during either the hydrated or dehydrated state for males or females. Conclusions: Based on these results, the use of Usg as a field measure of hydration status in male and female collegiate athletes should be used with caution. Practical Applications: Considering that athletes deal with hydration status on a regular basis, the reported low specificity of Usg suggests that athletes could be incorrectly classified leading to the unnecessary loss of competition.
Comparison of Powerlifting Performance in Trained Males Using Traditional and Flexible Daily Undulating Periodization
R. Colquhoun, B. Campbell, C. Gai, J. Walters, A. Brannon, M. Kilpatrick, D. D'Agostino, P. Knutson, D. Bove, and J. Dolan
University of South Florida
Daily undulating periodization is a growing trend in the exercise science literature. Flexible daily undulating periodization allows for athletes to have some autonomy within a periodized training cycle and is a relatively new and unstudied concept. The comparison of a flexible and traditional daily undulating periodization program using trained males has not been examined in the literature. Purpose: The purpose of this study was to compare the effects of Flexible and Traditional Daily Undulating Periodization models on powerlifting performance in trained males. Methods: 25 resistance-trained males (23 ± 6 years; 79 ± 22 kg) completed a 9-week resistance-training program and were randomly assigned to one of 2 groups: Flexible Daily Undulating Periodization (FDUP; N = 14) or Daily Undulating Periodization (DUP; N = 11). All subjects possessed a minimum of 6 months of resistance training experience and were required to squat 125% their bodyweight, bench press their bodyweight, and deadlift 150% their bodyweight. Dependent variables (DV) included bench press 1RM, squat 1RM, deadlift 1RM, Powerlifting total, and Wilk's Coefficient. Each DV was assessed at baseline and after the 9-week training program. The DUP group performed a hypertrophy workout on Monday, a power workout on Wednesday, and a strength workout on Friday. The FDUP group completed the exact same workouts in a given week, but were allowed to choose the order of the workouts. Data for each DV were analyzed via a 2 × 2 between-within factorial repeated measures ANOVA. The alpha criterion for significance was set at 0.05. Results: There were no significant differences in total volume or intensity between groups. There was a main effect for time (p < 0.001) for 1RM Squat (FDUP pre = 132 ± 34 kg, FDUP Post = 148 ± 33 kg; DUP pre = 147 ± 31 kg, DUP post = 165 ± 25 kg), 1RM Bench Press (FDUP pre = 96 ± 20 kg, FDUP post = 102 ± 19 kg; DUP pre = 147 ± 31 kg, DUP post = 165 ± 25 kg), 1RM Deadlift (FDUP pre = 166 ± 41 kg, FDUP post: 181 ± 37 kg; DUP pre = 174 ± 25 kg, DUP post = 188 ± 29 kg), Powerlifting Total (FDUP pre = 394 ± 90 kg, FDUP post = 431 ± 84; DUP pre = 439 ± 71 kg, DUP post = 480 ± 69 kg), and Wilk's Coefficient (FDUP pre = 147 ± 25 kg, FDUP post = 304 ± 51; DUP pre = 299 ± 41, DUP post = 325 ± 38). There were no interaction effects between the FDUP and DUP for any of the variables assessed. Conclusions: Nine weeks of Flexible DUP leads to comparable gains in powerlifting performance when compared to a Traditional DUP program in trained males. This may be attributed to the fact that both groups performed similar volumes of work throughout the study. Specifically, FDUP improved squat 1RM by 12%, bench press 1RM by 7%, deadlift 1RM by 9%, powerlifting total by 9%, and Wilk's coefficient by 9%. Similarly, DUP improved squat 1RM by 12%, bench press 1RM by 8%, deadlift 1RM by 8%, powerlifting total by 9%, and Wilk's coefficient by 9%. Practical Applications: Flexible Daily Undulating Periodization is a viable option for producing maximal strength improvements in the powerlifts in trained males.
The Effect of Periodized Resistance Training on Maximal Strength Gains in Older Adults
J. Conlon, J. Tufano, A. Hopper, H. Banyard, L. Seitz, L. McQuoid, R. van Dordrecht, R. Newton, and G. Haff
Centre for Exercise and Sport Science Research, Edith Cowan University
Determining the optimal resistance training (RT) programme in aging individuals and the consequent impact on physical function is vital. Research has consistently highlighted the superiority of periodized RT for improving neuromuscular performance when compared to non-periodized RT across athletic populations. However, investigation into the application of periodized RT in older adults is scarce. Purpose: The purpose of this study was to compare two periodized models and non-periodized RT on maximal strength gains in older adults. Methods: Thirty-nine previously untrained older adults (70.49 ± 4.97 years; 72.89 ± 13.53 kg) were randomly stratified based on gender, strength and body mass index, into 3 training groups: non-periodized (NP), block periodization (BP) and daily undulating periodization (DUP). Subjects completed a RT intervention at a frequency of 3 days per week across 22 weeks. All groups used repetition maximum (RM) loads to ensure that the resistance stimulus was modified to accommodate strength adaptations. Furthermore, prescribed total repetitions were equal among groups, however the time and sequence of the load application was different. In detail, the NP group continually performed 10RM sets, the BP group cycled through 11 session training blocks of 15RM, 10RM and 5RM sets, and the DUP group completed a weekly cycle of 15RM, 10RM and 5RM sets across the three sessions. Finally, the same 6 exercises were performed every session targeting both concentric and eccentric muscle actions of major muscle groups. One repetition maximum (1RM) strength testing was performed for leg press and chest press exercises, pre-and post-intervention. Results: The group mean total for actual repetitions and volume load completed did not statistically differ between groups (p > 0.05). Changes in 1RM strength pre-to post-intervention are presented as group mean (±SD) percentage change (%Δ) values (Figure 1). A one-way ANOVA was used to assess any significant differences between groups (pNP p = 0.040; BP > DUP p = 0.014) and chest press strength (BP > NP p = 0.023; BP > DUP p = 0.008), with no differences between NP and DUP groups detected. Conclusions: In older adults, BP RT produces significantly greater %Δ in maximal strength gains when compared to NP and DUP training models. Practical Applications: When prescribing RT in aging populations, it is recommended to employ a BP model demonstrating progressive and structured increases in intensity over time for optimal strength adaptations. This model appears superior to NP, displaying no variation in the training stimulus (i.e., fixed repetition training), and DUP in which repetitions are altered at each training session throughout the week producing daily variation in the training stimulus.
Maximal Strength Training Improves Surfboard Sprint and Endurance Paddling Performance in Competitive and Recreational Surfers
J. Coyne,1 T. Tran,2 L. Lundgren,2 J. Secomb,2 R. Newton,3 and J. Sheppard4
1EXOS/Chinese Olympic Committee and Edith Cowan University; 2Surfing Australia and Edith Cowan University; 3Centre for Exercise and Sport Science Research, Edith Cowan University; and 4Surfing Australia
Competitive surfing requires a range of physical abilities for explosive wave-riding maneuvers and repeated bouts of sprint and endurance paddling. Sprint and endurance paddling ability impact competitive outcome and are a discriminator of surfing ability, and upper extremity (UE) strength has been to shown to have a very high correlation with faster paddling speeds. However there is no previous research examining the effects improving UE strength has on surfboard paddling ability. Purpose: This study aimed to investigate the effect of 5 weeks UE maximal strength training on surfboard sprint and endurance paddling. A secondary aim of this study was to analyze how initial UE strength levels influenced maximal strength trainings effects on surfboard paddling ability. Methods: Seventeen competitive (COMP) and recreational (REC) male surfers (29.7 ± 7.7 years, 177.4 ± 7.4 cm, 76.7 ± 9.9 kg) participated in the study. Anthropometry, 5 m, 10 m, 15 m sprint and 400 m endurance surfboard paddling tests along with pull up and dip 1RM strength tests were assessed pre and post intervention. Subjects in the TRAIN group performed maximal strength training in the pull up and dip using a 5/4/3/2/1 repetition protocol 3 days each week for 5 weeks, whilst a control (CONT) group did not perform resistance training. Each session was closely monitored and subjects incrementally added load from session to session. Differences between TRAIN and CONT groups were examined post intervention. Results: The TRAIN group increased their speed over the 5, 10 and 15 m while the control group became slower. The odds that these were substantial true differences were 87%, 74%, 87% over 5, 10, 15 m respectively with a moderate effect size for the 5 m (d = 0.71) and 10 m (d = 0.51) and small effect size (d = 0.4) for the 15 m. The TRAIN group also displayed faster endurance paddling performance compared to CONT (89% likelihood of substantial true difference, d = 0.72). In the TRAIN group, the weaker subjects increased sprint-paddling speed more so than stronger subjects (98%, 98% and 100% likelihood of substantial true difference; d = −1.05, −0.92, and −0.83 over 5, 10 and 15 m respectively). The weaker TRAIN subjects displayed improved endurance paddling performance compared to the stronger subjects (92% likelihood of substantial true difference; d = −0.62). Conclusions: Short-term exposure to maximal strength training elicits improvements in paddling performance measures. However, the magnitude of performance increases appears dependent on initial strength levels with differential responses between strong and weaker athletes. Practical Applications: Although a longer maximal strength training period may have produced more significant paddling improvements in stronger subjects, the nature of professional surfing means that practitioners are unlikely to have any more than 5 weeks in an uninterrupted block with athletes. This study appears to reveal a “threshold” level of maximal strength (1.2 relative 1RM Pull Up) that if possessed, there seems to be little improvement in paddling performance with short-term maximal strength training. As such, thorough investigations into the point this maximal strength “threshold” is reached for individual sports would be important to determine for strength and conditioning practitioners.
Effects of Cluster Sets on Acute Hypertrophic Variables and Fatigue During a High-Volume Squat Session
J. Tufano,1 J. Conlon,1 L. Bishop,2 B. Williamson,2 A. Hopper,2 L. Seitz,1 S. Nimphius,2 and G. Haff1
1Centre for Exercise and Sport Science Research, Edith Cowan University; and 2Edith Cowan University
Performing multiple repetitions in sequence results in a decrease in velocity. Hence, power training does not normally coincide with high-volume training. However, it may be possible to maintain repetition velocity during high-volume protocols by adding extra rest periods. Purpose: The purpose of this study was to determine the effects of cluster sets (CS) on total work (TW), concentric time under tension (TUT), peak concentric velocity (PV), and PV maintenance (PV%), expressed as a percentage of the initial repetition's PV. Methods: Twelve resistance trained men (26.00 ± 4.2 years; 83.06 ± 8.8 kg; 153.44 ± 18.4 kg 1RM; 1RM:body mass = 1.88:1) performed 3 sets of 12 back squat repetitions using 3 different set configurations: traditional sets (TRD) with 60% 1RM where all repetitions within a set were performed successively; cluster sets of 4 (CLU4) with 75% 1RM, inclusive of 30 seconds rest after the fourth and eighth repetition of each set; and cluster sets of 2 (CLU2) with 80% 1RM, inclusive of 30 seconds rest after the second, fourth, sixth, eighth, and 10th repetition of each set. Subjects were instructed to perform full squats (mean peak knee flexion 120.75 ± 12.41°) and were verbally encouraged to perform the eccentric phase under control and concentric phase as explosively as possible. Two minutes of seated rest were given between each set in all 3 protocols. A minimum of 48 hours was required between protocols, which were performed in random order. Force-time data were collected at 1,000 Hz. Results: Repeated measures ANOVAs (3 protocol × 3 set) were used to find significant differences (p ≤ 0.05). Main effects for protocol were found for TW and TUT with CLU2 > CLU4 > TRD, and for PV with CLU2 < CLU4 < TRD. Main effects for set were found for TUT with set 1 < set 2 < set 3, and for PV and PV% with set 1 > set 2 > set 3. No protocol × time interactions were present. Data are presented in Table 1. Conclusions: By utilizing cluster sets, subjects were able to use a greater load for a given number of repetitions without experiencing a greater decrease in velocity. Therefore, cluster sets allow for greater work to be performed while experiencing the same rate of velocity-assessed fatigue when compared to traditional sets using less load. Since hypertrophy is largely mediated by the amount of work performed and time under tension, the cluster set protocols used in this study may serve as alternative methods for stimulating hypertrophy while maintaining velocity when compared to traditional sets. Practical Applications: The correct usage of intra-set rest via cluster sets allows a lifter to utilize a greater training load for a given number of repetitions, resulting in greater mechanical work without a subsequent decrease in movement velocity. These data support the idea that cluster set loading may be beneficial during training with primary and secondary foci on hypertrophy and power, respectively.
Thursday Abstract Poster Presentations—Session A
Thursday, July 09, 2015, 11:30 AM–1:00 PM
Seasonal Analysis of Alteration in Salivary Immunoglobulin-A in Response to Physical Demands of Professional Australian Rules Footballers
S. Coad,1 A. Wellman,2 B. Gray,3 and C. McLellan3
1University of Michigan Athletics Department; 2University of Notre Dame; and 3Bond University
Elite Australian Rules Football (AFL) encompasses rigorous high-intensity movement characteristics, including running, accelerations, decelerations, jumping, landing, and collisions, which collectively contribute to athlete's experiencing post-match physiological and perceptual fatigue. The effect of weekly exposure to the physical stressors of AFL match-play requires a period of post-match recovery to allow for physiological restoration. Mucosal immunological markers can be considered a non-invasive indicator of recovery status from exercise, with alterations in secretion patterns indicative of autonomic nervous system imbalance, and can indicate periods of elevated risk of illness. Currently, longitudinal trends in post-match mucosal immunological function are poorly understood, and may augment our understanding of the seasonal effects of AFL match-play on athlete recovery time-frames. Purpose: To (a) assess seasonal variations in salivary immunoglobulin A concentration ([s-IgA]) measured at 36-hours (h) post-match throughout an AFL premiership season, and (b) assess the relationship between seasonal [s-IgA] trends and exercise loads throughout an AFL premiership season. Methods: Eighteen elite male AFL athletes (24 ± 4.2 years, 187.0 ± 7.1 cm, 87.0 ± 7.6 kg) were monitored for AFL match-play exercise loads and 36-h post-match [s-IgA] across 16 matches in 2014 AFL premiership season. Duplicate [s-IgA] measures were collected during a full rested and recovered stated, and were used as a baseline [s-IgA] for seasonal analysis. Throughout all AFL matches athletes were fitted with 10 Hz global positioning systems (GPS) with 100 Hz integrated tri-axial accelerometry (IA) devices (MinimaxX S5, Catapult Innovations, Scoreby, Australia) which calculated exercise loads (player load) during match-play. A linear mixed model analyses was conducted for time dependant changes in [s-IgA] and player load (PL). Post-hoc analysis and Cohen's effect size (ES) statistics were calculated for [s-IgA] compared a pre-season baseline, and for match-to-match variations in PL. Results: A significant main effect was found for longitudinal post-match [s-IgA] data (F (16, 240) = 3.78, p < 0.01) and PL data (F (16, 66) = 1.98, p = 0.03). Post-hoc analysis indicted 7 significant (p ≤ 0.05) post-match [s-IgA] differences compared to pre-season baseline [s-IgA], including post-matches 5 (−23.0%), 7 (−29%), 9 (−15.2%), 10 (−25.0%), 11 (−19.5%), 14 (−46.0%), and 15 (−27.6%). Further ES analysis indicated substantial decreases between pre-season baseline [s-IgA] and all post-match [s-IgA] from match 7 to 16 (decreases ranging from −15.2 to −46.0%). Post-hoc PL analysis revealed match-to-match significant differences (p ≤ 0.05) between matches 5 and 6 (7.0%), matches 6 and 7 (−8.2%), and matches 10 and 11 (−6.5%). Further match-to-match ES analysis of PL indicated substantial variation between matches, including matches 3 and 4 (−4.6%), 5 and 6 (7.0%), 6 and 7 (−8.2%), 7 and 8 (6.8%), and 10 and 11 (−6.5%). Conclusions: Throughout the course of an AFL premiership season 36-h post-match [s-IgA] was consistently, substantial suppressed compared to pre-season baseline concentration after match 7, which coincided with a 4 match period were PL was highly variable. The highly variable match-to-match PL, across matches 5 to 8, appeared to pre-empt and result in sustained suppression in post-match [s-IgA], and may be indicative of compromise mucosal immunological function or prolonged immunological recovery. Practical Applications: Based on results in the present study longitudinal monitoring of post-match [s-IgA] and AFL match-play PL can augment monitoring strategies aimed at detection of compromised immunological function. Further during periods of high variability in AFL match-play exercise loads, the present study's findings would indicate that sports scientists and performance staff should consider the likelihood of delayed immunological recovery beyond 36-h post-match.
The Effect of Alcohol Consumption after Heavy Resistance Exercise on Lipopolysaccharide-Stimulated IL-1β, TNF-α, and IL-10
D. Levitt,1 A. Duplanty,1 R. Budnar Jr,1 H. Luk,2 A. Fernandez,1 T. Layman,2 D. Fancher,2 B. McFarlin,2 D. Hill,1 and J. Vingren1
1Applied Physiology Laboratory, University of North Texas; and 2University of North Texas
The repair of muscle tissue following a bout of resistance exercise requires an inflammatory response, coordinated by cytokines including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-10. Independently of exercise, alcohol alters cytokine production and secretion by leukocytes in response to an inflammatory stimulus, lipopolysaccharide (LPS). No published research has investigated the effect of consuming alcohol after a bout of heavy resistance exercise on LPS-stimulated cytokine production. Purpose: The purpose of this study was to investigate the effect of alcohol consumption after an acute bout of heavy resistance exercise on LPS-stimulated production of IL-1β, TNF-α, and IL-10. Methods: Ten men (25.1 ± 3.1 years, 177 ± 7 cm, 83.8 ± 15.7 kg, 14.8 ± 8.5% body fat) and 8 women (22.6 ± 1.7 years, 161 ± 3 cm, 59.5 ± 6.0 kg, 26.5 ± 3.0% body fat) over the age of 21 years and recreationally resistance trained were recruited. Each participant completed 2 experimental exercise sessions consisting of heavy resistance exercise (6 sets of 10 repetitions of Smith machine back squats using a weight equal to 80% of each participant's pre-determined one-repetition maximum) followed by beverage consumption (alcohol condition or placebo condition). In the alcohol condition, participants received a dose equal to 1.09 g EtOH per kg lean body mass. Conditions were assigned in a randomized, counter-balanced manner. Blood samples were collected prior to exercise (PRE), 3 hours following exercise completion (+3), and 5 hours following exercise completion (+5) and stimulated with LPS. After a 24-hour incubation period (37° C, 5% CO2), supernatant was separated and analyzed for IL-1β, TNF-α, and IL-10. Data were analyzed using a 2-way, repeated measures ANOVA (condition × time). Results: A main effect of time was found for all analytes (p < 0.01). Post-hoc pairwise comparisons indicated that LPS-stimulated IL-1β concentrations increased at +5 compared to PRE and +3 (PRE: 993 ± 698 pg·mL−1, +3: 1,001 ± 552 pg·mL−1, +5: 1,694 ± 771 pg·mL−1); LPS-stimulated TNF-α concentrations increased at +5 compared to PRE and +3 (PRE: 2,747 ± 1,465 pg·mL−1, +3: 2,764 ± 1,356 pg·mL−1, +5: 6,404 ± 3,492 pg·mL−1); and LPS-stimulated IL-10 concentrations decreased at +3 compared to PRE and at +5 compared to +3 (PRE: 3,215 ± 2,062 pg·mL−1, +3: 2,244 ± 1,378 pg·mL−1, +5: 1,332 ± 1,038 pg·mL−1). LPS-stimulated concentrations of IL-1β, IL-10, and TNF-α did not differ between the alcohol and placebo conditions. Conclusions: Results indicated that consuming alcohol after a heavy resistance exercise bout does not affect the capacity of leukocytes to produce and secrete IL-1β, IL-10, and TNF-α in response to LPS, an inflammatory stimulus. In both conditions, leukocytes demonstrated increased pro-inflammatory responses 5 hours after heavy resistance exercise and decreased anti-inflammatory responses at both post-exercise time points (+3 and +5). Practical Applications: Although consuming alcohol following heavy resistance exercise does not affect the capacity of leukocytes to produce and secrete IL-1β, TNF-α, and IL-10 in the 5 hours after exercise, practitioners should be aware that alcohol might have other effects on the inflammatory response that were not investigated in this study.
Resistance Exercise Elicits Uric Acid Response in Men, but Not Women
A. Sterczala,1 S. Flanagan,2 D. Hooper,2 T. Szivak,2 W. DuPont,2 B. Comstock,3 and W. Kraemer2
1The University of Kansas; 2The Ohio State University; and 3University of South Dakota
Uric acid is a powerful antioxidant capable of reacting with free radicals, reducing oxidative stress and attenuating oxidative damage. At rest, women demonstrate significantly lower uric acid levels than men due in part to reduced renal reabsorption of urate. Numerous investigations have demonstrated uric acid increases following exercise in men; however, little information exists regarding potential sex differences. Purpose: The purpose of this investigation was to determine if resistance exercise induced increases in uric acid differ between trained men and women Methods: Ten resistance-trained men (mean ± SD; age = 23.6 ± 4.5 years; height = 176.3 ± 5.5 cm; weight = 86.0 ± 12.7 kg) and women (mean ± SD; age = 22.2 ± 2.3 years; height = 160 ± 4.7 cm; weight = 62.0 ± 8.5 kg) performed an acute heavy resistance exercise protocol (AHREP) consisting of 6 sets of 10 repetitions of the back squat. The load utilized began with approximately 75% of their back squat 1RM and was reduced as needed to complete the necessary repetitions. Rest periods of 2 minutes were given following sets 1 and 2, while rest periods of 3 minutes were given following sets 3, 4 and 5. Blood was collected via an indwelling cannula pre, immediately post and at 15, 30, 60 and 120 minutes post-AHREP. Blood was also collected at 24, 48 and 72 hours post-AHREP. Serum uric acid was measured in duplicate using commercially available uric acid reagents. Data were analyzed using a mixed methods repeated measures analysis of variance with pairwise comparisons made using Fisher's LSD. Results: Women demonstrated significantly lower uric acid levels than men at all time points measured. When compared with pre-AHREP values, men demonstrated significantly elevated uric acid levels at 60 and 120 minutes post-AHREP. No significant elevations in uric acid were observed in women. Conclusions: The results of this investigation demonstrate a sex difference in the uric acid response to resistance exercise. Following exercise, greater oxidative stress has been observed in men than women. These results suggest that the attenuated oxidative stress in women is not mediated by a greater increase in the antioxidant, uric acid. As uric acid is produced via degradation of purine nucleotides such as adenosine triphosphate, the reduced uric acid levels observed in women may demonstrate an attenuated metabolic stress. Lactate can inhibit renal clearance of urate, therefore the reduced lactate levels observed in women in this investigation may explain the differences in uric acid. Practical Applications: Uric acid can mitigate the oxidative stress induced by exercise. The lack of an observed uric response in women may suggest a reduced stress response to the AHREP. Differences in the stress response should be accounted for when implementing strength and conditioning programs.
MAPK Signaling in Response to Two Different Resistance Exercise Protocols in Human Skeletal Muscle
J. Townsend, J. Hoffman, A. Gonzalez, A. Jajtner, D. Church, D. Fukuda, and J. Stout
University of Central Florida
Mitogen activated protein kinase (MAPK) signaling pathways are known to contribute to skeletal muscle development and are activated by a variety of extracellular stimuli, including mechanical and metabolic stressors associated with resistance exercise. The MAPK is primarily made up of protein signaling modules in skeletal muscle which consist of extracellular signal-regulated kinases (ERK), ERK1/2, p38 MAPK; JNK, and transcription factor cJUN. However, it is unclear whether manipulating acute resistance exercise program variables alters the magnitude and duration of MAPK signaling. Purpose: The purpose of this study was to examine MAPK signaling following typical lower-body hypertrophy (HYP) and strength (STR) protocols. Methods: Ten resistance-trained men (90.1 ± 11.3 kg; 176.0 ± 4.9 cm; 24.7 ± 3.4 years; 14.1 ± 6.1% body fat) performed each protocol in a random, counterbalanced order separated by 1 week. The HYP protocol consisted of 6 lower body exercises at 70% of the 1 repetition max (1RM) and the STR protocol comprised the same lower body exercises at 90% of 1RM (Table 1). If the participant was unable to complete the desired number of repetitions, spotters provided assistance until the participant completed the remaining repetitions. Subsequently, the loads were adjusted so that participants were able to perform the specific repetitions for each set. Fine needle muscle biopsies were completed at baseline (BL) and 1 hour post exercise (1H). A multiplex signaling assay kit (EMD Millipore, Billerica, MA, USA) was used to quantify the phosphorylation status of proteins specific to the MAPK signaling pathway using MAGPIX (Luminex, Austin, TX, USA). Results: A 2-way ANOVA revealed that both training protocols elicited a significant time effect for cJUN (p = 0.025) and JNK (p = 0.05) between HYP and STR. Conclusions: It appears that HYP and STR resistance exercise protocols may not differentially activate MAPK signaling 1 hour post exercise. Practical Applications: Understanding the mechanisms involved in modulating skeletal muscle remodeling can enhance the development of resistance exercise protocols for optimal muscular and metabolic adaptations.
An Electromyographic Examination of Task Failure During a Sustained Submaximal Contraction for the Forearm Flexors
J. Carr,1 T. Beck,2 X. Ye,2 and N. Wages2
1University of Oklahoma; and 2The University of Oklahoma
When local muscle fatigue is induced with a sustained high-intensity isometric contraction, the primary factors driving the observed force loss are related to the changes that occur within the muscle. Therefore, by examining the progression of fatigue-induced task failure and the corresponding changes that occur within the electromyographic (EMG) signal, information regarding the relative contributions of muscle activation to task failure may be considered. Purpose: To examine the linearity of the EMG amplitude and frequency responses for the biceps brachii during a sustained constant-force isometric contraction to failure. Methods: Ten habitually active males (mean ± SD: age = 25.4 ± 3.7 years; height = 181.6 ± 4.8 cm; bodyweight = 90.9 ± 13.9 kg) volunteered for this study and went through a familiarization session before testing. During the testing visit, the subjects performed 3 maximal voluntary contractions (MVC) of the dominant forearm flexors, and the highest force value from the 3 trials was selected as the baseline MVC (MVCb). Then, with visual force-feedback displayed on a computer monitor, the subjects sustained 60% MVCb until fatigue-induced failure. EMG activity was detected from the biceps brachii with bipolar surface electrodes. The linearity of the EMG mean frequency and EMG amplitude versus time relationships were examined with linear regression models. Results: During the sustained 60% MVCb contraction, the EMG mean frequency decreased: (mean ± SD: slope = −0.83 ± 0.17 Hz·s−1; Y-intercept = 98.5 ± 14.9 Hz; r 2 = 0.88 ± 0.06). Whereas, the EMG amplitude increased: (mean ± SD: slope = 5.19 ± 3.10 μV·s−1; Y-intercept = 473.3 ± 302.5 μV; r 2 = 0.49 ± 0.19). Conclusions: The patterns of muscle activation during the fatiguing submaximal isometric contraction demonstrate that the decrease of the EMG mean frequency had greater linearity than the increase in EMG amplitude. Practical Applications: These findings illustrate the usefulness of EMG mean frequency for monitoring the progression of local muscle fatigue during sustained high-intensity contractions.
Thorstensson Test Data Analysis Method Affects Percent Fatigue Calculation
A. Ciccone, J. Deckert, T. Herda, P. Gallagher, and J. Weir
University of Kansas
Researchers have used repeated maximal-effort isokinetic knee extension tests to investigate neuromuscular characteristics since the 1970s. Although peak torque is consistently analyzed, (EMG) data analysis methodology for these tests is not consistent. As fatigue progresses, subjects generally take longer to reach isokinetic velocity. Thus, decreasing isokinetic load range with fatigue may affect reported torque and EMG variables. Purpose: Determine if there is a difference in EMG or torque data interpretation between three most common methods of analyzing torque and EMG during repeated maximal effort isokinetic knee extensions tests. Methods: Nine healthy males and 9 healthy females (age = 21.1 ± 1.4 years; height = 173.8 ± 12.4 cm; mass = 72.1 ± 14.7 kg) completed one bout of 50 repeated maximal effort concentric knee extensions at 180°·s−1 with passive flexion on an isokinetic dynamometer. Position, velocity, torque, and EMG data were sampled at 10 kHz for the duration of each test. Custom LabVIEW software was used to analyze peak torque (PT; same value regardless of analysis method), torque integral (TI), and EMG data in three different position windows based on range-of-motion (ROM): full concentric ROM (FUL), middle 30° ROM (MID), and isokinetic load range ROM (ISO). Percent change was calculated for peak torque, torque integral, vastus lateralis EMG amplitude, and peak torque to EMG ratio (PTEMG). Percent change was calculated by dividing the average difference between the first 3 repetitions and the last 3 repetitions by the average of the first 3 repetitions. TI and PT percent change data were analyzed using a 1 × 4 repeated measures ANOVA. EMG and PTEMG percent change data were analyzed using 1 × 3 repeated measures ANOVAs. Huynh-Feldt corrections were used when necessary. Alpha was set at 0.05. Results: There was a significant difference in fatigue percent change between analysis methods where PT (50.7 ± 11.6) was not different than TI FUL (49.2 ± 12.1), and both were less than TI MID (53.5 ± 11.6) and TI ISO (56.5 ± 10.9); TI ISO was greater than TI FUL, TI MID, and PT. There was no significant difference in EMG percent change between analysis methods (p = 0.228). There was no significant difference in PTEMG% difference between analysis methods (p = 0.308). Conclusions: The 3 most common position windows used to analyze EMG do yield consistent EMG amplitude percent change results but may result in different torque percent fatigue results. This is likely due to the change in isokinetic load range with fatigue. Practical Applications: Researchers should be aware that because isokinetic torque load range changes over a bout of repeated maximal-effort isokinetic knee extensions, the window from which torque data is collected can affect data interpretation.
Kinematic Properties of Slow Velocity and Traditional Velocity Resistance Training Sessions
P. Dietz,1 A. Fry,1 T. Herda,1 M. Andre,2 and M. Lane3
1University of Kansas; 2University of Wisconsin-La Crosse; and 3Eastern Kentucky University
Various methods of resistance training have gained in popularity such as super-slow resistance exercise (i.e., 10 seconds concentric and eccentric phases) where movement velocity is purposely slow. Because of the slow movement, there are limitations to the loads that can be lifted (e.g., <50% 1 RM). Purpose: The purpose of this study was to compare the biomechanical properties between purposely slow velocity (SLOW) and traditional resistance exercise (TRAD) that uses maximal or near-maximal lifting velocities. Methods: Healthy resistance-trained men (n = 5; X ± SD; age = 25.8 ± 3.3 years, height = 1.76 ± 0.07 m, weight = 92.7 ± 18.7 kg, 1RM bench press = 122.0 ± 29.1 kg, 1 RM squat = 165.0 ± 46.0 kg) performed 2 testing sessions in random-order; a SLOW session (1 set × 10 repetitions at 28% 1RM), and a TRAD session (3 × 10 at 70% 1 RM). Both sessions included the barbell parallel back squat and bench press exercise. A force plate and position transducer were used to collect kinetic and kinematic data for every repetition of both protocols. Data were collected at 1,000 Hz. Significance was set a priori (α = 0.05). Results: The table below lists the concentric data for several variables for both protocols for the squat and bench press exercises. For both the squat and bench press exercises, both concentric and eccentric mean force (N) and power (W) for each repetition was greater for TRAD (p ≤ 0.05). When the entire training session (squat + bench press) was examined, SLOW exhibited greater time under tension, while TRAD produced greater work (J) and impulse (N·s−1). Range of motion (ROM) was not significantly different between either protocol (p > 0.05). Conclusions: Contrary to suggestions in both the lay and scientific literature, purposely slow resistance exercise produced less force, power, and work than traditional velocity resistance exercise. This was expected since the velocities, and thus the accelerations were purposely kept low, resulting in lower values for force (mass × acceleration) and power (force × velocity). Additionally, due to the purposely slow velocity, considerably lower loads could be used, again contributing to the lower force and power. Practical Applications: Strength and conditioning professionals can use this information to help determine proper training methods when high levels of force, power, or mechanical work are important to the training effect. These data also help clarify the mechanical properties that purpose slow resistance exercise produce.
Effects of Velocity on Isometric Peak Torque, Electromyographic, and Mechanomyographic Responses to Repeated Maximal Eccentric Muscle Actions
E. Hill,1 C. Camic,2 T. Housh,1 M. Monaghan,2 K. Cochrane,1 C. Smith,1 N. Jenkins,1 J. Cramer,1 R. Schmidt,1 and G. Johnson3
1University of Nebraska-Lincoln; 2University of Wisconsin–La Crosse; and 3University of Nebraska–Lincoln
Purpose: The purpose of the present study was to examine the effects of repeated maximal eccentric muscle actions of the leg extensors on isometric peak torque, electromyographic, and mechanomyographic responses. Methods: Twelve resistance trained men (mean age ± SD = 24 ± 4 years; lower body resistance training = 9 ± 2 days per month) visited the lab on 3 occasions (separated by ≥ 72 hours) and performed 2 maximal voluntary isometric contractions (MVIC) before (pre) and after (post) performing 30 repeated maximal eccentric muscle actions of the dominant leg extensors on a calibrated isokinetic dynamometer at randomly ordered velocities of 60, 120, and 180°·s−1. Bipolar surface electromyographic (EMG) and mechanomyographic (MMG) signals were simultaneously recorded from the vastus medialis muscle. Separate 2 X 3 (Time [pre, post]) X (Velocity [60, 120, 180°·s−1]) repeated measures ANOVAs were used to analyze the isometric peak torque (PT), EMG amplitude (AMP), EMG mean power frequency (MPF), MMG AMP, and MMG MPF data. Results: There was a significant (p ≤ 0.05) interaction for isometric PT. Mean percent decreases in isometric PT were 17.9, 16.1, and 8.9% for 60, 120, and 180°·s−1, respectively. There were no significant interactions for any of the neuromuscular parameters, but significant main effects for time (marginal means collapsed across velocity) indicated that EMG AMP and MMG MPF decreased, MMG AMP increased, and EMG MPF remained unchanged (Table 1). Conclusions: The results of the present study indicated that isometric PT decreased after 30 repeated maximal eccentric muscle actions. The decreases in isometric PT coincided with decreases in muscle activation (EMG AMP) and global motor unit firing rate (MMG MPF), but action potential conduction velocity (EMG MPF) remained unchanged. These findings suggested that the fatigue-induced decreases in isometric PT and muscle activation were likely due to a decrease in global motor unit firing rate. The increase in MMG AMP, however, may have been due to a muscle-activation related decrease in muscle stiffness which allowed for greater oscillations of the activated muscle fibers. Practical Applications: The current study describes a potential neuromuscular mechanism that underlies eccentric fatigue-induced decreases in isometric PT. These findings provide the foundation for future studies to develop training or supplement-based interventions that coaches can use to reduce fatigue as a result of eccentric muscle actions.
Effect of Foot Position on Isometric Bench Press Performance
A. Pichardo, T. Erickson, M. Landram, J. Shah, and J. McBride
Appalachian State University
The bench press is a compound exercise commonly used to improve upper body strength. Previous investigations have analyzed kinetic and kinematic variables during different bench press variations. However, no known studies have examined the effect of foot position on force output and muscle activity. Purpose: The purpose of this investigation was to examine the effects of 3 different foot placements on isometric bench press force and muscle activity. Methods: Eleven recreationally trained males (age: 22.55 ± 1.04 years, height: 177.22 ± 7.56 cm, body mass: 85.43 ± 15.74 kg) participated in this investigation. Self-reported one-repetition maximum (1RM) of at least bodyweight was used as inclusion criteria (self-reported absolute 1RM: 117.79 ± 29.45 kg, relative 1RM: 1.37 ± 0.23). Subjects performed the isometric bench press with a normal foot placement with both feet on the ground (FD), both feet up on the edge of the bench (FU), and both feet out resting on an adjacent bench parallel to the ground (FO) in a randomized order. After 2 familiarization trials with FD placement, subjects performed 3 maximum voluntary isometric contractions for approximately 3 seconds each. Peak force (PF) and electromyography (EMG) were recorded for the pectoralis major (PM), anterior deltoid (AD), triceps brachii (TB), vastus lateralis (VL), biceps femoris (BF), and gastrocnemius (G) muscles. Results: PF output for FD, FU, and FO was 1,130 ± 281 N, 1,178 ± 247 N, and 1,128 ± 231 N, respectively. The average integrated EMG (avgIEMG) for the PM with the feet down, up, and out was 1.32 ± 0.51 mV, 1.23 ± 0.40 mV, and 1.30 ± 0.50 mV respectively. The avgIEMG for AD for feet down, up, and out was 2.91 ± 1.24 mV, 2.85 ± 1.23 mV, and 2.96 ± 1.19 mV, respectively. The avgIEMG for TB for feet down, up, and out was 2.34 ± 0.96 mV, 2.15 ± 0.78 mV, and 2.20 ± 0.92 mV, respectively. The avgIEMG for VL for feet up, down, and out was 0.23 ± 0.21 mV, 0.11 ± 0.01 mV, and 0.15 ± 0.09 mV, respectively. The avgIEMG for BF for feet down, up, and out was 0.22 ± 0.29 mV, 0.10 ± 0.04 mV, and 0.13 ± 0.07 mV, respectively. The avgIEMG for G for feet down, up, and out was 0.21 ± 0.09 mV, 0.23 ± 0.15 mV, and 0.20 ± 0.06 mV, respectively. A repeated measures general linear model returned no significant differences between conditions for force or muscle activity. Conclusions: Different foot positions do not have a significant effect on force production or muscle activity of upper and lower body musculature in isometric bench pressing. In this investigation the bar was attached to a rack which did not permit lateral or anterior/posterior motion of the bar. Thus, in a free weight bench press where these types of motion are possible, the results may be different. Practical Applications: Although force output and muscle activity was not significantly different between isometric conditions, stability may be increased with both feet on the ground during a dynamic movement. Further research is needed to determine the effect of differing foot positions on kinetic and kinematic variables with regards to dynamic bench press.
Quadriceps and Hamstrings Electrical Activity in Squats With Unrestricted vs. Restricted Leg Dorsiflexion
G. vonGaza, R. San Martin, L. Jean, and L. Chiu
University of Alberta
Restricting leg dorsiflexion to limit anterior translation of the leg's proximal aspect influences ankle, knee and hip mechanical effort. However, quadriceps and hamstrings activity during squat exercise performed with free versus restricted leg dorsiflexion has not been investigated. Purpose: To compare vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF) and biceps femoris (BF) activity between back squats with unrestricted (US) and restricted (RS) leg dorsiflexion. Methods: Four men and 4 women with at least 6 months experience squatting performed 2 sets of 3 repetitions for both US and RS at 80% of one repetition maximum US. A box placed in front of the toes was used to restrict leg dorsiflexion. Squat depth was defined as knee flexion angle which was determined from 3D motion analysis using 7 optoelectronic cameras sampling at 100 Hz. Bipolar surface EMG was recorded, bilaterally, from the VL, VM, RF and BF at 1,000 Hz. EMG data was digitally filtered and enveloped using a 100 m s root mean square. Left and right data were averaged. EMG data were averaged for 15° knee flexion intervals (i.e., 30–44°, 45–59°, etc.). EMG, reported in arbitrary units (AU), for the intervals where greatest eccentric and concentric squat depths occurred were compared. Integrated EMG (AU·s) was also determined for eccentric and concentric phases. Two-way (phase by type) ANOVA and Tukey post hoc were used for statistical comparisons. Results: There were no differences in VL (US: 71 ± 36 AU; RS: 72 ± 51 AU), VM (US: 80 ± 38 AU; RS: 75 ± 40 AU), RF (US: 49 ± 28 AU; RS: 41 ± 29 AU) and BF (US: 31 ± 20 AU; RS: 20 ± 8 AU) EMG at peak squat depth between US and RS. Concentric EMG at peak squat depth was higher than eccentric for VL (US: 85 ± 31 AU; RS: 58 ± 56 AU), VM (US: 91 ± 30 AU; RS: 64 ± 47 AU) and BF (US: 30 ± 12 AU; RS: 22 ± 15 AU), but not RF (US: 52 ± 21 AU; RS: 37 ± 36 AU). Concentric VL (US: 118 ± 74 AU·s−1; RS: 88 ± 69 AU·s−1), VM (US: 126 ± 38 AU·s−1; RS: 93 ± 45 AU·s−1) and RF (US: 75 ± 58 AU·s−1; RS: 44 ± 37 AU·s−1) integrated EMG were higher for US than RS. Eccentric integrated EMG was not different between US and RS for VL (US: 50 ± 26 AU·s−1; RS: 75 ± 55 AU·s−1) and RF (US: 39 ± 25 AU·s−1; RS: 39 ± 30 AU·s−1). Eccentric VM integrated EMG was greater in RS (79 ± 43 AU·s−1) than US (55 ± 26 AU·s−1). BF integrated EMG was not different between US (37 ± 17 AU·s−1) and RS (39 ± 16 AU·s−1). BF concentric (56 ± 25 AU·s) integrated EMG was higher than eccentric (20 ± 9 AU·s−1). Conclusions: Quadriceps activity was similar between US and RS at peak squat depth. However, total concentric VL, VM and RF activity, as inferred from integrated EMG, were greater in US. Neither BF activity at peak squat depth nor total BF activity were different between US and RS. These findings indicate US have greater quadriceps activity than RS; both squat types have similar BF activity. Moreover, the quadriceps and hamstrings are generally more active in the concentric versus eccentric phase. Practical Applications: Restricting leg dorsiflexion during squatting reduces quadriceps activity, which may impair the exercise's effectiveness. As BF activity is similar between squat types, US appear to better stimulate the thigh musculature. To optimize thigh muscle activation during squat exercise, maximum leg dorsiflexion is required, particularly in the concentric phase.
Comparisons of Shoulder Neuromuscular Responses in Three Different Groups of Elite Athletes
S. Kang,1 J. Hong,2 S. Kim,3 J. Chung,4 and J. Oh5
1Laboratory of Motor Control/Athletic Training, Kookmin University; 2Department of Physical education, Kookmin University; 3Korea Advanced Institute of Science and Technology; 4Korea National University of Transportation; and 5Korea Sport National University
Proprioceptive feedback provided by various joint mechanoreceptors is known to play an important role in stabilizing the shoulder joint. Different types of sport activities might have different effects on the neuromuscular control at the shoulder joint. No research has studied the effects of different types of overhead activities on joint position senses and muscular activation in elite athletes. Purpose: To compare shoulder neuromuscular responses of 3 different elite athletic groups and identify the difference of the neuromuscular responses. Methods: Forty-five athletes of 3 groups (shooting; 19.73 ± 1.22 years, n = 15, javelin; 20.53 ± 1.30 years, n = 15, handball; 19.33 ± 1.05 years, n = 15) participated in this study. To measure proprioceptive functions, AJPS, PJPS, TTDPM, onset latency and force reproduction were tested by isokinetic device and EMG. The data was analyzed by one-way ANOVA. Results: On shoulder ER, AJP error of javelin (4.87 ± 2.53°) and handball (5.16 ± 3.00°) were lower than shooting (8.60 ± 6.00°, p ≤ 0.05) and in PJPS, javelin (7.00 ± 3.67°) had lower error than shooting (11.69 ± 6.55°, p ≤ 0.05). In TTDPM, the error of handball (1.18 ± 0.57°, p < 0.001) on shoulder IR was higher than shooting (0.57 ± 0.32°) and javelin (0.44 ± 0.17°) and the angle of handball (1.27 ± 0.64°) on ER was also greater than shooting (0.58 ± 0.29°) and javelin (0.29 ± 0.13°, p < 0.001). In onset latency, on ER, javelin (0.16 ± 0.07 seconds, p < 0.01) and handball (0.09 ± 0.02 seconds, p < 0.001) were shorter than shooting (0.29 ± 0.17 seconds) in posterior deltoid. In infraspinatus, the response time in handball (0.11 ± 0.03 seconds) was shorter than javelin (0.17 ± 0.06 seconds) and shooting (0.25 ± 0.08 seconds) and then javelin had also faster onset time than shooting (p ≤ 0.05). On IR, the latency of handball was shorter than shooting in pectoralis major (0.11 ± 0.04 vs. 0.21 ± 0.07 seconds, p < 0.001) and latissimus dorsi (0.14 ± 0.04 vs. 0.31 ± 0.15 seconds, p < 0.001). The anterior deltoid onset of handball was also shorter than shooting (0.19 ± 0.06 vs. 0.29 ± 0.13 seconds, p < 0.01). The latency of javelin (0.22 ± 0.12 seconds, p ≤ 0.05) and handball (0.14 ± 0.04 seconds, p < 0.001) were shorter than shooting (0.31 ± 0.15 seconds) in latissimus dorsi. Conclusions: Javelin and handball athletes appeared to have lower JPS errors on shoulder ER and shorter onset latency than shooting players. Dynamic overhead activities were shown to be related to better joint position sense and muscular response. Practical Applications: Optimized neuromuscular control at the shoulder joint is closely related to better performance and lower injury risk. Proprioceptive or neuromuscular control facilitating training has been the focus of many strengthening and conditioning coaches. In designing such programs, sports specific activities and the level of overhead angle should be considered to effectively stimulate the proprioceptors around the shoulder joint and the level of intensity should be appropriately provided.
Effect of Imposing a Delay During Bench Press
M. Kenreich, B. Riemann, and G. Davies
Armstrong State University
The bench press (BP) is one of the most commonly utilized upper-body compound lifts. Numerous methods of performing the BP have been employed by strength and conditioning professionals. If performed in a rapid manner, the BP may be used to help train for explosive power. Additionally, a deliberate pause between the eccentric and concentric phases of the lift could reduce contributions of the stretch shorten cycle (SSC) and require greater relative contributions from contractile elements of the muscle. Purpose: The purpose of this investigation was to examine the effect of imposing various pause times between the eccentric and concentric actions of bench press. Additionally, because of muscle-tendon stiffness differences, this investigation aimed to determine if the effect of such pauses would be equal for men and women. Methods: Twenty physically active men (24.4 ± 1.3 years, 1.77 ± 0.05 m, 82.7 ± 7.3 kg) and 14 women (22.2 ± 2.99 years, 1.64 ± 0.06 m, 58.5 ± 6.39 kg) with 6 ≥ months resistance training experience completed a 1 repetition maximum (1RM) assessment. Following a rest period of 3–7 days, subjects performed 3 BP repetitions under each of 5 conditions: rebound (RBP, no pause), short pause (SPBP, 1.5 s), medium pause (MPBP, 3.0 s), long pause (LPBP, 4.5 s), and pure concentric (PCBP). Each of the lifts was performed at 75% 1RM with 2–3 minutes rest given between each lift. During each lift, a 12 camera motion analysis system recorded bar displacement. The kinematic data, along with the known mass of the bar, were used to compute the average peak power (PP) across the 3 trials for each condition. Results: The results of sex by pause-time condition analysis of variance revealed a significant interaction. Bonferonni post-hoc comparisons of the pause-times then revealed the RBP PP to be greater than all other pause-times (d = 0.90–1.28) and SPBP to be greater than MPBP and LPBP (d = 0.26–0.87) for the men. There was no significance differences in PP between the pause-times for the women. Conclusions: These results confirm a significant decline in PP development with increasing pause lengths for bench press lifts performed at 75% 1RM for men. The potential benefit of any pre-stretch movement appears to dissipate with delays exceeding 1.5 s. For women, no significant difference existed in PP production. The existence of effects for men, and lack thereof for women might be representative of different underlying traits between the sexes. Previous research indicated that men may exhibit greater muscle stiffness and so it is possible that muscle stiffness may partially explain the men's ability to greater utilize a pre-stretch, compared to the women. Practical Applications: The practical applications of these findings indicate that athletes may be able to perform in SSC type movements utilizing strain energy even with amortization phases of 1.5 s. Conversely, those wishing to increase the demands of contractile elements by eliminating SSC contributions should increase delays beyond 1.5 s for optimal results. Future research should examine the effect of shorter pause times given that no discernable difference in PP existed after a pause of 1.5 s. Shorter pause times may give a more precise idea of the rate of strain energy dissipation.
Kinetic Contributions of the Upper Limbs During Counter-Movement Vertical Jumps With and Without Arm Swing
E. Mosier,1 A. Fry,1 P. Moodie,2 and R. Moodie2
1University of Kansas; and 2Dynamic Athletics (DARI)
The vertical jump is a complex multi-joint action where musculature of the lower and upper extremities collectively summate forces to produce movement. What is not clear is what portion of the resulting ground reaction forces (GRF) are due to the arm swing action. Purpose: The purpose of this study was to determine the kinetic contributions of the upper extremities during a counter-movement vertical jump (CMVJ) while using arm swing (AS) or no-arm swing (NAS) conditions. Methods: Fourteen healthy, recreationally active men (age = 24.1 ± 3.9 years, height = 1.76 ± 0.05 m, weight = 82.6 ± 10.6 kg) volunteered for this investigation. Participants performed in random order a total of 6 jumps consisting of 3 AS and 3 NAS CMVJ. The AS began with the participants standing upright with arms fully raised above the head. The NAS began with the dominant upper limb fully raised overhead, while the non-dominant hand remained on the iliac crest during the entire CMVJ. All jumps were performed with maximal effort while reaching for a jump target suspended from the ceiling. Participants were instructed to descend to an internal knee angle of 90°. A 3 dimensional (3-D) markerless motion capture system (MCS; DARI, Lenexa, KS) was used to access and analyze the kinetic and kinematic data. Body segmental masses were determined from DEXA scans. Results for all participants were determined for each jump performed, with statistical analyses performed on mean values from all 3 jumps for each subject. Each jump was analyzed from the beginning of the descent to takeoff. Results were analyzed with t-tests (p ≤ 0.05). Results: Results for the AS and NAS CMVJ are shown in the table. Compared to the NAS, the significant increase in jump height for the AS was an average of 0.07 ± 0.03 m (3.0 ± 1.3 in). DEXA scans determined the upper limbs were 12% of the total body weight. Movement of the upper limbs produced 32.2 ± 7.0% of the mean GRF during the AS CMVJ, and only 11.3 ± 2.2% during the NAS CMVJ. Similar differences were observed when both the eccentric and concentric phases were separately analyzed. Conclusions: The enhancement of performance when jumping using an AS resulted in a 13% increase in jump height. The contribution of the arms averaged a total of 32% throughout the jump and 31% at the GRF peak before takeoff. The use of an arm swing during a CMVJ results in different GRF characteristics in comparison with a vertical jump without the use of the upper limbs. Thus, interpretation of the resulting GRF during a CMVJ with arm swing must consider that nearly a third of the forces are due to upper limb contributions. Practical Applications: The upper extremities can greatly influence vertical jump performances and the accompanying kinetics. When analyzing jump GRFs, strength and conditioning professionals must be aware of how much the upper limbs contribute to these forces. Additionally, proper arm swing mechanics must be emphasized when instructing correct jump technique.
Peak Torque and Electromyographic Amplitude Responses to Short-Term Barbell Training in Women
J. Mota, M. Stock, K. Olinghouse, A. Drusch, J. Hernandez, C. Akalonu, and B. Thompson
Texas Tech University
Barbell-based exercises such as the back squat and deadlift have been hallmarks of strength and conditioning and athletic programs for over 4 decades. Purpose: The primary purpose of this investigation was to examine the time course for changes in muscular strength and surface electromyographic (EMG) amplitude during short-term participation in a training program involving barbell back squats and deadlifts. A secondary purpose was to compare these responses between low versus high volume training groups. As many of the previous investigations in this area have studied men, we elected to do so in women. Methods: Forty-three women (mean ± SD age = 21 ± 3 years; body mass = 64.2 ± 12.4 kg) with no previous lower-body strength training experience were randomly assigned to either a control (n = 15), a low volume training (n = 14), or a high volume training (n = 14) group. The training groups performed the barbell back squat and deadlift twice per week for 4 weeks. The low volume training group performed 5 repetitions of 2 sets per exercise; the high volume group performed an additional 2 sets per exercise. Each subject who participated in training was thoroughly taught how to properly perform both exercises by the authors prior to their first training session. All training sessions were closely supervised. The external loads increased by 2.2–4.5 kg each training session for each exercise. Following a thorough familiarization session, each subject visited the laboratory for maximal strength testing on 5 separate occasions during the 4 week study. During each data collection trial, the subjects performed 2, 5-second isometric maximal voluntary contractions (MVCs) of the right leg extensors separated by 2 minutes of rest. Bipolar surface EMG signals were detected from the vastus lateralis during the MVCs. Dependent variables included isometric peak torque (N·m) and the root-mean-square value of the EMG signal, which was expressed as a percentage of the pretest data. Two separate mixed factorial analyses of variance were used to examine the data. Results: For peak torque, there was no group × time interaction and no main effect for group, but there was a main effect for time. The Bonferroni marginal mean pairwise comparisons demonstrated that the peak torque values during the week 4 posttest were greater than those for the pretest, week 1, and week 2 (p ≤ 0.05). Interestingly, when week-to-week effect size statistics were compared between the 2 training groups, the low volume group showed better improvements in leg extension peak torque than the high volume (week 4 Cohen's d = 0.63 and 0.40, respectively). For vastus lateralis EMG amplitude, there was no interaction and no main effects, and similar effect sizes were shown among the 3 groups. Conclusions: Although there was no group × time interaction, barbell back squat and deadlift training resulted in moderate effect sizes for the increase in peak torque. The fact that larger effect sizes were shown for low volume training may be reflective of less training-induced muscle damage or evidence of a minimal work threshold needed for adaptation in this population. Surface EMG amplitude may not be sensitive enough to detect small neuromuscular adaptations associated with 4 weeks of training. Practical Applications: Barbell back squat and deadlift training is an effective means of eliciting rapid and meaningful improvements in isometric strength.
The Reliability of a D-Max Method for Estimating Electromyography Fatigue Threshold During Cycle Ergometry
J. Riffe, D. Fukuda, E. Robinson, A. Miramonti, M. La Monica, J. Hoffman, and J. Stout
University of Central Florida
Purpose: Electromyography fatigue threshold (EMGFT) is defined as the highest level of intensity that an exercise can be sustained without evidence of neuromuscular fatigue as detected by an increase in EMG amplitude. The increase in EMG amplitude observed during a fatiguing task is associated with an increase in muscle fiber recruitment or the increased rate of activation from motor units. The purpose of this investigation was to examine the reliability of a mathematical method (D-max) for estimating EMGFT from a graded exercise test to volitional fatigue. Methods: Eleven men (mean ± SD age = 21.9 ± 1.37 years; 82.1 ± 13.92 kg) completed an incremental exercise test (GXT) on a cycle ergometer to exhaustion on 2 occasions separated by at least 24 hours. The GXT warmup started at 75 W and increased 25 W every 2 minutes until revolutions per minute (RPM) could not be kept at 70–75 RPM. EMG activity was recorded from bipolar surface electrodes placed on the longitudinal axis of the vastus lateralis of the right thigh during the GXT. The root mean square (μVrms) of EMG amplitude was calculated for each 10-second epoch during the GXT. After excluding the warmup, RMS values were averaged and plotted against the midpoint of each 30-second window. These data points were used to generate a third order polynomial regression representing the increase in amplitude over time. Onset of fatigue (TF) was the x-value of the point on the polynomial regression that measured the maximal perpendicular distance from a line formed between the first and last data points. The power output at EMGFT (W) was estimated using TF and the power increments of the GXT. A paired samples t-test was used to compare the EMGFT values between the 2 testing sessions. Test-retest reliability evaluated by calculation of intraclass correlation coefficient (ICC; model 2,1), standard error of the measurement (SEM), and minimal difference to be real (MD) values. Results: Paired samples t-test revealed no significant difference (p = 0.91) in predicted EMGFT for the first (181.57 ± 29.2 W) and second (181.88 ± 26.34 W) trials. An ICC of 0.952 was calculated with an SEM of 6.35 W and MD of 17.61 W. Conclusions: The data from this study suggests that the D-max method provides a reliable means of estimating the power output at EMGFT during a cycle-ergometer GXT to volitional fatigue. Practical Applications: The use of the D-max procedure provides a reliable method for estimating EMGFT in the college-aged population. Further, the ICC, SEM and MD values suggest that utilizing the D-max method to determine EMGFT may be a reliable and sensitive tool for evaluating the effects of training and/or nutritional interventions.
Differences in Collegiate and Recreationally Trained Male Soccer Players on Balance and Stability Measures
N. Sauls, M. Bocanegra, D. Nario, and N. Dabbs
California State University, San Bernardino
Balance is an important skill needed for the execution of movements in sports. For soccer players, balance assists in the development of optimal performance allowing the athlete to successfully execute quick directional changes. There is a direct relationship between the ability of a soccer player to regain equilibrium while changing directions and balance proficiency. Purpose: The purpose of this investigation was to determine the differences in collegiate and recreationally trained male soccer players on balance measures. Methods: Thirteen Division III collegiate trained (age 23.22 ± 3.42 years, height 177.81 ± 6.40 cm, weight 75.21 ± 5.87 kg) and 9 recreationally trained male soccer players (age 20.54 ± 1.76 years, height 174.33 ± 5.44 cm, weight 72.14 ± 11.80 kg) volunteered to participate in one familiarization and one testing session. During the familiarization session, the participants performed a dynamic warm-up, followed by 3 balance tests on the Biodex Balance System. The balance tests consisted of Static Balance (SB), Limits of Stability (LOS), and Single Leg Balance (SLB). Participants returned to the laboratory at least 24 hours following familiarization session and balance was assessed with the same 3 balance tests. The SB and the SLB test consisted of 3 trials at 20 seconds each with a 10 seconds rest between each trial. The LOS test consisted of 3 trials until completion of task, with a 10 s rest between each trial. All of the 3 trials were averaged for each outcome measure. The SB, SLB, and LOS test measured degrees from horizontal and the LOS test also measured time to completion. The level of each test was determined using a 1–12 scale and a static condition. Level one is the most difficult, and allows for the maximum degrees of variation from horizontal in platform movement and 12 is the easiest and allows for the least degrees of variation from horizontal on the platform. In the static level, there is no platform movement. Instead, the static outcome variables measure anterior, posterior, right, and left sway from a center point. During the study, SB was set to static, LOS to level 6, and SLB to level 4. One-way analysis of variance (ANOVA) was conducted to analyze differences between the recreational and collegiate soccer players in all SB, LOS, and SLB variables. Results: There were no significant (p > 0.05) differences between groups in the LOS, SB, and SLB variables. Conclusions: These results show there is no difference between division three collegiate soccer players and recreationally trained soccer players in balance control in static and dynamic conditions. Practical Applications: The lack of difference between the collegiate and recreationally trained soccer players in balance measures may be due to the type of training done at a Division III level. Strength and conditioning coaches should consider incorporating more balance training to ensure a higher level of collegiate performance.
Effects of Height and Mass on Single Leg Balance in Stance vs. PUSH Legs in Skateboarders
M. Wong, D. Patton, and L. Brown
California State University, Fullerton
Skateboarders often skate for long distances and times, several times a week. This may create balance differences between their stance and push legs due to repetitive single leg specificity. Purpose: To compare single leg balance between stance and push legs of transportation skateboarders and evaluate the effects of height and mass. Methods: Eight skateboarders (age = 21.63 ± 1.06 years; HT = 177.89 ± 6.49 cm; mass = 75.49 ± 5.94 kg; regular foot = 3; goofy foot = 5) were tested for single leg balance on a Biodex Balance System. Three trials each were conducted on the stance and push legs. They were instructed to balance on one leg for 20 seconds on an unstable surface (stability level = 2). Results: A paired t-test determined that stance stability (3.79 ± 2.91) and push stability (3.51 ± 2.20) were not different. There was a high correlation (r = 0.92) between stance and push legs. The correlations between height and stance stability (r = −0.19) and push stability (r = 0.03) were not significant. Also, the correlations between mass and stance stability (r = 0.34) and push stability (r = 0.43) were not significant. Conclusions: Since push stability and stance stability showed no differences, skateboarders' long duration of time in double leg balance may have led to similar balance between legs. Neither height nor weight were correlated with stability where we would have expected a negative correlation with height and a positive correlation with weight. Similarly, skateboarders' long duration may have led them to overcome these limitations. Practical Applications: This study investigated only transportation skateboarders, trick skateboarders rely heavily on gravity instead of pushing. Therefore, balance differences should be investigated in trick skateboarders.
Body Composition Characteristics of National Championship NCAA Division 1 Football Players
J. Casey, K. Casey, P. Bishop, and M. Esco
The University of Alabama
American football is a diverse sport composed of athletes with a variety of physiological characteristics. Body size and composition have been shown to be 2 primary components of physical fitness that influence performance of football players. However, limited research is available examining body composition characteristics of elite level collegiate football players. Purpose: The purpose of this study was to describe the body size and composition of national championship-level NCAA Division 1 football players. Methods: One-hundred thirty-five (n = 135) male NCAA Division 1 football players (age = 20.5 ± 1.1 years) participated in this study over a 3-year period (data collected: July of 2008, 2009 and 2010). This team won the National Championship in 2009, while competing in a BCS bowl in 2008. At each visit, body weight (BW) was measured with a calibrated digital scale and body fat percentage (BF%), fat mass (FM), and fat-free mass (FFM) were measured with air displacement plethysmography (BODPOD). Results: Overall body size and composition for the team and by position are compared in Table 1. Conclusions: This study revealed descriptive body composition characteristics of a NCAA D-1 elite-level football team. The body composition values were significantly different among positions. Practical Applications: This study provides body composition reference values that may be beneficial when planning and modifying training and nutrition programs that are specifically designed for enhancing football performance.
Body Composition Changes in Female NCAA Gymnasts Across a Preparatory and Competitive Season
K. Casey, J. Casey, P. Bishop, and M. Esco
The University of Alabama
Body composition is an important component of physical fitness that has been shown to influence athletic performance and health. Limited research is available to examine how body composition changes during preparatory and competitive seasons in athletes, especially female NCAA gymnasts. Purpose: The purpose of this study was to assess longitudinal body composition and anthropometric changes in female NCAA gymnasts throughout a competitive season. Methods: Thirteen female NCAA gymnasts (baseline age = 19.2 ± 1.0 years) participated in this study and visited the laboratory between the second and third week of August (A), October (O), January (J), and March (M) of the 2008–2009 competitive season. At each visit, body weight (BW) was measured with a calibrated digital scale and body fat percentage (BF%), fat mass (FM), and fat-free mass (FFM) were measured with air displacement plethysmography (BODPOD). Changes in each body composition variable were analyzed with repeated measures analysis of variance with paired T-tests as follow-up. Results: Body size and composition values can be found in Table 1. BW significantly increased from A to O (p = 0.0.045) but subsequently remained constant. FFM significantly increased from A to O (p < 0.001) but did not significantly change thereafter. There were no other differences found. Conclusions: This investigation indicated that BW increases, primarily due to an increase in FFM during the preparatory season in female gymnasts. FM remained unchanged throughout both phases. Practical Applications: Monitoring longitudinal changes in body composition can be useful for athletes and strength and conditioning specialists. During the preparatory and competitive phases, gymnasts can be expected to maintain their FM while increasing BW and FFM.
Metabolic, Cardiovascular, and Perceptual Responses During Severe Intensity Treadmill Running: Limiting Factors of Exercise Performance?
J. Switalla,1 H. Bergstrom,1 T. Housh,2 K. Cochrane,2 N. Jenkins,2 S. Buckner,3 J. Goldsmith,4 R. Schmidt,2 G. Johnson,2 and J. Cramer2
1University of Kentucky; 2University of Nebraska-Lincoln; 3University of Mississippi; and 4Florida Atlantic University
Theoretically, critical velocity (CV) demarcates the heavy from severe exercise intensity domains, and it has been suggested that any velocity performed above CV drives metabolic, cardiovascular, and perceptual responses to peak values. Purpose: This study examined the oxygen consumption (V[Combining Dot Above]O2), respiratory exchange ratio (RER), heart rate (HR), and ratings of perceived exertion (RPE) responses during 4, constant velocity runs performed above CV to determine if exhaustion necessitates the attainment of peak values. Methods: Thirteen runners (mean ± SD; age = 23 ± 3 years; body mass = 71 ± 12 kg) performed an incremental treadmill test to exhaustion for the determination of the V[Combining Dot Above]O2 (V[Combining Dot Above]O2peak), RER (RERpeak), HR (HRpeak), and RPE (RPEpeak) peak as well as the velocity associated with V[Combining Dot Above]O2peak (v V[Combining Dot Above]O2peak). On separate days, V[Combining Dot Above]O2, RER, HR, RPE, and time to exhaustion (Tlim) were measured during 4, constant velocity runs (V1, V2, V3, V4; V1 = highest, V4 = lowest). Critical velocity was defined as the slope of the linear relationship between the total distance and Tlim from the 4 constant velocity runs. Mean differences among V[Combining Dot Above]O2, RER, HR, and RPE values from the incremental test and constant velocity runs were examined using separate one-way repeated measures ANOVAs (p ≤ 0.05) and pairwise comparisons with Bonferroni corrected dependent samples t-tests (p ≤ 0.005). Results: The mean Tlim values for V1 (15.2 ± 1.6 km·h−1; 97 ± 4% vVO2peak), V2 (14.7 ± 1.7 km·h−1; 93 ± 4% vVO2peak), V3 (14.2 ± 1.6 km·h−1; 90 ± 4% vVO2peak), and V4 (13.7 ± 1.6 km·h−1; 86 ± 4% vVO2peak) were 7.15 ± 1.21, 9.25 ± 1.71, 12.81 ± 1.91, and 17.33 ± 2.74 minutes, respectively. Critical velocity (12.6 ± 1.6 km·h−1) occurred at 80 ± 5% of vVO2peak. The V[Combining Dot Above]O2 values at exhaustion for V1 (3.41 ± 0.96 L·min−1) and V2 (3.33 ± 0.91 L·min−1) were not different from V[Combining Dot Above]O2peak (3.48 ± 0.96 L·min−1). The V[Combining Dot Above]O2 values at exhaustion for V3 (3.28 ± 0.89 L·min−1) and V4 (3.16 ± 0.82 L·min−1), however, were less than V[Combining Dot Above]O2peak. The RER (1.04–1.11) and HR (186–187 b·min−1) values at exhaustion for each of the constant velocity runs (V1–V4) were less than RERpeak (RER = 1.15 ± 0.04) and HRpeak (193 ± 9 b·min−1), respectively. There were, however, no differences in the RPE values at exhaustion (19.7–20) and RPEpeak (19.7 ± 0.5) for any of the runs (V1–V4). Conclusions: These finding indicated that for intensities greater than CV and within the severe domain, volitional exhaustion can occur within ∼20 minutes without the attainment of V[Combining Dot Above]O2, RER, or HR peak. The RPE was the only variable that consistently reached peak values. Thus, the perception of effort and volitional exhaustion were not necessarily limited by O2 delivery/uptake and cardiovascular function, but may have been related to increased muscle temperature and/or neuromuscular fatigue. Practical Applications: The CV is an individually derived fatigue threshold that has a number of applications in exercise testing and performance evaluation. For exercise intensities above the CV, however, V[Combining Dot Above]O2 and HR should not be the only criteria used to examine performance. The perceptual responses consistently reached peak values and may provide a way to monitor other factors that can potentially limit exercise performance within the severe intensity domain, such as temperature or metabolic changes within the working leg, thigh, or respiratory muscles.
Teleoanticipation and Effects of Sex Differences on Pacing Strategy
N. Hanson,1 J. Buckworth,2 M. Miller,1 and T. Michael3
1Western Michigan University; 2University of Georgia; and 3WMU
Previous studies have shown some sex-related differences in pacing during running. Women, in general, often seem to adopt a more conservative pacing strategy compared to men. Teleoanticipation is the notion that pacing is determined by working backward from an endpoint; manipulation or removal of the endpoint can provide further insight into how pacing strategies are implemented. Purpose: The primary goal of this study was to determine if sex-related differences in pacing strategy are present, and how pacing is affected by knowledge of an endpoint. It was hypothesized that the women would have fewer changes in speed, choosing a particular pace and not deviating from it. Methods: Seventeen recreational runners (7 men, 10 women) participated in this study. Subjects completed a V[Combining Dot Above]O2max test and participated in 2 conditions: (a) a run with an unknown endpoint that was relative to each subject, calculated based on the subject's running history; and (b) a run to the same distance with knowledge of the endpoint. In both conditions the subjects were able to self-pace but received no feedback and were blind to speed, distance and elapsed time. Their overall finish time was recorded for each condition, and the number of speed changes (increases and decreases) was collected. Independent sample t-tests were used to determine the differences in finish time, speed increases and speed decreases between men and women. Paired samples t-tests were used to determine the difference in total time between conditions. Results: V[Combining Dot Above]O2max was higher for men (men: 57.6 ± 8.3; women: 49.1 ± 1.9; p = 0.028) and women reported lower weekly mileage. The women ran a significantly shorter calculated distance (men: 5.00 ± 1.40 miles, women: 3.51 ± 0.64 miles, p = 0.009), but no sex-related differences were present in absolute finishing time within either endpoint condition (unknown: p = 0.122; known: p = 0.086). No differences were seen between men and women in regards to the number of speed increases or decreases in either endpoint condition (all p > 0.05). For all subjects, there were no differences between endpoint condition for speed increases or decreases (all p > 0.05) but both men and women finished faster when the endpoint was known (31:04 ± 8.39 minutes vs. 32:39 ± 8:26 minutes; p = 0.001). Conclusions: There was no effect associated with sex or endpoint condition on the absolute number of speed increases or decreases. However, the lack of a difference in absolute finish time despite the significant difference in distance run shows that the women did run at a slower overall pace compared to the men. Practical Applications: Coaches of runners should be aware that when using an unknown endpoint during treadmill training or when athletes are allowed to self-pace, they will likely run at a more conservative pace. If a coach does not specify a time or distance component during training a session, this may adversely affect conditioning by impacting the intensity of the training session. Additionally, coaches need to be aware that women runners may adopt a more conservative pace compared to men when training sessions have unknown time or distance.
Effects of Inspiratory Muscle Training on Pulmonary Function, Oxygen Uptake Kinetics, and Exercise Tolerance in Athletes
C. Cheng,1 Y. Kuo,2 W. Hsu,3 P. Lin,4 C. Pan,4 and Y. Lai2
1Department of Athletic Performance, National Taiwan Normal University; 2Department of Physical Education, National Taiwan Normal University; 3Graduate Institute of Sports Training, University of Taipei; and 4Department of Athletic Performance, National Taiwan Normal University
The respiratory muscle (RM) metaboreflex activated by the RM fatigue might induce vasoconstriction and reduce blood flow in working muscles, thus increasing contractile failure of locomotor muscles. The specific inspiratory muscle training (IMT) might attenuate or delay the RM fatigue by improved pulmonary functions. However, the ergogenic effect of IMT on exercise performance for well-trained athletes remains controversial. Purpose: This study examines the effects of IMT on pulmonary function, oxygen uptake (V[Combining Dot Above]O2) kinetics, and high-intensity exercise tolerance in athletes. Methods: Thirty-six male athletes (age 18 ± 2 years; height 1.78 ± 0.09 m; weight 69 ± 11 kg; V[Combining Dot Above]O2max 52 ± 7 ml·kg−1·min−1) were randomly assigned to an IMT (n = 12), sham treatment (SHAM, n = 12), or control (CON, n = 12) group. The IMT group performed IMT (30 breaths twice daily at 80% of maximal inspiratory mouth pressure [PImax]) for 4 weeks, and the SHAM group performed the 4-week of sham treatment (30 breaths twice daily at 15%PImax), and the CON group did not perform any RM training. Before and after the intervention period, all participants performed a battery of pulmonary function tests, the incremental exercise test, and square-wave tests. The pulmonary function tests consisted of the measurements of forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), PImax, and maximal voluntary ventilation (MVV). The square-wave tests were performed at moderate (80% of gas exchange threshold [GET]), severe (GET plus 60% of differences in power outputs between GET and maximal V[Combining Dot Above]O2 [V[Combining Dot Above]O2max]), and maximal (100%V[Combining Dot Above]O2max) intensities on a cycling ergometer for assessing the V[Combining Dot Above]O2 kinetics and exercise tolerance. The blood lactate (La) concentrations and pH values were evaluated before and after the exercise tests. Results: The PImax (from 135 ± 23 to 165 ± 24 cmH2O, p ≤ 0.05) and MVV (from 171 ± 41 to 190 ± 39 L·min−1, p ≤ 0.05) were significantly improved after IMT, however, no significant changes were found in the SHAM and CON groups. There were no significant differences on the FVC and FEV1 before and after 4-week intervention in the 3 groups. Although the maximal minute ventilation (VE) was significantly increased after IMT (from 134 ± 23 to 141 ± 27 L·min−1, p ≤ 0.05), no significant differences on V[Combining Dot Above]O2max, La, and pH values were found between before and after intervention in each group. During moderate exercise, no significant changes were found on VE, phase II time constant, and fundamental amplitude after interventions. No significant group × time interactions were observed for the time to exhaustion, VE and V[Combining Dot Above]O2 at exhaustion, La and pH values at post-exercise, fundamental and slow component amplitudes during either severe or maximal exercise. Conclusions: The 4-week IMT might improve the lung function in well-trained athletes, however, it could not speed the V[Combining Dot Above]O2 kinetics and enhance the high-intensity exercise tolerance. Practical Applications: Since the breathing might be a limiting factor for exercise performance, strength and conditioning professionals are encouraged to use the IMT strategy for improving pulmonary function in well-trained athletes. However, further studies are needed to explore the effects of long-term (>4-week) IMT program on the exercise tolerance, which is a determinant of endurance performance, in athletes.
Effects of Two Weeks of High-Intensity Interval Training on Triathlon-Specific Performance and Physiological Responses in Adolescent Triathletes
M. Hsu1, C. Lee2, and T. Liu3
1Department of Sports Medicine, Kaohsiung Medical University; 2Physical Education Section of General Education, National Sun Yat-sen University; and 3Chinese Taipei Triathlon Association
Low-volume high-intensity interval training (HIT) has been recently attracted extensive attention worldwide since many studies reported the short-term HIT may induce significant improvements in metabolic function and performance in athletes. However, it is unclear whether these findings can be successfully applied to triathlon that requests athletes to perform different exercise modes in the 3 disciplines of swimming, cycling and running. Purpose: This study examined the effects of 2 weeks of HIT on the anaerobic and aerobic capacities, sprint distance test and physiological responses. Methods: Twelve adolescent triathletes were recruited, and performed a 6 × 10 seconds sprint test and a peak oxygen uptake (V[Combining Dot Above]O2peak) test on a cycle ergometer in the laboratory. The sprint distance test, consisted of 0.75 km of swimming, 20 km of cycling, and 5 km of running, was conducted using their own instruments to mimic competitive situation. The 6-day training blocks are separated by 1 day of recovery. In each HIT session, participants perform interval sprints at an intensity corresponding to 90–100% of peak heart rate under 3 conditions: cycling with 4 sets of 2 minutes and 2 sets of 4 minutes exercise bouts, running with 2 sets of 5 repetitions of 50 seconds and 1 set of 10 repetitions of 30 seconds sprint, swimming with 8 repetitions of 100 m and 8 repetitions of 50 m. The work-to-rest ratio was set from 1:1 to 1:2 for all HIT sessions. Results: V[Combining Dot Above]O2peak was increased by 2.2% and maximal aerobic power was increased by 5.7% from pre-to post-training (p ≤ 0.05). For the anaerobic capacities, the mean power output and total work were significantly increased at Sprints 3 and 4 during the 6 × 10 seconds sprint test after HIT training (p ≤ 0.05); however, the peak power output was not significantly different between pre- and post-training (p > 0.05). Blood lactate was significantly decreased by 2.9% at Sprint 5, but no differences were observed at other sprints between pre- and post-training. At pre-training, the blood glucose leveled off during the first 3 sprints, but significantly increased after sprint 5 until 5 minutes after 6 × 10 seconds sprint test; however, the blood glucose concentrations at post-training were at steady state from pre-to post-test. Two weeks of HIT induced significant improvements in time to completion for the 0.75 km of swimming (increase by 3.9%) and 20 km of cycling (increase by 8.1%) tests, furthermore, the rating of perceived exertion (RPE) was significantly higher than that at pre-training. However, the performance and RPE during the 5 km of running test were not significantly changed after HIT intervention. No significant differences were showed on cortisol, testosterone, human growth hormone, and hemoglobin between pre- and post-training. Conclusions: The data indicated that 2 weeks of triathlon-specific HIT regimen could be beneficial for increasing anaerobic and aerobic capacities, and performance in adolescent triathletes. Practical Applications: The HIT has been used as a training strategy to enhance aerobic capacity for untrained and trained adults. This study provides support for including the short-term HIT in the training program of adolescent triathletes to improve the cardiorespiratory capacities and performance. It can be suggested to coaches and triathletes that the low volume HIT can be appropriately added to training program during the in-season period.
Impact of Precooling the Upper Body on Time Trial Paced Cycling in the Heat
G. Ryan,1 C. Katica,2 R. Herron,3 S. Bishop,4 and J. Wingo5
1University of Montana Western; 2Pacific Lutheran University; 3Auburn University at Montgomery; 4Montevallo University; and 5University of Alabama
Purpose: The purpose of this study was to test the hypothesis that cooling the upper body during a warm-up enhances performance during a subsequent 16.1-km simulated cycling time trial in a hot environment. Methods: Eight, trained male cyclists (average V[Combining Dot Above]O2peak = 57.8 ± 5.0 ml·kg−1·min−1) completed 2 simulated 16.1-km time trials in a warm environment (30.0 ± 0.5° C, 43.8 ± 2.0% relative humidity) each separated by 72 hours, in a counterbalanced, repeated measure design. On each occasion participants warmed up for 20 minutes while either wearing head and neck ice wraps, along with torso cooling using an ice vest (COOLING), or no cooling apparatus (CONTROL). Results: Following the warm-up mean skin temperature (Tsk), mean body temperature (Tb) and rating of thermal comfort (RTC) were significantly lower (all p ≤ 0.05). However, rectal temperature (Tre) was unaffected (p = 0.35). The effects of precooling on Tsk and Tb were not sustained during exercise such that values for COOLING and CONTROL were not different. Likewise, time to completion was not significantly different between trials (30.4 ± 3.5 minutes vs. 29.3 ± 3.6 for CONTROL and COOLING, respectively, p = 0.09). Despite a lack of statistical significance, the time trial was completed faster during COOLING compared to CONTROL by 6 out of 8 (75%) participants with an average time that was 1.06 ± 0.1 minutes faster. Conclusions: These data suggest that competitive cyclists may experience a modest benefit, if any, while utilizing cooling modalities during an active warm-up before a time trial. Practical Applications: Future research should be considered, but due to the approaching significance in time trial performance given the small sample size, the introduction of upper body cooling prior to cycling competition may lead to improved performance in trained cyclists.
The Impact of Suggestion and Music on Endurance Running Performance
J. Schoffstall, J. Steele, E. Picking, A. Espinoza, and K. Lemire
Purpose: The purpose of this study was to examine the impact of suggestion on endurance running performance. Methods: Thirty active, low-risk stratified, college-age students were recruited as subjects. All subjects performed two 15 minute running trials in random order on a 200 m indoor track. One trial was completed while listening to no music. The other trial was completed while listening to fast paced music. Ten of the subjects were told that the music would improve their performance. Ten of the subjects were told that the music would hinder their performance. Ten of the subjects were told that the music would have no impact on their performance. All of the subjects listened to the same track of music. Results: There was a significant difference between the overall no music trial (14.0 ± 3.2 laps) and the music trials (14.5 ± 3.3 laps) Conclusions: Based on the results of this study, it appears that the power of positive suggestion does have a benefit on running performance. Practical Applications: Coaches and trainers not only develop and prescribe training programs for athletes, but the coaches and trainers are also prime sources of motivation. Motivation is often given in the form of verbal encouragement, which when positive in natural can spur the athlete toward better performance.
Validity of a Smart Phone Application and Finger Sensor for Evaluating Supine and Standing HRV in Athletes
M. Esco, and A. Flatt
The University of Alabama
Purpose: The purpose of this investigation was to cross-validate a smart phone heart rate variability (HRV) application and finger sensor (HRV-APP) with an electrocardiogram (ECG) for determining log-transformed root mean square of successive R-R intervals multiplied by 20 (lnRMSSDx20) in collegiate athletes. Methods: Six male (height = 184.33 ± 6.47 cm, weight = 79.16 ± 8.96 kg, %BF = 16.22 ± 4.66) and 7 female soccer players (height = 164.57 ± 6.69 cm, weight = 61.29 ± 6.80 kg, %BF = 29.29 ± 5.64) volunteered for this study. The participants HRV was simultaneously determined in supine and standing positions via the HRV-APP and criterion ECG recordings. The lnRMSSDx20 parameters for each position were automatically determined by the HRV-APP and manually for the ECG recordings by the investigator. The supine and standing lnRMSSDx20 values were compared with Paired T-tests, correlation coefficients, standard error of the estimate (SEE) and the method of Bland-Altman. Results: The ECG-derived lnRMSSDx20 was 87.34 ± 8.16 for supine and 69.63 ± 9.81 for standing. The HRV-APP lnRMSSDx20 was 87.21 ± 6.94 for supine and 71.18 ± 9.21 for standing. The laboratory and HRV-APP supine measures were not significantly different (p > 0.05). However, the HRV-APP provided significantly higher standing lnRMSSDx20 values compared to the laboratory-derived measures (p ≤ 0.05), but the effect size was trivial (Cohen's d = 0.16). There were strong significant correlations when comparing the supine (r = 0.96, p < 0.01) and standing (r = 0.99, p < 0.01) lnRMSSDx20 measures. In addition, the HRV-APP revealed a SEE of 2.34 and 1.16 for supine and standing measures, respectively. The limits of agreement ranged from 4.61 below to 4.87 above the constant error of −0.13 for the supine measures and from 3.98 above to 0.88 below the mean error of 1.55 for the standing measures. Conclusions: The HRV-APP appeared to provide accurate measures of lnRMSSDx20 in the supine and standing position when compared to ECG measures obtained in the laboratory within the current sample of athletic participants. The supine and standing lnRMSSDx20 HRV-APP values were non-significant and trivial, respectively, compared to the laboratory measures. In addition, the HRV-APP provided very strong correlation coefficients, small SEE, and tight limits of agreement compared to the criterion ECG for lnRMSSDx20 in both positions. Practical Applications: HRV is becoming a promising method for monitoring physiological adaptation and recovery status in athletes in response to training. Technological advances have made available convenient methods for determining HRV in practical settings. The current findings suggest that the HRV-APP provides acceptable lnRMSSDx20 values in supine and standing position compared to laboratory-derived measures in collegiate athletes. These results could lead to increased utility of the HRV-APP for evaluating ultra-short-term HRV in athletes by sports practitioners and scientists.
Novice Cyclists Show Improved Aerobic Fitness Measures Following Ride Across the United States
L. Judge,1 D. Bellar,2 B. Norris,3 W. Weatherholt,3 R. McMullen,3 S. Arnett,3 M. Schafer,3 and D. Hoover3
1Ball State University; 2University of Louisiana at Lafayette; and 3Western Kentucky University
Purpose: The physiological responses and adaptations experienced by novices engaging in cross-country cycling have received little attention in the scientific literature. Such a bicycle ride typically involves a sizeable increase in physical activity for most individuals, but the acute and chronic effects of such an endurance feat are not well understood. Greater understanding of this issue is needed, as strength and conditioning professionals increasingly play a supervisory role in training individuals who engage in endurance cycling. This study assessed the changes in aerobic capacity (AC) and time to volitional failure (TVF) during maximal cycling tests conducted on a group of novice cyclists prior to and following a cross-country ride, as well as in a group of controls. Methods: Five novice cyclists (21.0.2 ± 0.71 years, 187.842 ± 6.50 cm, 82.84 ± 5.42 kg) completed laboratory testing prior to and after the cross-country ride, as did controls (20.2 ± 1.79 years, 178.31 ± 4.17 cm, 78.34 ± 7.55 kg). The novice cyclists visited the laboratory on 2 occasions, completing a maximal cycle test prior to and upon completion of a cross-country bicycle ride. The controls remained in the university community and engaged in their typical freely-chosen activities. Testing occurred 60 days apart for both groups. Following a standardized warm up, subjects rode an electronically-braked cycle ergometer until volitional failure. Conditions were controlled and measured by computer, and inspired and expired gases were collected via open-spirometry. The following variables were assessed continuously (30 s average) during each trial: V[Combining Dot Above]O2, V[Combining Dot Above]CO2, VE, METs, RER, VT, FEO2, FECO2, and HR. Two-way repeated measures ANOVA were used for statistical analysis. Results: For AC (V[Combining Dot Above]O2 max), significant differences were found pre-post within both groups (F(1,8) = 5.418, p = 0.048), with the cyclists improving and the controls decreasing in AC. Significant differences in AC were also found between the groups (F(1,8) = 43.815, p = 0.00). For TVF, significant differences were also found pre-post within both groups (F(1,8) = 33.108, p = 0.000), with the cyclists improving and the controls backsliding in TVF. Significant differences in TVF were also found between the groups (F(1,8) = 46.401, p = 0.00). Conclusions: These results have scientific and practical relevance given the few studies on the effects of cross-country cycling upon aerobic fitness in novice cyclists. These findings suggest that novice cyclists significantly increase their aerobic capacities and time to volitional failure as an adaptation to an extended ride across the United States. Practical Applications: These findings are consistent with the many reports indicating that aerobic performance measures improve with habitual training. Strength and conditioning professionals are encouraged to monitor aerobic fitness and emphasize aerobic training in all individuals involved with endurance cycling.
Ratings of Perceived Exertion Lessened Following Bike Ride Across America
S. Arnett,1 B. Norris,1 W. Weatherholt,1 R. McMullen,1 L. Judge,2 M. Schafer,1 and D. Hoover1
1Western Kentucky University; and 2Ball State University
Purpose: Cross-country bike rides have increased in popularity in the past decade. The scientific literature contains few known studies regarding the physiological responses and adaptations experienced by novice cyclists who engage in such pursuits. Deeper understanding of this topic is needed, as strength and conditioning professionals increasingly play a supervisory role in training individuals who engage in endurance cycling. This study explored the effects of a cross-country bike ride upon OMNI ratings of perceived exertion (RPE) during a graded cycling test. Methods: Five novice cyclists (21.0.2 ± 0.71 years, 187.842 ± 6.50 cm, 82.84 ± 5.42 kg) completed laboratory testing prior to and after the cross-country ride, as did controls (20.2 ± 1.79 years, 178.31 ± 4.17 cm, 78.34 ± 7.55 kg). The novice cyclists visited the laboratory on 2 occasions, completing a maximal cycle test prior to and upon completion of a cross-country bicycle ride. The controls remained in the university community and engaged in their typical freely-chosen activities. Testing occurred 60 days apart for both groups. Following a uniform warm up, subjects rode an electronically-braked cycle ergometer until volitional failure. Conditions were controlled and measured by computer. Measures of OMNI RPE, inspired and expired gases, and gross motor coordination were collected during each trial. Two-way repeated measures ANOVA were used for statistical analysis. Results: Significant differences were found between pre- and post-conditions (F(1,4) = 986.13, p = 0.00) for OMNI RPE scores during a maximal cycle test. Significant differences were also evident for interactions between condition (pre vs. post) × group (cyclists vs. controls) (F(1,4) = 43.20, p = 0.003). Significant differences in V[Combining Dot Above]O2 max were found between the groups (F(1,8) = 43.815, p = 0.00), as were significant differences in time to volitional failure pre-post within both groups (F(1,8) = 33.108, p = 0.000). Conclusions: Given the few studies on the effects of cross-country cycling in novice cyclists, these findings have both scientific and clinical relevance. These findings suggest that novice cyclists significantly reduced their OMNI RPE values as an adaptation to an extended ride across the United States. More study is needed on the impact of endurance cycling on RPE during prolonged activities, given the role of perception in gauging exercise intensity in many forms of training and rehabilitation. Practical Applications: These findings are consistent with the many reports indicating that ratings of perceived exertion lessen with habitual training. Strength and conditioning professionals are encouraged to monitor aerobic fitness and emphasize aerobic training in all individuals involved with endurance cycling.
An Analysis of the Heart Rate Response to a Thirty Minute Expert Level Wii Sports Resort Canoeing Exercise Session
A. Bosak1 and K. Huet2
1Liberty University; and 2Armstrong State University
It can often be difficult to complete daily physical activity when leading a hectic lifestyle. Hence, finding alternative, yet fun exercise methods that can assist individuals with “sneaking physical activity” into their daily life is quite important and might possibly increase compliance. Ironically, playing video games is considered a fun activity and the use of interactive video games, as a potential mode of exercise, has been assessed utilizing a variety of “exergames”. However, despite how fun playing Nintendo Wii Sports Resort Canoeing (WSRC) can be, this particular exergame has only been evaluated a few times to confirm if it could serve as a form of cardiovascular exercise and more importantly, only the intermediate level was utilized for the intensity setting. Thus, playing WSRC at the expert level, in hopes of it serving as a potential cardiovascular workout, has not been evaluated. Purpose: To determine if playing 30 minutes of WSRC at the expert level yields a Heart Rate Response (HRR) that meets the American College of Sports Medicine (ACSM) guidelines for moderate physical activity intensity as indicated by a HRR intensity of 64–76.9 percent of a subject's maximum heart rate (HRmax). Methods: Thirty-four above averagely fit collegiate males (n = 21) and females (n = 13) participated in a maximal treadmill graded exercise test (GXT) to measure HRmax and maximal oxygen consumption (V[Combining Dot Above]O2max) and then, 3–7 days later, completed a 30 minutes WSRC expert level exergaming session. The mean HRR of the 30 minutes WSRC session was recorded for each individual and reported as a percentage of their HRmax. Starting and ending HR and Rating of Perceived Exertion (RPE) values were assessed using ANOVA statistical methods with significant differences considered at p ≤ 0.05. Results: The mean HRR to a 30 minutes WSRC expert level exergaming session was 67.1 ± 10.2 percent of HRmax with 18 subjects having a mean HRR greater than 64%. Also, ending HR and RPE was significantly greater than starting HR and RPE which indicates that the subjects were more fatigued at the end of the exergaming session then they were at the start of it. Conclusions: The subjects' mean HRR during a WSRC expert level 30 minutes exergaming session met the ACSM moderate physical activity intensity guidelines suggesting that playing 30 minutes of WSRC at the expert level provides a moderate to vigorous aerobic response in above averagely fit subjects. Practical Applications: The current study's results suggest that people of various fitness levels (i.e., sedentary, averagely fit, team sport athletes, etc.) might have a somewhat similar response to playing WSRC if they were to engage in this specific exergaming activity. Thus, WSRC may be a viable exercise option for those who seek alternative, yet amusing ways to meet their daily aerobic activity requirements. Also, it is possible that playing WSRC may serve as another option, yet not a replacement, to upper body ergometry (UBE) for team sport athletes (i.e., soccer, lacrosse, field hockey, etc.) who have a lower body injury and are seeking to either maintain or reduce the severity of decline of their cardiovascular levels until they are able to return to their normal endurance training sessions. Future research should assess if changing the WSRC exergame playing position (i.e., from a seated position to a standing position) might contribute to an even greater cardiovascular training session.
The Relationship Between Soccer Performance Tests and the Ranking Order of Collegiate Soccer Players
S. Broadbent,1 J. Winchester,2 and F. Wyatt3
1APEC; 2School of Physical Therapy, University of Incarnate Word; and 3Department of Athletic Training and Exercise Physiology, Midwestern State University
Specific tests are utilized to measure soccer performance components either pre and post training or pre and post season to determine changes in performance. In addition, such testing is often used as a way to evaluate athletes by coaches. However, the relationship that commonly used tests have with coaches' perception of player ability is in question. Purpose: The purpose of the study is to explore the relationship with perceived player ability and tests of physical performance. Methods: Twenty-four collegiate soccer players, 15 men (mean ± SD; age = 20 ± 1.30, mean ± SD; mass (kg) = 80.63 ± 6.69, mean ± SD; height (cm) = 180.7 ± 7.14) and 9 women (mean ± SD; age = 20 ± 0.3, mean ± SD; mass (kg) = 63.93 ± 8.13, mean ± SD; height (cm) = 166.94 ± 3.84), volunteered for this study. Performance testing included: Yo-Yo Intermittent Recovery Test Level 2, Repeated Sprint Ability test, Vertical Jump, 1 Repetition Maximum Back Squat, 30 Meter Sprint, and the Soccer Specific Agility test, measuring aerobic capacity, speed endurance, power, strength, speed, and agility respectively. All subjects ranked and rated themselves as well as their teammates, and coaches ranked and rated their own teams. Performance attributes were ranked based on the level of perceived influence on soccer performance by both coaches and players. Correlations were established via Pearson's product moment correlation coefficient, and the criterion alpha level was set a priori at p = 0.05. Results: Significant correlations between mean male player rank and male aerobic capacity (r = −0.74 and p = 0.002); mean male player rank and the ranking of the males aerobic capacity scores (r = 0.74 and p = 0.002); mean male player rating and male aerobic capacity (r = 0.76 and p = 0.001); mean male player rating and the ranking of the males aerobic capacity scores (r = −0.78 and p = 0.001); mean male coach rank and male aerobic capacity (r = −0.54 and p = 0.036); mean male coach rank and the ranking of the males aerobic capacity scores (r = 0.60 and p = 0.018); mean male coach rating and the ranking of the males aerobic capacity scores (r = −0.56 and p = 0.029); mean male coach rating and male absolute peak power (r = 0.59 and p = 0.021) and mean male coach rating and the ranking of the males absolute peak power scores (r = −0.61 and p = 0.015) within the men's team. Conclusions: Higher ranked and rated players demonstrated greater aerobic capacity and absolute peak power within the men's soccer team, with aerobic capacity showing the strongest relationship. Interestingly, coaches and players seem to have different perceptions in regards to which attributes are the most influential for soccer performance (coaches from the men's team identified power, but the players selected aerobic endurance). Practical Applications: Coaches can use this type of testing to identify which performance components are most significant for individual ability as well as their significance with the higher ranked players. This information could generate a more specific training plan for a team and individuals. This may lead to improvements in talent identification for players which match a particular coach's style of play as well as more focused training interventions and monitoring of training.
Effects of Caffeine Ingestion on Inspiratory Muscle Function
C. Nicks, S. Bowers, and E. Martin
Columbus State University
Purpose: The influence of caffeine on measures of maximal strength is somewhat equivocal. Previous researchers have primarily reported on the impact of caffeine on upper and lower body measures of muscle strength. As such, little is known about the potential effects caffeine may have on the respiratory muscles. The purpose of the study was to determine the effects of a moderate dose of caffeine on inspiratory muscle function. Methods: Sixteen (9 male, 7 female) healthy adults (age = 24.3 ± 6.2 years; height = 1.76 ± 0.11 m; weight = 80.1 ± 16.8 kg) volunteered to participate in the study which required 3 visits to the laboratory. The study was a double-blind, placebo-controlled, cross-over design. During the initial visit, baseline data was collected and participants were thoroughly familiarized with the process of obtaining maximal inspiratory pressure (MIP) using a hand-held pressure meter. The second and third visits were scheduled at least 48 hours apart. Upon arrival, participants ingested either a 5 mg·kg−1 dose of caffeine (CAF) or placebo capsule (PL). After 1 hour, participants completed at least 12 maximal inspiratory Mueller maneuvers (1 minute between each attempt) to obtain MIP. Maximal inspiratory peak pressure (PIpeak) and maximal rate of pressure development (MRPD) were also recorded during all attempts. Results: The CAF trial resulted in a significantly higher (p ≤ 0.05; d = 0.21) MIP compared to the PL condition (154 ± 34.7 vs. 146.2 ± 36.3 cmH2O). Significant differences (p ≤ 0.05; d = 0.20) were also observed in PIpeak, as CAF was higher (165.2 ± 35.6 cmH2O) than PL (157.8 ± 36.7 cmH2O). No significant differences were observed in MRPD (CAF = 953.4 ± 337.8 vs. PL 917.6 ± 301.9), p > 0.05. Conclusions: A moderate dose of caffeine resulted in small, but significant increases in MIP and PIpeak. Although observed effect sizes were small (0.21 and 0.20), the percentage difference in MIP between the CAF and PL conditions was similar to previous studies where CAF increased measures of muscle strength. The results of this study add to the growing body of literature relating to caffeine and its effects on measures of muscular strength. Practical Applications: MIP is assessed in clinical and athletic populations as a measure of inspiratory muscle strength. Practitioners should be aware of the influence caffeine can have on this measurement if reliable baseline measurements are of concern. The influence of caffeine on inspiratory muscles during exercise may also warrant further examination.
Consumption of a Purported Testosterone-Boosting Supplement Improves Body Composition in Recreationally-Active Men
P. Falcone,1 J. Joy,2 R. Vogel,1 M. Mosman,1 C. Hughes,3 J. Griffin,4 K. Paulin,5 M. Kim,1 and J. Moon1
1MusclePharm; 2Concordia University Chicago/MusclePharm; 3Grand Valley State University; 4Widener University; and 5University of Colorado
Increasing testosterone and lowering estrogen combined with resistance training can lead to improvements in body composition in some men. Testosterone-boosting supplements (TB) may exert these effects; however, it is still unclear whether many TB are effective when consumed chronically. Purpose: To determine the effects of a TB ingested for 8 weeks on body composition. Methods: Eighteen trained men (age: 25.8 ± 4.3 years; height: 176.7 ± 5.0 cm; weight: 80.35 ± 12.0 kg) completed a double-blind, placebo-controlled study. For 8 weeks, the TB group (n = 10) consumed a TB twice daily, and the placebo (PLA) group (n = 8) consumed a visually identical placebo in the same manner. Before and after the supplementation period, lean body mass, fat mass, and percent body fat were measured via dual X-ray absorptiometry, and cross-sectional area of the rectus femoris was measured via ultrasound. During the 8-week supplementation period, subjects in both groups engaged in a supervised, periodized, progressive resistance training regimen. Diet and unsupervised exercise were tightly controlled throughout the supplementation period. Results: According to DXA, the change in FM was significantly lower in TB (0.16 ± 0.93 kg; p = 0.04) compared with PLA (1.52 ± 1.62 kg). The change in %BF was significantly lower in TB (−0.68 ± 1.3%; p = 0.03) compared with PLA (0.88 ± 1.52%). According to ultrasound, the change in CSA was significantly higher in TB (0.75 ± 0.35 cm2; p = 0.02) compared with PLA (0.12 ± 0.50 cm2). No significant changes were measured for body weight or LBM. Conclusions: Eight weeks of supplementation with TB significantly attenuates an increase in FM and lowers %BF as measured by DXA, as well as significantly increases CSA via ultrasound, compared to placebo. Practical Applications: For healthy individuals interested in improving body composition via resistance training, chronic consumption of a TB could augment those changes. Consuming a TB could be beneficial for any young, healthy athlete interested in reducing their percent body fat and in increasing muscular cross-sectional area.
Consuming a Multi-Ingredient Thermogenic Supplement for Twenty-Eight Days Is Apparently Safe in Recreationally Active Adults
R. Vogel,1 J. Joy,2 P. Falcone,1 M. Mosman,1 M. Kim,1 and J. Moon1
1MusclePharm; and 2Concordia University Chicago/MusclePharm
Increased awareness of the health risks associated with overweight and obesity has sparked interest in finding effective weight loss strategies. Thermogenic (TRM) supplements are often viewed as a viable option for those looking to decrease body weight or fat mass. Many TRM supplements are formulated with multiple ingredients purported to increase energy expenditure, suppress appetite, or both. Stimulants such as caffeine anhydrous and green tea extract are often combined to achieve these effects. However, as has been the case in the past, some of the most efficacious ingredients can pose a significant health risk to certain populations, and have subsequently been removed from the market. With this in mind, it is important to verify the safety and potential side effects of TRM supplements with chronic consumption. Purpose: To assess the safety of daily consumption of a multi-ingredient TRM supplement over a period of 28 days in healthy men and women. Methods: 23 recreationally active men and women (11 male, 12 female; 27.1 ± 5.4 years, 171.6 ± 9.6 cm, 76.8 ± 16.1 kg) participated in this simple randomized study. Participants were assigned either to consume 2 servings daily of a multi-ingredient TRM supplement (SUP; n = 9) or remain unsupplemented (CRL; n = 14) for 28 days. All were instructed to maintain their habitual dietary and exercise routines for the duration of the study. Fasting blood samples, as well as resting blood pressure and heart rate, were taken prior to and following the supplementation period. Samples were analyzed for complete blood counts, comprehensive metabolic, and lipid panels. Results: Significant (p ≤ 0.05) group by time interactions were present for diastolic blood pressure, creatinine, eGFR, chloride, CO2, globulin, albumin:globulin ratio, and HDL cholesterol. Each of these variables remained within the accepted physiological range. Data are presented as means ± SD in Table 1. No other variables had significant interactions (p > 0.05). Conclusions: The present study confirms the hypothesis that chronic daily consumption of a multi-ingredient TRM will not cause adverse changes in hematological markers of clinical safety or resting vital signs in healthy adults. Although there were statistically significant (p ≤ 0.05) group by time interactions for diastolic blood pressure, creatinine, eGFR, chloride, CO2, globulin, albumin:globulin ratio, and HDL cholesterol, all of the results remained well within accepted physiological ranges and were not clinically significant. In sum, it appears as though daily supplementation with up to 2 servings of a TRM has no adverse effects on markers of clinical safety among healthy adults for a period of 28 days. Practical Applications: For healthy individuals or athletes looking to supplement to possibly help reduce body fat or mass, the multi-ingredient TRM in the present study appears to be safe for chronic consumption.
A Multi-Ingredient Purported Sleep and Recovery Enhancing Supplement Is Apparently Safe for Chronic Consumption in Healthy Males and Females
J. Joy,1 R. Vogel,2 P. Falcone,2 M. Mosman,2 A. Tribby,3 D. Lefever,3 S. McCaughey,3 M. Kim,2 and J. Moon2
1Concordia University Chicago/MusclePharm; 2MusclePharm; and 3MusclePharm Inc.
The practice of using multiple ingredients in sports supplements to increase the ergogenic effects of a single finished product is becoming more common. In certain cases, these ingredients interact to produce one synergistic effect, such as enhanced recovery following strenuous exercise. However, there may be unintended negative consequences of such interactions. Purpose: Therefore, the purpose of this investigation was to determine the safety of a multi-ingredient supplement (MIS) intended to aid restful sleep and enhance recovery of fatigued muscles. Methods: Forty-six recreationally-active adult males and females (23 males, 23 females, 26.9 ± 5.1 years, 170.0 ± 12.2 cm, 75.7 ± 18.1 kg) participated in this study. Participants were randomly assigned to consume either 1 (G1; n = 13) or 2 (G2; n = 13) servings daily of a commercially available MIS, or remain unsupplemented (CRL; n = 20) for a period of 28 days. All were instructed to maintain their habitual dietary and exercise routines for the duration of the study. Fasting blood samples, as well as resting blood pressure and heart rate, were taken before and after the supplementation period. Blood samples were analyzed for a complete blood count (red blood cells, white blood cells, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean corpuscular volume, hematocrit, hemoglobin, red blood cell distribution width, platelets, neutrophils, monocytes, eosinophils, lymphocytes, basophils, and immature granulocytes), comprehensive metabolic panel (serum glucose, blood urea nitrogen, creatinine, estimated glomerular filtration rate, blood urea nitrogen to creatinine ratio, sodium, potassium, chloride, calcium, carbon dioxide, total protein, albumin, globulin, albumin to globulin ratio, bilirubin, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase), and lipid panel (total cholesterol, high density lipoprotein, low density lipoprotein, and triglycerides). Results: Significant group × time (p ≤ 0.05) interactions were observed for heart rate, percent monocytes, serum sodium, and total carbon dioxide (Table 1). No significant interactions were observed for any other measures (p > 0.05). Conclusions: Resting heart rate decreased in both G1 and G2 relative to control, and no variables deviated from the accepted physiological reference range. Thus, 28 days daily supplementation with the MIS is apparently safe for both recreationally-active males and females in a dose up to 2 servings. Practical Applications: The MIS can be used by athletes and recreationally-active individuals for the possibility that the MIS will aid recovery and sleep without the fear of adverse health events. It is also a possibility that the MIS may have therapeutic potential in terms of resting heart rate, and further research is warranted.
Baker's Yeast Beta Glucan Supplementation Improves Mucosal Immunity: Implications for Preventing Lost Training Days?
B. McFarlin,1 A. Henning,1 E. Prado,1 A. Venable,1 J. Best Sampson,1 D. Hill,2 and J. Vingren2
1University of North Texas; and 2Applied Physiology Laboratory, University of North Texas
Strenuous exercise is known to suppress mucosal immunity for up to 24-hour, which can increase the risk of developing an upper respiratory tract infection. Such infections result in lost practice and performance time, which has implications for training effectiveness. While many dietary interventions have been used to combat post-exercise immune suppression, most have been ineffective. Recent evidence has suggested that a commercially-available form of baker's yeast beta-glucan may be useful as an immune-booster. Purpose: The purpose of this study was to determine the effect 10-days of supplementation with baker's yeast beta-glucan (BG) prior to a bout of immune suppressive exercise on mucosal immunity during recovery from exercise in recreationally active subjects. Methods: Subjects (N = 109) completed 60-minute of interval running after consuming either BG (250 mg·d−1) or a placebo (sugar pill, PL) for 10-days prior to each bout of immune-suppressive exercise (60 minutes of interval running in a hot, humid environment). Double blind procedures were used throughout the study. Saliva was collected using a salivette placed under the tongue at baseline (BASE), before exercise (PRE), immediately (POST), two- (2H), and four-hours (4H) after exercise. The salivette was kept in the mouth for 10-minute and then transferred to a specially designed freezer tube and frozen (−80° C) until analysis for salivary IgA and IgM using a multiplex kit (Millipore Milliplex). Data were analyzed using separate repeated measures ANOVAs and significance was set at. Results: BG supplementation was associated with an increase in salivary IgA compared to placebo (p = 0.007). The greatest differences between conditions existed at 2H and 4H, which correspond with the “open window” period for infection risk. Conclusions: These findings support other published research highlighting the efficacy of baker's yeast beta-glucan supplementation on mucosal immunity following a strenuous bout of exercise. Practical Applications: While previous research is not conclusive, a boost to mucosal immunity may reduce susceptibility to upper respiratory tract infection. During periods of intense training, supplementation with baker's yeast beta-glucan may prevent the loss of training days due to sickness. This benefit would be useful to athletes in a variety of sports.
Investigation of the Acute and Post Exercise Effects of Tart Cherry Concentrate on Salivary IgA
K. Moody,1 D. Bellar,1 C. Foret,1 G. Davis,1 N. LeBlanc,1 K. Murphy,1 and L. Judge2
1University of Louisiana at Lafayette; and 2Ball State University
Individuals who perform rigorous endurance exercise are more susceptible to contracting Upper Respiratory Tract Infections (URTI). It is therefore important to determine if nutrition has the potential to provide protection for these individuals. Purpose: This investigation sought to determined both the acute effects of a tart cherry concentrate on salivary immunoglobulin A (sIgA) and the effects on sIgA post-exercise. Methods: Thirteen college-aged apparently healthy males volunteered to participate in a single blind, repeated measure study (M ± SD, age = 21.24 ± 2.59 years). They were assigned to ingest either tart cherry concentrate in liquid form or placebo (cherry flavored water) for 6 consecutive days in the morning and evening in a cross over fashion. On the sixth day they cycled for 20 minutes at 70% of their V[Combining Dot Above]O2 Max. Saliva samples were taken 1 hour after the initial dose, and after the exercise on day 6 to quantify sIgA using a commercially available immunoassay. After a 1-week washout, the subjects repeated the protocol with the opposite treatment. Results: For the acute affects after the initial dose a repeated measures ANOVA did not reveal a significant (F = 1.13, p = 0.2998) main effect for treatment (Tart Cherry Concentration vs. Placebo). Similarly repeated measures ANOVA did not reveal a significant (F = 0.3295, p = 0.5724) main effect for treatment (Tart Cherry Concentration vs. Placebo) post exercise. Conclusions: The data demonstrated that tart cherry concentrate was not effective at acutely increasing sIgA or increasing sIgA after aerobic exercise. Practical Applications: Tart cherry concentrate cannot be recommended to enhance mucosal antimicrobial protein levels.
Safety of a Pre Workout Supplement in Healthy Individuals for a Twenty-eight Day Duration
M. Mosman,1 J. Joy,2 P. Falcone,1 R. Vogel,1 C. Hughes,3 J. Griffin,4 K. Paulin,5 M. Kim,1 and J. Moon1
1MusclePharm; 2Concordia University Chicago/MusclePharm; 3Grand Valley State University; 4Widener University; and 5University of Colorado
In recent years, the consumption of multi-ingredient supplements in the pre-exercise time period in order to obtain ergogenic benefits has become increasingly popular. Ingesting pre-workout supplement(s) (PWS) is one approach used by athletes and recreational populations to aid performance and maximize training adaptations. Purported benefits include increases in strength, improved focus, and sustained energy during exercise. While research exists on the ergogenic benefits of PWS, less is known regarding the safety and potential side effects of chronic consumption. Purpose: The purpose of this study was to examine the safety of consuming a PWS containing caffeine, nitrates, beta-alanine and amino acids over a 28 day period. Methods: 58 young males and females (26.7 ± 4.8 years, 173.3 ± 9.2 cm, 76.8 ± 18.0 kg) participated in this study. Subjects were equally and randomly assigned to consume either 1 (G1; n = 22) or 2 (G2; n = 18) servings daily of a pre-workout supplement or remain un-supplemented (CON; n = 22). Fasting blood samples (white blood cells, red blood cells, hemogloblin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, platelets, neutrophils, lymphocytes, monocytes, eosinophils, basophils, absolute neutrophils, absolute lymphocytes, absolute monocytes, absolute eosinophils, absolute basophils, immature granulocytes, absolute immature granulocytes, glucose, blood urea nitrogen (BUN), creatine (Cr), eGFR, BUN:CR ratio, sodium (Na), potassium, chloride, carbon dioxide, calcium, total protein, albumin, globulin, albumin:globulin ratio, bilirubin, alkaline phosphatase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, triglycerides, high density lipoprotein, and low density lipoprotein) along with resting blood pressure and heart rate were taken before and after the 28 day period. All groups were instructed to maintain and record their normal dietary and exercise habits and keep a supplementation and adverse event log for the duration of the study. Results: Repeated measures ANOVA revealed no significant interactions between groups (p ≤ 0.05) for all measures. Mean and SD for selected variables representative of heart, liver, and kidney function are presented in Table 1. All dependent variables remained within normal clinical reference ranges. No adverse events were reported in this study. Conclusions: Overall, the PWS appears to be safe in both 1 and 2 serving doses consumed daily for up to a 28 day period in healthy males and females.
A Commercial Bio-Active Peptide Dietary Supplement Increases the Rate of Strength Development With Eight Weeks of Resistance Training
Previous research efforts have indicated that supplementation with a commercial food-based bio-active peptide product may reduce the amount of recovery time needed between repeated bouts of strenuous exercise. It has been suggested that improved recovery from exercise may enhance chronic training adaptions, such as enhance muscular strength, compared with training without supplementation. Purpose: The primary purpose of this investigation was to examine the effects of 8 weeks of supplementation with a commercial bio-active peptide product on measures of muscular strength during a program of resistance training. Methods: Twenty men, with a mean age of 25.5 ± 3.8 years and classified as recreationally active (training at least 3 sessions per week), voluntarily participated in this study. All subjects participated in 4 resistance training sessions per week over the 8 week study period with all training sessions directly supervised by investigators. Participants were randomly assigned to one of 2 supplemental groups, Placebo (PL) or bio-active peptide product (BAP), in a double blind manner. Supplements were provided in powder form and mixed with water in 2 daily doses. Prior to and following the 8 week training period, participants underwent maximal strength testing (1RM) of upper and lower extremities, bench press and leg press, respectively. Change scores were determined based on pre- and post-training test values and compared between groups using 1-way ANOVA. Results: Supplementation with BAP during 8 weeks of intense resistance training produced significantly greater gains in both upper and lower extremity maximal strength compared with PL. The mean values of 1RM for bench press increased 16.5 ± 13.0 pounds with BAP which was significantly greater than the 4.0 ± 11.5 pound increase in maximal bench press exhibited by the PL group (p ≤ 0.05). The BAP group also displayed significantly greater gains in maximal leg press (118.0 ± 68.9 pounds) compared with a 54.5 ± 51.5 pound mean increase with PL (p ≤ 0.05). Conclusions: When applied in conjunction with an 8 week program of resistance training, dietary supplementation with a commercial BAP product produced significantly greater gains in upper and lower extremity maximal strength levels compared with training with PL. Practical Applications: As maximal strength levels are known to be primary determinants of performance of many sports activities, these findings may have implications when participating in resistance training in a variety of settings. Strength and conditioning professionals should be aware that food based bio-active peptides appear to provide a supplementation option that may increase the rate of strength improvement of both upper and lower extremities with relatively intense resistance training.
Could a Theoretical Change in Geographical Location Influence the Precision of Athlete Lower Body Jump Capacity Monitoring
D. Chapman1 and J. Sheppard2
1Australian Institute of Sport; and 2Surfing Australia
Commonly in sports institutes, universities and well resourced professional sporting teams a force plate or linear position transducer is the tool of choice to monitor lower body jumping capacity due to the precision of measurement, thus improving decision making certainty. However, use of these commercial devices in accordance to and with proprietary software does not include the functionality to precisely determine a specific acceleration due to gravity based on a geographical location; instead the gravity constant is pre-programmed. However gravity is not constant and where teams train and compete at altitude this change in gravity constant may adversely impact the ability to effectively monitor an athlete's physical capacity or readiness to train. Purpose: To compare static force values from known weights with theoretical values and then provide comment on any observed differences between known and theoretical values compared to a smallest worthwhile change (SWC) scores in common monitoring jump tasks, i.e., countermovement jump. Methods: Using a commercially available portable force plate and operating software we calibrated and zeroed the force plate as per the manufacturer instructions and then preceded to divide the top surface into 9 equal segments. Calibrated masses were added to the first segment beginning with 40 kg and increasing by 10 kg until 240 kg was reached. For each weight a 2 seconds static force trace was recorded and saved. Prior to the next 10 kg increment the previous weight was removed, force plate zeroed and the next weight added up to 240 kg. This procedure was repeated through to the completion of 9 segments. The peak force plate recorded values were compared to theoretical values, which were determined using the known weight and a gravitational constant for the geographical location, (9.795 milliseconds−2). Comparisons between loads (40–240 kg) and outcome measures (recorded versus theoretical) were made with a 2-way repeated measure ANOVA. The percentage in the change score was calculated comparing the measured values with the theoretical values. This comparison required the standard deviation of the mean for each mass to be derived using:
. Values with a percentage change score greater than the SWC (2.5% variation equivalent to >50 Nm) for a countermovement jump would be deemed outside of acceptable. Results: There was no linearity drift between the 9 segments. A significant interaction effect between the weight and force was identified; subsequent Bonferroni post hoc revealed weights 70–120 kg (p ≤ 0.05) and 130–240 kg (p < 0.001) differed significantly between recorded and theoretical. The difference between recorded and theoretical as a percentage was greater than SWC at any weight ≥70 kg. Conclusions: The use of the standard gravity acceleration constant leads to incorrect force values, which could lead to compounded errors in other derived variables. The magnitude of the force error due to an incorrectly applied gravity constant is greater than the accepted value of smallest worthwhile change in force produced in a countermovement jump. Practical Applications: It is the authors' opinion that the monitoring of athletes when in situations where you travel to a location that is of a different altitude to your normal monitoring location is unduly compromised by the use of incorrect gravity constants in force, velocity and power calculations due to the magnitude of difference between them.
Modality-Specific Changes in Upper-Body Muscular Strength Are Independent of Fat-Free Mass in Untrained College Women
W. Brechue,1 J. Mayhew,2 J. Arabas,2 and C. Kerksick3
1A.T. Still University; 2Truman State University; and 3Lindenwood University
Recent research indicates that machine weights produce greater upper-body strength gains than free weights in women regardless of initial level of strength. Yet to be explored is the effect of initial body composition on modality-specific improvement in strength. Purpose: To compare the effect of resistance training with free weights and machine weights on upper-body strength in untrained women with differing levels of FFM at training inception. Methods: Untrained women (N = 325) were assigned to a low FFM (LM, n = 81), average FFM (AM, n = 163), or high FFM (HM, n = 81) groups based on the 25th and 75th percentiles of FFM and measured with free weights (FW, n = 155) or a supine vertical press (SVP, n = 170). Body composition was estimated from a 3-site gender-specific equation. Training was conducted 3 times per week for 12 weeks using a linear periodization program of increasing loads and decreasing repetitions. In addition, subjects performed 3 sets with their 10RM for supplemental arm and leg exercises during each training session. Results: Prior to training, a MANOVA indicated that age, height, body mass, FFM, and %fat were not significantly different between modality groups. Height, weight, FFM, and %fat were significantly different by FFM group (HM > AM > LM) with no significant interactions. There was a tendency (p = 0.06) for the FW group (0.9 ± 1.8 kg) to gain more FFM than the SVP group (0.5 ± 1.9 kg) without changes in %fat. Following training, the increase in 1RM and 1RMper kilogram FFM was significantly greater in SVP (6.4 ± 4.0 kg, 0.13 ± 0.09, respectively) than in FW (5.3 ± 4.0 kg, 0.09 ± 0.08, respectively). The increase in 1RM following training was not different among FFM groups (LM = 5.6 ± 3.9 kg; AM = 6.1 ± 3.9 kg; HM = 5.8 ± 4.6 kg). Relative FFM gain was similar (p > 0.06) among FFM groups (LM = 1.7 ± 2.9%; AM = 1.5 ± 3.9%; HM = 0.6 ± 3.8%). 1RM per kilogram FFM was unaltered by training (LM = 0.12 ± 0.10 kg; AM = 0.09 ± 0.09 kg; HM = 0.9 ± 0.08 kg). There were no significant mode × FFM level interactions for strength. Conclusions: Untrained women appear to experience greater increases in upper-body muscular strength when utilizing a machine weight as opposed to free weights. Furthermore, initial FFM does not influence the degree of absolute or relative upper-body strength gain. Practical Applications: Previously untrained women may gain more strength initially utilizing machine weights as a resistance training mode. Strength gains appear to be independent of initial FFM levels.
Predictive Accuracy of 3–4RM, 5–6RM, and 7–10RM to Estimate 1RM Bench Press in Untrained College Women
K. Lovegreen,1 J. Arabas,1 W. Brechue,2 and J. Mayhew1
1Truman State University; and 2A.T. Still University
Previous studies indicate that various combinations of submaximal load and repetitions can estimate 1RM in women with reasonable accuracy. Several studies suggest that a lower repetition range offers slightly better predictive accuracy. However, limited information appears available on use of fixed loads as predictors of 1RM performance. Purpose: To assess the predictive accuracy of the 3–4RM, 5–6RM, and 7–10RM to estimate 1RM bench press performance in untrained women. Methods: 215 untrained college women were tested for 1RM free-weight bench press and body composition via skinfold-prediction. One week later, they self-selected a repetition load (RepWt) that allowed between 3 and 10 repetitions to fatigue (RTF). Participants were stratified into groups (3–4RM, n = 52; 5–6RM, n = 51; and 7–10RM, n = 112) based on their RTF performance. Low strength (LS, n = 108; 1RM/BM0.66 = 1.67 ± 0.20) and high strength (HS, n = 107; 1RM/BM0.66 = 2.40 ± 0.44) groups were formed by dividing the sample at the median. One repetition maximum was predicted using a %1RM equation
Results: A multivariate ANOVA indicated that the 7–10RM group was significantly older, heavier, had higher fat-free mass (FFM) and greater BMI than the 3–4RM and 5–6RM groups which were not significantly different in those characteristics. None of the repetition groups differed significantly in %fat. The LS group was significantly taller, heavier, had a greater FFM, BMI, and %fat that the HS group. None of the interactions were significant. When the difference between predicted 1RM and actual 1RM was considered, the 3–4RM group (−1.4 ± 2.9 kg) was significantly lower than the 5–6RM (0.5 ± 2.9 kg) and 7–10RM groups (1.5 ± 4.3 kg). The LS (0.7 ± 3.1 kg) and HS (0.2 ± 4.5 kg) groups were not significantly different, and the repetition × strength group interaction was not significant. The relationship between predicted and actual 1RM was slightly lower for the 3–4RM group (ICC = 0.918) than the 5–6RM (ICC = 0.959) and 7–10RM groups (ICC = 0.950). The relationship between predicted and actual 1RM was slightly lower for the LS group (ICC = 0.924) than for the HS group (ICC = 0.937). The percent difference between predicted and actual 1RM was not significantly related to body mass, BMI, or fat-free mass (r = −0.04 to 0.09). Conclusions: A medium-level repetition range load (5–6RM) was slightly better for estimating 1RM bench press in untrained college women. Strength level does not seem to exert an influence on prediction of 1RM from repetition load in young women. Practical Applications: A RepWt that produces between 3 and 10 RTF appears able to produce an estimated 1RM bench press in untrained women with an average error of 1.3% (±11.5%).
Allometric Scaling of Bench Press Performance in Young Men and Women
G. Leahy,1 K. Lovegreen,2 J. Mayhew,2 and W. Brechue3
1Veterans Administration; 2Truman State University; and 3A.T. Still University
Ratio strength measurements have been used for some time in an attempt to equate maximal strength values among individuals of different size. Allometric scaling has been proposed as a more equitable way of comparing groups for muscular strength due to the nonlinear relationship of body mass to strength. Purpose: To evaluate the use of allometric scaling techniques for assessing the differences between genders in 1RM bench press performance. Methods: Untrained college men (n = 720, age = 19.4 ± 1.3 years, weight = 76.5 ± 14.7 kg) and women (n = 697, 18.8 ± 0.9 years, weight = 63.0 ± 12.1 kg) enrolled in a required wellness course were evaluated for 1RM bench press using free weights and body composition using skinfolds. Skinfolds were measured at the chest, abdomen, and thigh in men and at the triceps, suprailium, and thigh in women. Body composition was estimated using gender-specific generalized equations. Bench press was evaluated using a ratio standard and allometrically scaled for body mass (BP/BMk) and fat-free mass (BP/FFMk). Results: The correlation of BP with FFM was significantly higher than for BP with BM in both men (r = 0.58 and 0.48, respectively) and women (r = 0.60 and 0.44, respectively). Log-transformed linear regression revealed that neither of the coefficients for gender nor gender × lnBM were significant (p > 0.08), indicating that the common exponent principle was upheld. The common exponent for scaling BP by BM was 0.73 (95% CI = 0.66–0.80), which produced nonsignificant correlation between body mass and the scaled BP value for men (r = 0.06) and women (r = 0.01). Since the CI for the common exponent for BM includes the theoretical 0.67 value, BP was scaled by that coefficient which produced a non-significant correlation between body mass and the scaled BP value for women (r = 0.05) but a significant relationship for men (r = 0.10). The coefficients for gender and gender × lnFFM were significant (k) was much greater for men (1.07 ± 0.25 vs. 0.42 ± 0.10, respectively) than for women (0.68 ± 0.15 vs. 0.58 ± 0.15, respectively). Conclusions: Men were approximately 1.8 times stronger than women when compared by absolute BP and 1.9 stronger when BP is scaled by body mass (BP/BMk). However, women were 1.5 times stronger than men when BP is scaled by BP/FFMk. Practical Applications: It appears that men are stronger than women when considered by either a ratio standard or an allometric standard for BM, however, women appear stronger when using an allometric scaling to FFM. The use of FFM may provide more physiologically relevant comparison between genders, but further analysis to isolate upper- and lower-body lean masses seems warranted due to the difference in distribution of muscle masses between the genders.
Influence of Different Models of Periodization on Strength and Flexibility Gains in Adolescents
R. Souza, E. Moraes, R. Simão, C. Bentes, and H. Miranda
Federal University of Rio de Janeiro
Strength training (ST) when properly designed and supervised is safe for children and adolescents and may increase the strength levels to prevent injuries in daily activities to recreational sports. Purpose: To compare the influence of different models of periodization of ST in strength and flexibility levels in upper limbs in adolescents after 12 weeks of training. Methods: Fifty male adolescents (age, 15.3 ± 0.9 years; tanner, 3.34 ± 0.4; height, 169.9 ± 8.7 cm; weight, 62.5 ± 7 9 kg; BMI, 21.6 kg·m−2) physically active and no previous experience in ST, were randomly assigned to 1 of 4 groups: GC-control group did not follow the ST; NP-non-periodized group; PL-linear periodized group; PNLD-daily nonlinear periodized group. Frequency of training was 3 times per week, total of 36 sessions with 4 upper limbs exercises, intensity and volume of repetitions were determined with a timeline for the PL and PNLD groups, while the NP group performed 3 sets of moderate intensity (10–12RM). The strength (bench press 1RM) and the flexibility (articular movements by goniometry—shoulder flexion [SF] and extension [SE], horizontal shoulder adduction [SAD] and abduction [SAB]) were verified before and after 12 weeks. The data analyses was accessed by the multifactorial 2 × 3 mixed ANOVA with a post hoc of Tukey, with a per-comparison alpha level of p ≤ 0.05. Results: There is a significant increase in intra-group analyses (before and after) in upper limbs strength assessments only in PL and PNLD, moreover no differences were verified between groups. In flexibility assessments were verified significant increases (before and after): NP-SAD; PL-SF, SE, SAD; PNLD-SF, SE, SAD, SAB (Table 1). Conclusions: Periodized strength training promotes increase on strength and flexibility in adolescents, this did not occur with NP training. Practical Applications: Our findings indicate that the periodized strength training must be used to promote more significant gains in strength and flexibility in adolescents than no periodized strength training.
A Comparison of Methods to Compare Quantification of Training Loads During Collegiate American Football Practice
G. Wright,1 D. Trautman,2 A. Snyder,2 K. Schwab,2 J. Smith,2 M. Meinking,3 K. Schultz,2 and J. Dettwiler2
1University of Wisconsin-La Crosse; 2University Wisconsin-La Crosse; and 3University Wisconsin-La Crosse
Introduction: The monitoring of training load (TL) during sport practice is performed to provide coaches with knowledge about absolute and relative dose of training through a season and to compare to actual game day workloads. Previous research has used internal measures of TL's such as rating of perceived exertion (RPE) and various methods based on training impulse (TRIMP) using heart rate (physiological load). Recent research has used accelerometers and global positioning systems (GPS) to determine external load based on the intensity and volume of movement during training (mechanical load). However, monitoring external TL with this type of equipment is expensive. The use of session RPE to calculate RPE load (RPE × duration in minutes of training) and physiological load based on heart rate are comparatively less expensive. Purpose: To compare various measures of TL derived from mechanical (accelerometer), physiological (heart rate), and perceptual (RPE) data during preseason American football practice sessions. Methods: Twelve Division III collegiate football players (21.3 ± 1.4 years, 185.8 ± 6.5 cm, 104.2 ± 18.4 kg) were monitored during 17 preseason practices over 14 consecutive days. Mechanical and physiological loads were determined by a device worn on a chest strap that measured accelerometry and heart rate simultaneously over the duration of each practice. Session RPE was recorded within 30 minutes following practice and multiplied by the duration of practice. Relationships were determined by Pearson product moment correlations. Results: Strong correlations were observed between RPE load and mechanical load (r = 0.55, p < 0.001) and RPE load and physiological load (r = 0.59, p < 0.001). In addition, very strong correlations were observed between mechanical load and physiological load (r = 0.70, p < 0.001). Conclusions: Although each of the different TL's are determined by different constructs, internal and external TL's are strongly related for collegiate football players during practice. Practical Applications: Coaches and sport scientists can monitor training load using either method of internal TL (RPE or physiological) when the expense of external load monitoring equipment is a limiting factor. The very strong correlation between mechanical load and physiological load as calculated in this study indicates physiological load may provide more meaningful data compared to RPE load in college football players during practice.
Effect of Resistance Training on Strength and Power Is Not Different Between 1 Day and 2 Days per Week if Total Training Volume Is Equated
K. Shibata,1 K. Takizawa,2 and M. Mizuno3
1Graduate School of Education, Hokkaido University; 2Research Division of Lifelong Learning, Institute for the Advancement of Higher Education, Hokkaido University; and 3Faculty of Education, Hokkaido University
Introduction: As for the frequency of resistance training, it is said that 2 times per week is appropriate. Some studies showed that 1 session per week is effective to maintain strength, and is inferior to multiple times per week to increase rate of strength. However, there are few studies that compare 1 day with multi days per week with equated total training volume. Effect of resistance training that performed 1 day per week with double volume and 2 days per week is not clear. Purpose: The purpose of the present study was to compare between 1 day and 2 days per week of resistance training with equated volume on muscle strength and power. Methods: Fourteen university tennis players (mean ± SD age = 20.1 ± 0.7 years; body mass = 68.3 ± 13.2 kg; height = 173.5 ± 5.5 cm) participated in this study. They were assigned to 1 day per week group (1-DAY; n = 7) or 2 days per week group (2-DAY; n = 7). They performed squat at 90% 1 RM for 6 weeks. 1-DAY group performed resistance training once per week and 8 sets per session. 2-DAY group performed 2 days per week and 4 sets per session. Before (PRE) and after (POST) the training period, 1RM and power at 30–90% 1RM of the squat were measured. Muscle soreness after first or second resistance training was measured by Visual Analogue Scale (VAS). Results: There was no interaction effect in 1RM (1-DAY, PRE = 107 ± 12 kg, POST = 114 ± 13 kg; 2-DAY, PRE = 111 ± 28 kg, POST = 118 ± 25 kg) and power at each load of the squat. There was significant main effect for time in 1RM (p < 0.01) and power at each load (p ≤ 0.05; Table 1) of the squat. Peak muscle soreness after first or second resistance training was significantly higher (p ≤ 0.05) in 1-DAY group (6.2 ± 2.3 cm) than 2-DAY group (2.9 ± 1.9 cm). Conclusions: The effect of 6 weeks of 1 day or 2 days per week of resistance training on muscle strength and power is not different if total training volume was not different. However, peak muscle soreness was higher in 1-DAY group. Practical Applications: If athletes cannot secure resistance training 2 times per week, they had better perform resistance training for double volume at once a week to increase strength and power. However they need to pay attention when they do practice and other exercises because peak muscle soreness was higher in the group which performed double volume per session.
Adaptations of Achilles and Patellar Tendons in Chronically Resistance-Trained Men and Moderately Active Men
B. Comstock,1 M. Joseph,2 C. Denegar,2 J. Volek,3 C. Maresh,3 S. Flanagan,3 J. Pryor,2 A. Sterczala,4 D. Hooper,3 W. DuPont,3 T. Szivak,3 M. Beeler,1 and W. Kraemer3
1University of South Dakota; 2University of Connecticut; 3The Ohio State University; and 4The University of Kansas
Chronic resistance training is a whole body stimulus and can cause adaptations in skeletal muscle, bone, and tendon. Lean body mass and bone mineral density increases are expected with training, yet it is unclear how tendons adapt to resistance training. Purpose: The primary purpose of this study was to examine patellar and Achilles properties (stiffness, Young's Modulus, and cross-sectional area [CSA]) between resistance-trained men (RT) and non-resistance trained young men (NR). A secondary purpose of this study was to compare body composition (lean body mass, LBM; bone mineral density, BMD) between the groups. Methods: Thirteen young men who regularly resistance trained, utilizing multiple joint, large muscle group exercises (age: 22.2 ± 1.4 years; 6.5 ± 1.9 years of training experience; 2.0 ± 0.3 1RM/BM ratio) and 13 young men (age: 22.8 ± 2.2 years), who were moderately active, yet did not resistance train, participated in this investigation. A cross-sectional design, was used to compare patellar and Achilles cross-sectional area (CSA), stiffness, and Young's modulus from simultaneous ultrasound imaging and force recordings of a ramp isometric contraction protocol. Additionally, dual x-ray absorptiometry was used to compare LBM and BMD between the groups. Results: The patellar tendons of trained men were 45% stiffer (RT: 3,011.0 ± 1,414.2 N·mm−1, NR: 2074.1 ± 861.1 N·mm−1; p = 0.052, 95% CI [L,U] = −10.9, 1884.7), had 36% greater Young's modulus (RT: 1.19 ± 0.28 GPa, NR: 0.88 ± 0.13 GPa; p = 0.001, 95% CI [L,U] = 0.14, 0.49), and larger CSA, using magnitude-based inference (RT: 119.7 ± 12.8 mm, NR: 113.8 ± 9.0 mm; p = 0.179, 95% CI [L,U] = −2.9, 14.9). Achilles tendons of trained men were larger in CSA (RT: 63.4 ± 6.6 mm, NR: 57.5 ± 7.5 mm; p = 0.044, 95% CI [L,U] = 0.2, 11.7), yet similar in stiffness (RT: 220.5 ± 34.7 N·mm−1, NR: 205.2 ± 44.5 N·mm−1; p = 0.339, 95% CI [L,U] = −17.0, 47.5) and modulus (RT: 213.0 ± 32.4 MPa, NR: 224.2 ± 52.5 MPa; p = 0.518, 95% CI [L,U] = 46.6, 24.1). As expected, trained men possessed greater lean body mass (LBM) and bone mineral density (BMD) than moderately active men (LBM: 71.4 ± 5.6 kg, 59.1 ± 5.8 kg, respectively, p ≤ 0.01; BMD: 1.37 ± 0.1 g·cm−2, 1.28 ± 0.1 g·cm−2, respectively, p ≤ 0.01), while fat mass (FM; RT: 15.8 ± 5.8 kg, NR: 13.4 ± 5.4 kg) was similar between the groups. Conclusions: These findings show trained men had distinctly different skeletal muscle, bone, and tendon tissues than non-resistance trained men, indicating benefits of chronic resistance training, beyond that of a moderately active lifestyle. Furthermore, patellar and Achilles tendons respond differently to chronic resistance training. One explanation of these differences could reside in the role of soleus, and the entire triceps surae muscle group, in closed chain exercises such as the deadlift and squat. Typical exercise technique suggests that plantar flexion is not advantageous for performance of these lifts, and the muscles and tendons involved are largely used for stabilization. These adaptations are likely specific to the forces these tendons are exposed to within activities of everyday life, and the traits of resistance training program used, namely the Acute Program Variables. Practical Applications: When programming resistance training for a variety of populations (either trained or untrained), the primary focus is usually on muscular adaptations (e.g., strength, power, or hypertrophy). This study shows that other musculoskeletal tissues, namely tendon and bone are responsive to chronic, multijoint, heavy resistance training, and should also be considered when programming training for both performance enhancement and injury prevention. Further, the major tendons of the lower body adapt differently to chronic resistance training, which is likely due to traits of the exercises and training program used.
Inter-Investigator Reliability for Anthropometric Variables on Prediction of %Fat and 1RM Bench Press
J. Mayhew,1 R. Schumacher,1 J. Arabas,1 and W. Brechue2
1Truman State University; and 2A.T. Still University
One repetition maximum lifts (1RM) are the major method of evaluating strength performance of college football players. Several non-performance approaches to identifying maximal strength potential of players have employed various anthropometric dimensions. However, variations in measurement technique among testers might also be a factor in the accuracy of various anthropometric predictions of strength performance. Purpose: To determine the effect of inter-investigator different in anthropometric assessment on the prediction of 1RM bench press. Methods: Division-II college football players (n = 34, age = 20.4 ± 1.2 years, 182.3 ± 6.6 cm, 99.1 ± 18.4 kg) volunteered to be measured for 1RM bench press at the conclusion of a 10-week winter heavy resistance training program. In addition, skinfolds were measured in triplicate by 3 investigators at the triceps, subscapular, and abdominal sites and used to estimate %fat from the Lohman formula. Muscle circumferences were measured around the flexed arm and relaxed chest. Arm circumference corrected for triceps skinfold was used to estimate arm muscle cross-sectional area (CSA). Results: Significant differences among the testers were evident in 6 of the 9 anthropometric variables, with the tester with the least experience significantly different from the remaining testers on 7 variables. The 2 more experienced testers were significantly different on only 2 variables. The average difference among investigators ranged from 4 to 9% for skinfolds and 1–2% for circumferences. Flexed arm circumference was the only variable where all 3 testers differed significantly. However, the agreement among testers was considered high (ICC > 0.895) for each variable and further supported by low coefficients of variation (CV < 10.7%). Conclusions: Individuals with varying degrees of experience appear to have an acceptable level of ability to estimate 1RM bench press using a non-performance equation. Practical Applications: Minimal experience in anthropometry might allow strength and conditioning specialists to estimate maximal bench press strength potential within ±13% of actual 1RM in 68% of a team's players.
Assessment of the Learning Effect With Repeated Isometric Strength Testing at Two Knee Joint Angles
W. Holcomb,1 C. Bremner,1 C. Brown,2 and M. Miller3
1University of Southern Mississippi; 2The University of Southern Mississippi; and 3Western Michigan University
A learning effect with isometric testing where force production increases from one testing session to the next has been well documented. To get a true measure of isometric strength it is recommended that subjects become familiar with the test prior to data collection, particularly for pre/post-test designs where apparent strength gains may result from learning the test. Purpose: In situations where maximum voluntary isometric contractions (MVIC) are used to normalize data, the learning effect may be of less concern. Therefore, the purpose of our study was to assess the magnitude of the learning effect by comparing torque during MVIC on 3 test days at 2 knee joint angles. Methods: Fourteen healthy females (height = 163.6 ± 5.4 cm, mass = 70.3 ± 16.2 kg, age = 21.4 ± 2.5 years) participated. A standard warm-up was performed before testing each day. Isometric actions were performed on a calibrated dynamometer with the knee in 60° or 15° of knee flexion. Participants performed 3 repetitions of 10 seconds duration of MVIC at each of the knee joint angles (60° and 15°). Each repetition was separated by a 2-minute rest period. For MVIC, participants were instructed to extend the knee against the fixed lever arm with maximum force. The same methods were used for measuring force during MVIC on each of the 3 test days. The test order for the 2 joint angles was counterbalanced. The highest peak torque means and average peak torque means at 60° and 15° were compared using 2 separate one-tailed dependent t-tests for day 3. Mean highest peak torque and average peak torque at 60° and 15° over days 1, 2, 3 were analyzed using 4 separate repeated measures ANOVA (α = 0.05). Results: There was a significant difference (t13 = −13.388, p < 0.001) between the highest peak torque at 60° (148.4 ± 30.8 N·m) compared to the highest peak torque at 15° (67.2 ± 14.3 N·m). There was a significant difference (t13 = −13.701, p < 0.001) between the average peak torque at 60° (137.4 ± 27.4 N·m) compared to the average peak torque at 15° (64.5 ± 13.7 N·m). There was no significant difference in highest peak torque between days 1 and 3 at 60° or at 15°. Highest peak torque means for days 1–3 at 60° were 136.7 ± 25.7 N·m, 140.2 ± 27.9 N·m and 148.4 ± 30.8 N·m, respectively. Highest peak torque means for days 1, 2 and 3 at 15° were 63.8 ± 14.1 N·m, 63.8 ± 11.8 N·m, and 67.2 ± 14.3 N·m, respectively. Similarly, no significant differences in average peak torque were observed between days 1 and 3 at 60° or at 15°. Average peak torque means for days 1–3 at 60° were 123.2 ± 24.8 N·m, 132.8 ± 29.1 N·m and 137.4 ± 27.4 N·m, respectively. Average peak torque means for days 1–3 at 15° were 59.7 ± 12.7 N·m, 60.3 ± 11.0 N·m, and 64.5 ± 13.7 N·m, respectively. Conclusions: Force values were greater at 60° compared to 15° which was expected due to the length tension relationship and there appears to be no significant learning effect over the 3 days of testing for either peak or average torque. Practical Applications: There was no significant difference in peak or average torque for 60° or 15° over time. Thus, when using MVIC for the sole purpose of normalizing data, familiarization sessions may not be necessary. However, because the mean scores increased slightly from days 1–3 for all conditions, additional familiarization days may result in a significant learning effect. Therefore, additional familiarization days should be examined with isometric testing especially when the variable of interest is pre/post-test isometric strength gains.
Thursday Abstract Posters Presentations—Session B
Thursday, July 09, 2015, 3:00 PM–4:30 PM
Dietary Practices for Injured Cadets in the Texas A&M Corps of Cadets
C. Goodenough,1 G. Darling,1 J. Carter,1 H. Hopkins,1 S. Currenti,1 N. Ono,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: Subpar nutrition decreases performance and increases the chance for injury. Emphasis should be placed on nutrition to promote recovery, immunity, and performance. Purpose: To investigate the dietary practices of injured cadets for the Texas A&M Corps of Cadets (CoC). Methods: When a cadet would miss physical training (PT) as a result of an injury or illness, he or she would complete a questionnaire that assessed their dietary practices. Results: 71.6% of the cadets felt their diet was adequate to meet their training needs. However, only 17.6% of the cadets reported eating breakfast prior to morning PT, with 23.0% indicating that they did not drink fluids prior to morning PT. 47.3% of the cadets found it difficult to eat within 1–2 hours before training. However, 78.4% found it easy to eat within 1–2 hours following training. 26.5% indicated that their last meal prior to becoming injured was 8–10 hours earlier. 51.4% of the cadets were trying to lose weight, whereas 18.9% were trying to gain weight. Of the injured, 35.1 and 58.1% reported taking some form of nutritional supplements and multivitamin, respectively. The most common supplements included whey protein, fish oil, multivitamins, and vitamin C. Using independent samples T-Tests, there was a significant difference (p ≤ 0.05) between upper classmen (UC) and freshmen (FM) (UC, 1.8 ± 0.8; FM 2.5 ± 0.8) for their confidence in their dietary practices. Conclusions: The cadets should be educated on optimal nutrition for their training needs, especially regarding hydration prior to morning PT. Practical Applications: Proper nutrition does not guarantee success; however, improper nutrition guarantees suboptimal performance. FM, who acquire the most injuries, are not as confident in their dietary practices compared to UC. Therefore, emphasis should be placed on educating the FM prior to engaging in the CoC PT. Future research should look at the dietary practices of the non-injured cadets compared to the injured cadets to determine if differences exist.
The Effects of a Multi Ingredient Performance Supplement on Anthropometric Measures and Resting Metabolic Rate in College Aged Individuals
J. Gray,1 K. Shields,2 R. Lowery,2 M. Sharp,2 J. Lane,1 C. Hollmer,2 J. Partl,1 D. Hayes Jr,1 J. Minevich,1 J. Rauch,1 E. de Souza,1 and J. Wilson1
1University of Tampa Human Performance Laboratory; and 2University of Tampa Human Performance Lab
Purpose: Conjugated Linoleic Acid (CLA) supplementation has been shown to be effective in decreasing fat mass in individuals. In addition to body composition research, recent studies have peaked interest on CLA's potential effects on Respiratory Exchange Ratio and Total Calorie Expenditure. Currently, limited information exists on the supplementation of CLA in combination with pomegranate and Bioperine on anthropometric and metabolic measures in humans. Therefore, the purpose of this study was to examine the effects of a multi ingredient supplement (BellyTrim XPTM) on anthropometric measures, Respiratory Exchange Ratio, Resting Metabollic Rate, and predicted V[Combining Dot Above]O2 Max tests in college-aged individuals. Methods: Ten recreationally active, healthy individuals (total body mass 69.2 ± 10.2 kg) participated in this double-blind, placebo controlled study. Subjects consumed either 2 servings of 2 multi ingredient supplement (MIS) capsules (2.4 g) containing (1,200 mg of CLA, Pomegranate seed Oil [400 mg], and BioPerine [5 mg]) or Placebo (cornoil) for 7 days, followed by a 7 days washout period, then crossover to the other condition for 7 days. Dual-energy X-ray absorptiometry (Hologic, Boston, MA, USA) was used to measure body composition. Respiratory Exchange Ratio (RER), Resting Energy Expenditure (REE), and Oxygen Consumption (V[Combining Dot Above]O2) were measured through the MOXUS Metabolic Cart (AEI Technologies, Pittsburgh, PA). Measurements were taken at days 0 (baseline), 8, 18 and 26. Results: Repeated-measures analysis showed a significant group × time interaction for RER following the supplementation (p < 0.02) while the placebo group did not change (p > 0.05). The MIS group demonstrated a larger ES for RER when compared to placebo group (−1.20 vs. 0.29). No significant differences among the groups were observed in lean body mass, fat mass, total energy expenditure, or oxygen consumption. Conclusions: In our current study, the combination of CLA with pomegranate and bioperine did not impact LBM, FM, V[Combining Dot Above]O2 Max, or Resting Energy Expenditure over a short 7 day period. However it did increase fat oxidation. Practical Applications: CLA in combination with pomegranate and bioprene can be used acutely to increase fat metabolism.
Acute Effects of a Mushroom Blend on Oxygen Kinetics, Peak Power, and Time to Fatigue
K. Hirsch,1 E. Roelofs,1 E. Trexler,1 M. Mock,1 and A. Smith-Ryan2
1University of North Carolina at Chapel Hill; and 2University of North Carolina
Pre-workout blends containing cordyceps militaris may be beneficial for enhancing aerobic and anaerobic performance by improving oxygen kinetics and delaying fatigue. Cordyceps has been used in pre-workout supplement blends, but with little data on this ingredient as an acute ergogenic aid. Purpose: To determine the acute effects of a mushroom blend vs. placebo on oxygen kinetics, aerobic power, time to fatigue, and lactate levels during high-intensity exercise. Methods: In a randomized, double-blind placebo controlled design, recreationally active subjects (n = 28; mean ± SD; Age = 22.7 ± 4.1 years; Height = 175.4 ± 8.7 cm; Weight = 71.6 ± 12.0 kg) were assigned to one of 2 treatment groups: mushroom (MR; n = 13) or placebo (PL; n = 15). All subjects completed 3 baseline testing sessions (maximal oxygen consumption [V[Combining Dot Above]O2max], 6 minutes cycle, 3 minutes all-out cycle) separated by at least 24 hours. Respiratory gas analysis was used to determine V[Combining Dot Above]O2max, time to exhaustion (TTE), and ventilatory threshold (VT) during a maximal graded exercise test performed on a cycle ergometer. Lactate and oxygen saturation (SPO2) were measured at 0, 2, 3, and 6 minutes during a 6 minutes oxygen kinetics test at a workload 60% between VT and V[Combining Dot Above]O2max. Peak power output (PP) was recorded during the all-out 3 minutes cycle test with a resistance of 4.5% of body weight. Supplementation was given in capsules containing either 1.3 grams of mushroom blend, or 1.3 grams of maltodextrin (PL) taken orally in 3 divided doses (4 grams daily) for 1 week. The same 3 exercise tests were repeated following the 1-week supplementation period. Results: There was no significant time × treatment interaction for V[Combining Dot Above]O2max (p = 0.364) or TTE (p = 0.721) and no main effect for treatment for V[Combining Dot Above]O2max (p = 0.822) or TTE (p = 0.721). There was a main effect for time for both V[Combining Dot Above]O2max (p = 0.011) and TTE (p = 0.046) with increases in V[Combining Dot Above]O2max observed in both MS (47.7 ± 4.8 to 49.0 ± 4.8 ml·kg−1·min−1) and PL (46.4 ± 4.5 to 48.9 ± 4.3 ml·kg−1·min−1). In MS, 95% confidence intervals demonstrated a significant 3% increase in TTE (+28 seconds; 855.1 ± 106 to 883.2 ± 88.9 seconds). No significant changes in VT were observed (p > 0.05). Lactate increased significantly over the 6 minutes test in both groups with no significant difference between groups (p = 0.369). Although not statistically significant (p > 0.05), PP increased by 17.6% (539 ± 113 to 635 ± 395 W) in MS while PP decreased by 11.8% (645 ± 339 to 568 ± 197 W) in PL. Conclusions: Acute supplementation of a mushroom blend at 4 grams per day may augment PP during high-intensity anaerobic exercise. Practical Applications: There are few supplements that have significant ergogenic effects on performance following acute supplementation. A mushroom blend containing cordyceps militaris may be an effective method for improving anaerobic power by delaying fatigue. The ability to maintain peak power during high-intensity exercise could have positive implications for maintaining and improving training volume in athletes.
The Effects of a Multi-Ingredient Performance Supplement on Body Composition and Performance in NCAA Athletes
J. Minevich,1 R. Lowery,2 J. Volkommer,3 M. Lovell,3 K. Shields,2 M. Sharp,2 C. Hollmer,2 E. de Souza,1 and J. Wilson1
1University of Tampa Human Performance Laboratory; 2University of Tampa Human Performance Laboratory; and 3The University of Tampa
Proteins provide the building blocks of skeletal muscle via their constituent amino acids. Athletes consume supplementary amino acids to repair and rebuild skeletal muscle for faster recovery following intense training bouts. Previous research indicated that supplementing with the leucine metabolite, hydroxy-isocaproic acid (HICA), could be advantageous in maintaining lean body mass and reducing muscle soreness in elite athletes. Purpose: Therefore, the purpose of this study was to investigate the 6-week effects of a multi-ingredient performance supplement containing HICA, KIC, and BCAAs on body composition, strength, power and perceived soreness in resistance-trained athletes. Methods: Twenty resistance trained NCAA collegiate athletes were divided into one of 2 groups, MIPS + whey protein (n = 16; age, 19 ± 2; body fat, 14.68 ± 4.17; LBM, 68.16 ± 6.96; height, 185.58 ± 4.49 cm; weight, 86.93 ± 9.44 kg) or whey protein (n = 16; age, 19 ± 2; body fat, 14.93 ± 4.23; LBM, 66.95 ± 6.76; height, 185.90 ± 4.37 cm; weight, 83.81 ± 9.6 kg). Groups were randomized by their lean body mass, which was measured pre and post study via a Hologic dual-energy x-ray absorptiometry device (DXA) (Software version, encore 2013; Boston, MA, USA). Vertical jump was also assessed pre and post study for power via a Tendo Unit (Tendo Sports Machines, Slovak Republic). The supplement was administered post training sessions. An ANOVA with repeated-measures was used to analyze the effects of supplementation on dependent variables assuming group (CON and MIPS) and time (pre and post) as fixed factors. Results: There were no pre-to-post significant differences in lean body mass, fat mass or peak power between or within groups, however there was a trend towards significance for greater absolute change in desirable body composition index (e.g., DBCI = change in fat free mass [kg]−change in fat mass [kg] for the MIPS group (p < 0.06). There was a significant effect observed for increased Deadlift 1RM (CON: 2.6% and MIPS: 5.8%, p < 0.02). The MIPS group also demonstrated a trend towards increased recovery and decreased muscle soreness in conjunction with their progressive training protocol. Conclusions: These results suggest that a single serving (17 g) of a multi-ingredient performance supplement containing HICA does not appear to have a significant effect on lean body mass. However, it may be beneficial for faster recovery and thus greater strength gains in athletes. Based on this data, future research is necessary to determine if a larger dose of this supplement can have potential ergogenic effects in athletes.
The Effects of High-Intensity Interval Training and β-Hydroxy-β-Methylbutyric Free Acid Supplementation on the Electromyographic Fatigue Threshold (EMGFT)
A. Miramonti, J. Stout, E. Robinson, R. Wang, D. Fukuda, and J. Hoffman
University of Central Florida
Introduction: This study investigated the effects of high-intensity interval training (HIIT) and β-hydroxy-β-methylbutyric free acid (HMB-FA) on the onset of neuromuscular fatigue in healthy young men and women. Methods: Thirty-seven subjects (22 men and 15 women; mean ± SD, age = 22.8 ± 3.4 years) completed an incremental cycle ergometer test (GXT) to exhaustion. During the GXT, electromyography (EMG) signals from the right vastus lateralis were recorded to determine the power output at the onset of neuromuscular fatigue (EMGFT), and peak wattage was used to assign individual training loads. After baseline testing (PRE), subjects were randomly assigned to one of 3 groups: control (C, n = 9), training with placebo (P, n = 14), or training with supplementation (S, n = 14). Subjects assigned to P and S completed 12 HIIT sessions over 4 weeks, while subjects assigned to C were asked to maintain their normal diet and activity patterns. After 4 weeks, subjects returned for post testing (POST). The EMGFT values (W) were determined using a DMAX method. The EMG amplitude root mean square (μVrms) values were used to generate a third-order polynomial regression (3PR) representing the increase in μVrms versus time of the GXT. The onset of fatigue (TF) was defined as the x-value (time, s) of the point on the 3PR that measured the maximal perpendicular distance from the line between the first and last data points. TF was used to estimate EMGFT according to the equation: EMGFT = PO + a × (n/N), where PO is the power output of the stage in which TF occurred, a is the increment in power output between GXT stages (25W), n is the difference (s) between TF and the beginning of the stage during which TF occurred, and N is the duration of a stage (120 seconds). A 2-way repeated measures ANOVA was used to identify group × time interaction for EMGFT. If a significant interaction occurred, 1-way factorial ANOVAs were used. Fisher's least significant difference post hoc comparisons were performed between groups. If a significant main effect occurred, dependent samples t-tests with Bonferroni corrections (p = [0.05/3] = 0.017) were performed across time for each group. Results: The 2-way ANOVA resulted in a significant interaction (F = 6.69, p = 0.004). Follow-up analysis with 1-way ANOVA resulted in no difference among groups at PRE (F = 0.87, p = 0.43), however a significant difference was shown for POST values (F = 5.46, p = 0.009). Post-hoc analysis among POST values showed significant differences between S and both P (p = 0.034) and C (p = 0.003). No differences (p = 0.226) were noted between P and C. Paired samples t-tests detected significant changes following HIIT for S (p < 0.001) and P (p = 0.016), but no change in C (p = 0.473). Conclusions: Results of this study indicate that HIIT was effective in delaying the onset of fatigue, but supplementation with HMB-FA in conjunction with HIIT was more effective than HIIT alone. Practical Applications: An increase in EMGFT represents an increase in the maximal power output an individual can sustain without eliciting fatigue. Therefore, HIIT can be used to improve performance in both endurance activities as well as intermittent sports. In addition, HMB-FA supplementation is a simple method that can be used to maximize the benefits of HIIT.
The Effects of a Rapid Reintroduction of Carbohydrates Following a Ketogenic Diet
J. Partl,1 M. Sharp,2 R. Lowery,2 K. Shields,2 C. Hollmer,2 E. de Souza,1 J. Lane,1 D. Hayes Jr,1 J. Minevich,1 J. Rauch,1 J. Gray,1 J. Volek,3 D. D'Agostino,4 and J. Wilson1
1University of Tampa Human Performance Laboratory; 2University of Tampa Human Performance Lab; 3The Ohio State University; and 4University of South Florida
Introduction: Very low carbohydrate (70%) ketogenic diets (KD) diets have previously been shown to have favorable changes in body composition (increased lean mass and decreased fat mass) in resistance trained individuals . Not surprisingly, KD's are increasingly being used by bodybuilders and athletes to prepare for competitions. However, it is currently unknown how to properly reintroduce carbohydrates following a long period of keto adaptation. Purpose: In order to simulate a final contest preparation week, the purpose of this study was to examine the short-term effects various rates of carbohydrate reintroduction had on body composition in resistance trained individuals transitioning off a KD. Methods: Sixteen, college aged, resistance trained males participated in the study. Subjects were instructed to consume a ketogenic diet consisting of 5% carbohydrate, 25% protein, and 70% fat for 7 weeks. Additionally, subjects participated in a monitored, periodized resistance training program for the duration of the study. During week 8, subjects were divided into gradual (1 g·kg−1) or rapid (3 g·kg−1) carbohydrate reintroduction conditions. The other 8 subjects reintroduced carbohydrates to the diet at a rate of 3 g·kg−1. Body composition (Hologic Dual X-Ray Absorptiometry) was monitored every day until a “spillover” point was reached, defined as the point where there was no further changes in lean body mass in addition to increases in fat mass. Results: Throughout days 1 and 2, no subject in either group demonstrated an increase in fat content. On day 3, only 1 participant (12.5%) in the low-carb group demonstrated an increase in fat content, whereas 4 participants (i.e., 50%) reported a fat content increase in the high-carb group. In addition, throughout days 4 and 5, 4 participants (50%) reported increases in fat content in the low-carb group. On the other hand, in the high-carb group, 8 participants (100%) reported increases in the fat content. Both groups increased LBM when compared to keto-adapted period (p < 0.0001) by days 1 and 2 with no differences between conditions. However, compared to day 1, only the 1 g·kg−1 significantly increased LBM at days 2 and 3 (p < 0.0001 and p < 0.001), respectively. Conclusions: The primary finding of this study is that slow reintroduction of carbohydrate increases the ratio of DXA determined lean body mass to fat mass. Practical Applications: Slow carb reintroduction likely peaks glycogen storage in 2–3 days. If using a faster rate of reintroduction, there is a greater chance of gaining fat mass. Thus, faster reintroductions should be kept to shorter periods.
Reference: Rauch, JT, Silva, JE, Lowery, RP, McCleary, SA, Shields, KA, Ormes, JA, and Wilson, JM. The effects of ketogenic dieting on skeletal muscle and fat mass. J Int Soc Sports Nutr 11(Suppl 1): 40, 2014.
Effects of Pomegranate Extract on Anaerobic Exercise Performance and Resting Cardiovascular Responses
E. Roelofs,1 K. Hirsch,1 E. Trexler,1 M. Mock,1 and A. Smith-Ryan2
1University of North Carolina at Chapel Hill; and 2University of North Carolina
The popularity of pre-workout supplements has grown tremendously over the last decade, specifically those with ingredients thought to increase nitrate concentration such as pomegranate extract (PE). The ergogenic effect from PE has been linked to reduced vascular resistance, enhanced vasodilation, and increased blood flow. Purpose: To evaluate the effects of acute PE supplementation on anaerobic exercise, flow mediated dilation (FMD), heart rate (HR), blood pressure (BP), and oxygen saturation (SP02). Methods: Nineteen resistance-trained individuals (mean ± SD; Age: 22.1 ± 1.9 years; Height: 170.4 ± 12.4 cm; Weight: 68.7 ± 15.9 kg) participated in this crossover study. During visit 1, 1-repetition maximal (1RM) strength tests were performed on bench and leg press. For visits 2 and 3, one set at 80% of 1RM was completed for repetitions to fatigue (RTF) tests on bench and leg press. In a double-blind fashion, participants were randomized to either 1000 mg of PE or placebo (PL), and ingested in capsule form 30 minutes prior to the RTF test. Brachial artery FMD was assessed by ultrasound with vascular, pulse wave, and color flow settings to determine blood flow and vessel diameter. Heart rate, FMD, SPO2, and BP were assessed at baseline, 30 minutes post ingestion (30minPI), immediately post bench press (IPostBench), immediately post leg press (IPostLeg), and 30 minutes post exercise (30minPostEx). After a 7-day washout period, participants completed the RTF tests with the opposite treatment. Separate 2-way mixed factorial ANOVAs (treatment × time) were used to assess FMD, BP, HR, and SPO2, with Bonferroni post hoc comparisons. Change scores from PE to PL were calculated and 95% confidence intervals were placed around the mean change score. Results: There was no significant difference for the number of repetitions completed for bench press (p = 0.25) or leg press (p = 0.15) when consuming PE or PL. However, bench press (mean difference [MD] = 0.63 reps) and leg press (MD = 1.9 reps) repetitions were higher with the PE treatment. For vessel diameter, there was a significant interaction (p = 0.008) and main effect for time (p = 0.0001) and treatment (p = 0.03). Vessel diameter was significantly greater with the PE treatment for IPostBench (MD = 0.029 cm; p = 0.025), IPostLeg (MD = 0.042 cm; p = 0.001), and 30minPostEx (MD = 0.027 cm; p = 0.029). There was a significant main effect for time for blood flow (p < 0.001). Confidence intervals demonstrated blood flow IPostLeg was significantly higher with PE supplementation. There was a significant main time effect for HR (p < 0.0001), systolic BP (p = 0.001), and diastolic BP (p = 0.009). Conclusions: Acute supplementation of PE resulted in enhanced vessel diameter and blood flow, suggesting a possibility of enhanced exercise performance from increased delivery of substrates and nutrients to working skeletal muscle. Practical Applications: The acute timing and capsule form of PE may be advantageous to the athletic population due to ergogenic effects and compliance. Repetitions were increased after PE suggesting a potential for increasing training volume. Combining PE with other ergogenic aids, such as creatine, may be advantageous as a pre-workout supplement to further augment performance.
The 8 Week Effects of Low Carbohydrate Dieting vs. Very Low Carbohydrate Dieting With Refeed on Body Composition
M. Sharp,1 R. Lowery,1 K. Shields,1 C. Hollmer,1 J. Partl,2 D. Hayes Jr,2 J. Minevich,2 J. Rauch,2 J. Gray,2 E. de Souza,2 and J. Wilson2
1University of Tampa Human Performance Laboratory; and 2University of Tampa Human Performance Laboratory
Introduction: Improvements in body composition are often deemed as by-products of dieting strategies. One common strategy is found within the manipulation of carbohydrate intake. Our laboratory recently investigated the effects of a very low carbohydrate diet (VLCD) vs. a traditional western diet combined with resistance training (RT) and found that a VLCD augmented adaptations in body composition. However, the comparison of a VLCD and a very low carbohydrate diet with a refeed (VLCRD) on body composition has not been observed. Purpose: This study investigated the 8-week effects of 2 different very low carbohydrate dieting strategies on body composition in resistance-trained males. Methods: Sixteen resistance trained college aged males were randomized into 2 groups: VLCD and VLCRD. Participants of the VLCD group consumed a diet consisting of 5% CHO, 25% PRO, and 70% FAT daily for duration of the study whereas the VLCRD consumed the same macronutrient profile for the first 5 days of each week with a refeed (50% CHO, 25% PRO, 25% FAT) on the final 2 days of each week. All participants engaged in a 5 days per week training protocol that consisted of 3 days per week periodized RT with 2 days per week of high intensity interval training. Each participant was individually consulted by a dietician to be placed on a 500 kcal deficit from basal intake calculated by the Mifflin St. Jeor equation. Body composition was determined by a 10 hours fasted DXA assessment at week 0 and week 8. Repeated measures ANOVA was used to evaluate group, time and group by time interactions. When significance was detected a Tukey's Poc Hoc analysis was used to identify location of significance. Results: A significant group × time interaction for body composition following the experimental period was detected (p < 0.002). Post-hoc comparisons indicated that only the VLCRD group significantly decreased LBM (p < 0.003, −2.98%, [INCREMENT]: −2.08 kg). There were no significant changes in LBM for the VLCD group. However, only the VLCD group significantly reduced FM (p < 0.001; −19.6%; [INCREMENT]: −2.70 kg). There were no significant changes in FM for the VLCRD group. In addition, an absolute delta change analysis showed differences between absolute changes for decrease LBM in VLCRD group and decreased FM for VLCD group. Conclusions: Improvements in body composition appear to be enhanced in a strict VLCD when compared to a VLCRD when combined with resistance training after 8 weeks. Practical Applications: Resistance trained individuals seeking improvements in body composition should consume a VLCD (5% CHO, 25% PRO, 70% FAT) in conjunction with periodized resistance training while avoiding a consecutive 2 day refeed (50% CHO, 25% PRO, 25% FAT) of carbohydrate.
The Effects of Probiotic Supplementation on Markers of Muscle Damage and Performance Measures after an Intense Single-Leg Training Bout: A Pilot Study
K. Shields,1 M. Sharp,1 E. de Souza,2 R. Lowery,1 J. Partl,2 J. Minevich,2 C. Hollmer,1 J. Gray,2 J. Lane,2 J. Rauch,2 D. Hayes Jr,2 R. Jaeger,3 M. Purpura,3 and J. Wilson2
1University of Tampa Human Performance Laboratory; 2University of Tampa Human Performance Laboratory; and 3Increnovo LLC
Introduction: The probiotic Bacillus coagulans (GanedenBC30) has been shown to support healthy digestive and immune function. A recent pilot study in athletes indicated that co-ingestion of GanedenBC30 with a slow digesting protein during an 8-week full body workout increased performance in resistance trained athletes. We speculate that GanedenBC30's beneficial effects might be based on aiding muscle recovery through gut microbial modulation. Purpose: This pilot study investigated the impact of GanedenBC30 (GBI-30, 6086; Ganeden Biotech Inc., Maryfield Heights, OH, USA) supplementation on recovery, markers of muscle damage, and muscle performance following a muscle-damaging bout. Methods: Three recreationally active male subjects deprived of previous resistance-training experience were recruited to take part in a randomized, cross-over, double blind design. On day 0, subjects reported to the laboratory for baseline measurements (1RM Single Leg Leg-Press [1RM LP], Wingate Peak Power [WPP], Vertical Jump Peak Power [VJPP], Vastus Lateralis Thickness [MT], Creatine Kinase [CK] and Blood Urea Nitrogen [BUN]). Subjects administered either 20 g of casein (Control = CON) or 20 g of casein plus probiotic (500M BC30, = BC30) twice daily for the following 18 days. On day 14, subjects underwent an intense single-leg training bout designed to create muscle damage. At 24, 48, and 72 hours after the training bout Perceived Recovery (PR) and Perceived Soreness (PS) were measured via analogue scale. At 48 hours post testing, post measures (1RM LP, WPP, VJPP, MT, CK, and BUN) were taken. Subjects underwent 7 days of a wash-out and then crossed-over conditions. An ANOVA with repeated-measures was used to scrutinize the effects of different supplementation on selected-dependent variables (e.g., CK and Wingate power) assuming group (CON and BC30) and time (baseline and post) as fixed factors. Finally, within-group effect sizes (ES = pre-to-post changes/pre-test standard deviation) were calculated for the selected variables. The significance level was previously set at p ≤ 0.05. Results: No significant between group differences were detected at baseline for selected-variables (p > 0.05). The damaging exercise resulted in an increase in CK levels in the CON group (Pre: 157 U·L−1, Post: 1,606 U·L−1, ES: 13.6), however BC30 was able to blunt the increase in CK levels by 54% (Pre: 211 U·L−1, Post: 883 U·L−1, ES: 5.1). WPP decrease in the CON group by −16.1% (Pre: 694.5 Watts, Post: 582.6 Watts, Delta: −111.9 Watts), whereas WPP increased in the BC30 group by 6.9% (Pre: 599.5 Watts, Post: 640.9 Watts, Delta: +41.4 Watts). No significant differences (p > 0.05) were observed between groups in any of the measures due to the small sample size. Conclusions: BC30 administration seems to have a beneficial effect on muscle damage, consequently leading to improved performance thereby providing a strong rationale for conducting a larger study to investigate the effects of this probiotic on muscle recovery and performance. Practical Applications: While further research is needed, large effect size differences between groups indicate that athletes benefit from GanedenBC30 supplementation.
The Influence of Hydration Status on Changes in Body Mass During Creatine Supplementation
E. Sobolewski,1 E. Ryan,2 C. Kleinberg,3 A. Tweedell,2 B. Bokoski,4 and A. Smith-Ryan5
1Texas Tech University; 2University of North Carolina-Chapel Hill; 3University of North Carolina-Chapel Hill; 4Bare Nutrition; and 5University of North Carolina
It is commonly reported and speculated that Creatine (Cr) supplementation causes increases in body mass. Creatine's osmotic properties are believed to increase intracellular water (ICW), resulting in greater water retention and subsequent increases in body mass. Purpose: The purpose of this study was to examine the influence of hydration status on the changes in body mass and fluid distribution during Cr supplementation. Methods: Fifty subjects (age = 20 ± 2 years), where assigned to a Cr (n = 25) or a placebo group (n = 25). Participants supplemented 4 times daily for 5 days with 5 g Cr monohydrate +20 gdextrose (Cr) or 20 g dextrose (PL). Testing was conducted prior to supplementation and during the loading phase on days 2, 4, and 6. Bioelectrical Impedance Spectroscopy was used to determine total body water (TBW), extracellular water (ECW) and ICW. Hydration status was determined through urine specific gravity as determined by a refractometer at baseline prior to supplementation. A mixed factorial ANOVA and ANCOVA controlling for hydration status was used to examine body mass, TBW, ECW, and ICW. Follow up bonferonni corrected comparisons were used when appropriate. Results: For body mass alone there was no interaction effect (F = 0.88, p = 0.08), no main effect for group (F = 4.80, p = 0.91), but a mass did increase over the 6 days for both groups (F = 7.34, p < 0.01). When accounting for hydration status there was an interaction effect for body mass (F = 3.06, p = 0.03). The placebo group weighed more at baseline but after 3 full days (day 4) of supplementation, both groups were similar in body mass for the remainder of the loading period as a result of the ∼0.6 kg (p ≤ 0.05) increase in body mass for the Cr group. There was no interaction or main effects for TBW, ECW or ICW (p > 0.05), however when controlling for hydration status there was only a significant difference between groups for ECW (F = 4.38, p = 0.04) with the PL group being higher than the Cr group at all-time points. Conclusions: The results of this study indicate that hydration status may play a role in the mass gain associated with Cr supplementation with those being less hydrated not experiencing the same amount of mass changes as those who are hydrated. If the osmotic conditions outside the cell are high in solutes then an increase in cellular Cr levels may not pull water into the cell thus not cause an increase in water content as seen with this study. Practical Applications: It has been suggested to coaches and players to drink more water with Cr supplementation but this study found that the increase in mass seen with Cr use maybe due to increased water/fluid supplementation rather than Cr alone. It is recommended that Cr users maintain healthy hydration levels and not “over” consume water as excess water leads to mass gain not Cr.
Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading
E. Trexler,1 E. Roelofs,1 K. Hirsch,1 M. Mock,1 and A. Smith-Ryan2
1University of North Carolina at Chapel Hill; and 2University of North Carolina
Scarce research has indicated that caffeine anhydrous (CAF) blunts the ergogenic effect of creatine monohydrate (CRE) loading. These findings have been questioned, as early studies demonstrated ergogenic effects from CRE mixed into caffeinated coffee (COF). Purpose: To determine if chronic COF or CAF intake modulates the effects of CRE loading on strength and sprint performance. Methods: Resistance-trained males (n = 54; Mean ± SD; Age = 20.1 ± 2.1 years; Height = 177.3 ± 5.6 cm; Weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of one-repetition maximum and repetitions to fatigue (RTF) for bench press (BP) and leg press (LP), followed by a repeated sprint test consisting of 5, 10-second sprints on a cycle ergometer loaded with 9.5% of bodyweight. Peak power (PP) and total work (TW) were recorded for each sprint, along with average PP and TW for all 5 sprints. Subjects were randomly assigned to supplement with CRE (5 g, 4 times per day), CRE + CAF (CRE +300 mg·d−1 of CAF), CRE + COF (CRE + a caffeine-matched dose (8.9 g) of instant COF), or placebo (PLA) for 5 days. On day 6, participants completed post-testing. Serum levels of creatinine (CRN) were measured pre and post supplementation. Results: A main effect for time was observed for all strength measures (p < 0.001), with no significant interactions. 95% confidence intervals (CIs) revealed significant improvements by all groups in all strength outcomes, except for a non-significant improvement in BP RTF for CRE + COF (+0.2 ± 1.5 reps; p > 0.05). No significant interaction or main effects were observed for PP. For TW, a significant time × sprint interaction resulted (p = 0.02), with a main effect for sprint (p < 0.001). While not statistically significant, average TW dropped in PLA (ΔMean ± SEM; −110.7 ± 116.1 Joules [J]), but not in CRE + COF (+17.6 ± 135.7 J), CRE + CAF (+22.2 ± 112.5 J), or CRE (+31.6 ± 104.2 J). A significant time × treatment interaction was observed for serum CRN values (p = 0.04). 95% CIs showed significant increases in serum CRN for all groups except PLA. Four subjects reported mild gastrointestinal (GI) discomfort in CRE + CAF, with none reported in other groups. Conclusions: CRE did not improve performance to a greater extent than PLA. Results do not suggest that performance outcomes from CRE loading were influenced by the addition of CAF or COF, but that the combination of CRE + CAF may cause mild GI discomfort. In healthy, resistance-trained males, elevated serum CRN may be observed with CRE loading, and does not necessarily indicate kidney dysfunction. Practical Applications: Athletes interested in increasing strength and sprint performance may require longer duration CRE supplementation, in conjunction with progressive training, to see appreciable improvements in the variables measured. Those consuming CRE may avoid CAF, or potentially manipulate the timing of CAF ingestion, to avoid GI discomfort, but this may not be necessary for COF. Athletes should be mindful of potential GI symptoms when using supplements with high doses of CRE + CAF prior to training or competition.
Consuming a Purported ATP-Enhancing Substance With Caffeine Increases Lower Body Strength, Power and Hypertrophy vs. Placebo in Trained Men
R. Vogel,1 J. Joy,2 P. Falcone,1 M. Mosman,1 M. Kim,1 and J. Moon1
1MusclePharm; and 2Concordia University Chicago/MusclePharm
Various ergogenic substances aim to improve measures of strength, power and muscle hypertrophy in athletic populations. A novel ingredient, consisting of ancient peat and apple extracts, may enhance cellular ATP production and thereby improve these measures. Purpose: To examine the effects on performance and muscle hypertrophy of a purported ATP-enhancing substance combined with extended release caffeine, caffeine anhydrous, and B-vitamins (AES) versus placebo (PLA) after 12 weeks periodized resistance training. Methods: Twenty-one resistance-trained males (mean ± SD; 27.2 ± 5.6 years; 173.5 ± 5.7 cm; 82.8 ± 12.0 kg) participated in this randomized, double-blind, placebo controlled study. Subjects consumed 1 serving (1.5 ml) daily of either AES (n = 10), containing 150 mg of a proprietary blend of ancient peat and apple extracts, 180 mg of a blend of extended release caffeine and caffeine anhydrous, and 38 mg B-vitamins, or visually identical PLA (n = 11) 45 minutes before training on workout days and at a similar time of day on non-workout days. Subjects participated in supervised daily undulating periodized resistance training 3 days per week for 8 weeks followed by 2 weeks each of overreach and taper phases. Measures of upper and lower body power (bench press power, vertical jump) and maximal strength (bench press, deadlift, back squat 1RM), as well as ultrasound-determined cross-sectional area (CSA) of the rectus femoris and muscle thickness (MT) of the vastus lateralis and vastus intermedius were collected at weeks 0, 4, 8, 10, and 12. A repeated measures ANOVA was used to determine all group, time, and group by time interactions. Results: Significant group by time interactions (p ≤ 0.05) were present for squat 1RM (PLA: +15.8 kg; AES: +28.0 kg), vertical jump peak power (PLA: +192.9 W; AES +401.9 W), and peak velocity (PLA: +0.15 m·s−1; AES: +0.45 m·s−1) from pre to post supplementation. Significant group by time effects (p ≤ 0.05) were observed for total strength (squat 1RM + bench 1RM + deadlift 1RM), in which there were no effects from pre to post, yet AES increased to a greater extent than PLA from weeks 4–10 (PLA: +2.1 kg, AES: +22.3 kg), weeks 4–12 (PLA: +11.0 kg, AES: +37.3 kg), and weeks 8–12 (PLA: +3.4 kg, AES: +18.3 kg). Significant group by time interactions (p ≤ 0.05) were observed for CSA (PLA: −0.08 cm2; AES: +1.07 cm2) and MT (PLA: +0.05 cm; AES: +0.49 cm) from pre to post supplementation. No significant group by time interactions were observed for bench press power or 1RM (p > 0.05). Conclusions: The present findings suggest that AES may improve lower body strength and power adaptations and increase muscle hypertrophy within the context of a periodized 12 weeks resistance training program. Practical Applications: Athletes and recreationally active populations may benefit from supplementation with the product used in this investigation, particularly if they seek to augment increases in lower body strength, power, and hypertrophy while participating in a structured resistance training program.
Differing Rates of Decline in Velocity Between the Bench Press And Back Squat Over Multiple Sets
A. Anzalone,1 A. Jagim,2 M. Jones,3 and J. Oliver1
1Texas Christian University; 2University of Wisconsin-La Crosse; and 3George Mason University
In order to maintain velocity during a prescribed set, the appropriate repetition number should be chosen based upon when a substantial decline in velocity is observed. Differences have been reported between bench press and back squat in the time-course of decrements in movement velocity when repetitions are performed to failure; however, whether these differences are observed over the course of multiple sets is unknown. Purpose: Therefore, the purpose of this study was to examine the pattern of velocity decline over successive sets in the bench press and back squat. Methods: Twelve (n = 12) Division III American football athletes (18.8 ± 1.2 years; 180 ± 12 cm; 89.3 ± 11 kg) had their body composition assessed ([hydrostatic] 13.6 ± 4.9% body fat) and 5 repetition maximum (5RM) determined in the back squat and bench press exercise on a smith machine. After a minimum of 72 hours, and refraining from strenuous exercise >48 hours, subjects returned to perform 5 sets of 5 repetitions (5 × 5) at a load corresponding to 85% 5RM with 2 minutes separating each set. The back squat preceded the bench press with 10 minutes recovery in between lifts. Average velocity (AV) and peak velocity (PV) were measured by a linear position transducer attached to the inside sleeve of the barbell. A repeated measures ANOVA was used to examine the time-course of decrements in velocity. Significance was set at p ≤ 0.05. Results: A significant SET × REP interaction (p = 0.024) was observed in AV for back squat, in which post hoc analysis demonstrated a similar pattern of decline across all sets. Both AV and PV were maintained throughout all sets in the back squat (p = 0.422 and p = 0.114, respectively) and bench press exercises (p = 0.104 and p = 0.557, respectively). When collapsed across the 5 sets, the decrease in PV from repetition 1 started at repetition 4 (p = 0.003) in the back squat and repetition 3 (p = 0.030) in the bench press. In contrast, when collapsed across all sets, the decrease in AV from repetition 1 started at repetition 3 (p < 0.001) in the back squat and repetition 4 (p = 0.024) in the bench press. Conclusions: These data suggest that at the specified intensity (85% 5RM), the athletes in this study were able to maintain velocity over multiple sets. Further, a similar pattern of decline in velocity was observed over successive repetitions in a given set in the bench press and back squat. However, PV decreased at a slightly greater rate in the bench press exercise, while AV decreased at a slightly greater rate in the back squat. Practical Applications: When attempting to maximize velocity in a resistance training program, strength and conditioning professionals should determine the rate of decline in velocity to ensure velocity is maintained over the course of multiple repetitions. In addition, performing more than 3 repetitions may elicit a decline in velocity in both the back squat and bench press at an intensity of 85% 5RM.
Block vs. Traditional Periodized Strength Training Programs in Women
S. Bartolomei,1 J. Stout,2 D. Fukuda,2 J. Hoffman,2 and F. Merni3
1Department of Biomedical and Neuromotor Sciences, University of Bologna; 2University of Central Florida; and 3Department of Biomedical and Neuromot Sciences, University of Bologna
Traditional and Block periodized strength training programs have been used by male and female athletes over the past several decades for many sports. Purpose: The aims of this study were to compare the effects of block periodization (BP) and traditional periodization (TP) resistance training on maximal strength and hypertrophy in recreationally strength trained women. Methods: Seventeen recreationally trained women were randomly assigned to either a BP group (n = 9; age = 24.7 ± 4.2 years; body mass = 62.1 ± 5.3 kg; height = 166.4 ± 6.0 cm) or TP group (n = 8; age = 23.2 ± 2.2 years; body mass = 59.8 ± 11.9 kg; height = 160.1 ± 4.1 cm). Participants of both groups trained 3 days a week for 10 weeks. BP and TP programs were equated in total training volume and used the same exercises. The difference between the 2 programs was in the distribution of the training volume within each training phase. Anthropometric measures and strength tests were performed before (PRE) and after 10 weeks (POST) of training. Arms and thigh muscle area were estimated by the limbs circumferences and skinfolds using apposite equations. Results: The results revealed that both BP and TP groups made significant increases in strength and power (+27.7% and +8.8% for TP group and +15.2% and +4.1% for BP group in squat 1RM and in CMJ respectively) but, improvements in lower body strength were significantly (p ≤ 0.05) greater in the TP compared to BP. Both groups significantly increased arm muscle hypertrophy (p < 0.01), whereas improvements in thigh muscle size were significant in the TP group only (+5.8%, p = 0.01). Conclusions: Results of this study indicate that the traditional periodization model is more effective than the block periodization model for increasing maximal strength and muscle size in the lower body in women. Practical Applications: Strength and conditioning professionals may realize greater success in strength and hypertrophy gains using the traditional model of resistance training, when working with recreationally trained women.
The Electromyographical Comparison of Superficial Musculature During Abdominal Exercises
A. Hallmark,1 R. Snarr,1 and M. Esco2
1University of Alabama; and 2The University of Alabama
Core training is an important aspect for strength and conditioning, rehabilitation, and clinical outpatient settings. Core musculature strength and endurance is important for optimal balance, stability, and lower back injury prevention. Long-term core training has also been associated with increases in athletic performance and power development. Purpose: The purpose of this investigation was to compare the electromyographical differences between the rectus abdominis (RA), external oblique (EO), lumbo-sacral erector spinae (LSES), and rectus femoris (RF) during abdominal based movements in resistance-trained individuals. Methods: Sixteen apparently healthy men (n = 8; age, 25.8 ± 6.4 years; height, 177.9 ± 9.3 cm; weight, 82.4 ± 6.9 kg) and women (n = 8; age, 23.5 ± 1.2 years; height, 164.7 ± 7.7 cm; weight, 62.2 ± 8.1 kg) volunteered to participate in this study. Surface electrodes were placed on the RA, EO, LSES and RF. Subjects then performed 4 abdominal movements as follows: crunch (C), pike (P), V-up, and towel pike (TP). Three repetitions per movement were performed at rate of 2 seconds per concentric and eccentric phases. Results: Results are shown in Table 1. For the RA, the C demonstrated significantly higher activity than the P and significantly lower activity than the V-up. In terms of the EO, the P elicited a significantly lower %MVC value than the TP and V-up. For the RF, the C demonstrated the lowest activation, while the TP had the greatest activity than all other exercises. Lastly, the LSES demonstrated no significant differences between any of the exercises. All significant differences had a p < 0.001, unless otherwise stated. Conclusions: Exercises that appeared to have the least range of motion and body weight resistance such as the C and P demonstrated lower activity in the RA and RF. Whereas, exercises that appeared to have a greater range of motion and body weight resistance, resulted in higher activation in the EO due to greater stability demands as shown in the TP and V-up. The TP provided the greatest activation of the RA, EO, and RF, possibly due to use of frictional forces (i.e., between the towel and floor) to complete the movement, thereby adding a greater resistance component. Practical Applications: These findings provide a deeper look into traditional abdominal based movements and can provide a means of progression for athletic conditioning and rehabilitation programs. This information may provide practitioners with a more practical means of determining proper exercise selection based upon the skill level and strength of the client or athlete.
Methodological Considerations for an Isometric Bench Press Protocol
R. Harmon, K. Malyszek, D. Dunnick, A. Galpin, J. Coburn, and L. Brown
California State University, Fullerton
The barbell bench press is frequently used in resistance training as a measure of maximum upper body strength. However, isometric testing may provide a less fatiguing and technique based alternative to 1RM testing. Purpose: To examine dynamic bench press 1RM, isometric bench press (MVIC), and differences in anthropometrics within them. Methods: Twenty resistance trained men (age = 24.70 ± 2.43 years; height = 179.23 ± 6.42 cm; mass = 90.92 ± 13.19 kg; arm length = 61.5 ± 3.34 cm; bench press 1RM = 123.30 ± 17.34 kg; MVIC = 130.03 ± 18.74 kg) participated. Participants completed both a 1RM and MVIC trial. Grip width was recorded and replicated for both conditions. For the 1RM test, subjects performed a warm-up consisting of 6 repetitions at 50% of their estimated 1RM, 3 repetitions at 85%, then began maximum attempts starting at 90% of their estimated 1RM. Subjects were allowed 5 attempts to reach their actual 1RM. For the MVIC, a power rack was positioned over a force plate with the barbell fixed in the rack at a height equal to 50% of subject's arm length. A flat bench was placed on the force plate, with only the upper body supported on the bench. Subjects were then instructed to push against the barbell with maximum force. Results: Subjects' MVIC was 106.62 ± 16.80% of their 1RM bench press. However, correlation of MVIC with 1RM revealed an r value of only 0.518. Correlation of height and arm length revealed an r value of 0.735. Body mass supported by the bench on the force plate was 39.96 ± 2.82% of total mass. Correlation of 1RM and MVIC may be affected by the location of the sticking point. Therefore, the relationship may vary when MVIC is tested at different joint angles. Conclusions: Based on these results, it can be concluded that bench press MVIC is moderately correlated with 1RM. However, as bench press styles and anthropometrics vary, performing an MVIC at 50% of arm length may impact the ability to generate maximum force given the length/tension relationship of muscle. Practical Applications: Based on individual variance, the correlation between 1RM and MVIC bench press may be altered if MVIC trials are performed at a self-selected bar height. Future studies should investigate MVIC trials at varying arm lengths of 25, 50, 75%, and a self-selected height.
The Effects of Supplementation With p-Synephrine and Caffeine on Lipolytic and Cardiovascular Responses During Resistance Exercise
N. Ratamess,1 J. Bush,1 J. Kang,1 W. Kraemer,2 S. Stohs,3 V. Nocera,1 M. Leise,1 K. Diamond,1 L. Pigott,1 J. Pacifico,1 C. Noonan,1 and A. Faigenbaum1
1The College of New Jersey; 2The Ohio State University; and 3Creighton University
Purpose: To examine the effects of supplementation with p-synephrine (alone and in combination with caffeine) chews on lipolytic and cardiovascular responses during resistance exercise (RE). Methods: Twelve healthy, college-aged men performed a control (CT) RE protocol consisting of 6 sets of squats for up to 10 repetitions per set using 80% of their one repetition-maximum (1RM) with 2 minutes of rest in between sets. Each subject was randomly assigned (in double-blind manner) to a treatment sequence consisting of use of 3 supplements in identical chew form: p-synephrine (AZ; 100 mg), p-synephrine + caffeine (AZCF; 100 mg of p-synephrine plus 100 mg of caffeine), or a placebo (P). For each supplement treatment (separated by 1 week), subjects reported to the lab in a fasted state at a standard time, consumed a supplement, sat quietly for 45 minutes, performed the RE protocol, and sat quietly for 30 minutes post exercise. Blood samples (for measurement of serum glycerol and plasma glucose) were taken at rest (T1), after sitting quietly for 45 minutes (T2), immediately following RE (T3), 15 (T4), and 30 (T5) min post exercise. Heart rate (HR) was assessed via a Polar HR monitor at rest (BL), every 5 minutes during the 45-minute quiet sit, following each set of RE and rest interval, and every 5 minutes during the 30-min post-exercise period. A 2-way analysis of variance with repeated measures was used to analyze all within-subject data. Results: Serumglycerol was significantly elevated at T2 only in AZ and AZCF, and T3 to T5 during all treatments. Analysis of area under the curve (AUC) between T1 and T3 revealed an approaching trend (p = 0.13) for higher values in AZCF and AZ compared to CT and P. Plasma glucose was significantly elevated at T2 (in P, AZ, and AZCF only), T3, T4, and T5 compared to T1. Plasma glucose and AUC values seen in AZCF were significantly higher than CT, P, and AZ. Mean HR during quiet sitting did not differ between treatments. Mean HR during RE was significantly higher in AZCF compared to CT by 3.5%; trends were seen in comparison to P by 2.4% (p = 0.09) and AZ by 2.8% (p = 0.06). Mean post-exercise HR tended (p = 0.11) to be higher in AZCF compared to CT and P by 4.5 and 4.2%, respectively, and AZ did not differ from CT and P. Conclusions: Supplementation with p-synephrine alone and in combination with caffeine increased glycerol (a marker of lipolysis) at rest and during RE. p-synephrine consumed by itself did not increase cardiovascular demand at rest or during RE. However, the addition of caffeine to AZ increased HR during and after RE. No significant side effects were observed. Practical Applications: Supplemental chews containing 100 mg of p-synephrine augment lipolysis but do not increase the HR response at rest or during RE unless caffeine is added.
Muscle Activation, Muscle Swelling, and Exercise Volume During Three Sets to Failure at 80% vs. 30% 1RM Resistance Exercise
N. Jenkins,1 T. Housh,1 H. Bergstrom,2 K. Cochrane,1 E. Hill,1 C. Smith,1 N. Yeo,1 J. Miller,1 and J. Cramer1
1University of Nebraska-Lincoln; and 2University of Kentucky
Resistance training at 30% of one repetition maximum (1RM) elicits similar muscle hypertrophy as training at 80% 1RM when performed to failure (Mitchell et al. J Appl Physiol 113: 71–77, 2012). However, it is unclear how muscle activation influences these adaptations. Purpose: Therefore, the purpose of this study was to investigate electromyographic amplitude (EMG AMP), EMG mean power frequency (MPF), muscle cross sectional area (mCSA), exercise volume (VOL), total work and muscle activation (iEMG), and time under concentric tension (TUCT) during 3 sets to failure at 80% vs. 30% 1RM leg extension resistance exercise in men and women. Methods: Eleven men (mean ± SD; age = 21.5 ± 2.7 years; resistance training per·week = 6.6 ± 3.7 hours) and 11 women (age = 22.3 ± 3.6 years; resistance training·per week = 3.7 ± 3.3 hours) completed 1RM testing, followed by 2 experimental sessions during which they completed 3 sets to failure of leg extension resistance exercise at 80 or 30% 1RM. EMG signals were recorded from the 3 superficial quadriceps femoris muscles of the dominant thigh. An electrogoniometer was placed across the knee joint to measure joint angle (°). Exercises were performed on a plate-loaded leg extension device that was custom fitted with a load cell. Force, EMG AMP (μV·s−1), and EMG MPF (Hz) values were calculated from signal epochs corresponding to the 60° range of motion occurring between 100° and 160° of leg extension during the concentric portion of each repetition (rep) based on the electrogoniometer signal. The EMG AMP and MPF values from the initial, middle, and last rep of each set were normalized to a maximal voluntary isometric contraction (MVIC) and used for analyses. Panoramic ultrasound imaging was used to assess mCSA of the rectus femoris and vastus lateralis immediately pre- and post-exercise. Exercise volume, total work, iEMG, and TUCT were also quantified. Results: The mean ± SD for the numbers of reps completed during sets 1, 2, and 3 were 8.9 ± 2.7, 6.7 ± 1.9, and 6.2 ± 1.7 at 80% 1RM, and 45.6 ± 14.3, 26.8 ± 8.3, and 22.2 ± 8.6 at 30% 1RM, respectively. EMG AMP increased across reps and sets at 80 and 30% 1RM, but was consistently greater for 80 than 30% 1RM. EMG MPF decreased across reps at 80 and 30% 1RM, but decreased to a greater extent and was lower for the last reps at 30 than 80% 1RM (71.6% vs. 78.1% MVIC). mCSA increased more from pre-to post-exercise for 30% (20.2 cm2–24.1 cm2) than 80% 1RM (20.3 cm2–22.8 cm2). VOL, total work, iEMG and TUCT were greater for 30 than 80% 1RM. Conclusions: EMG AMP remained greater at 80 than 30% 1RM across all repetitions and during all sets, despite 74 and 147% increases in EMG AMP during the sets at 80 and 30% 1RM, respectively. VOL, total work, iEMG, and TUCT were 18–202% greater, and the decreases in EMG MPF were more pronounced at 30% 1RM. Furthermore, the increases in mCSA (i.e., muscle swelling) from pre-to post-exercise were greater at 30 than 80% 1RM. Practical Applications: Muscle activation was greater during resistance exercise at 80 than 30% 1RM. Therefore, muscle activation may not be responsible for the similar hypertrophy observed after 30 vs. 80% 1RM training to failure. Exercise volume, metabolic byproduct accumulation, and muscle swelling, however, may be contributing factors. Additional studies are needed to investigate the acute and chronic neuromuscular responses to high-versus low-load resistance training.
The Effects of an Eight Week Ketogenic Diet vs. a Cyclical Ketogenic Diet on Performance and Testosterone in a Resistance Training Program
J. Lane,1 M. Sharp,2 R. Lowery,2 K. Shields,2 C. Hollmer,2 J. Partl,1 D. Hayes Jr,1 J. Minevich,1 J. Rauch,1 J. Gray,1 E. de Souza,1 J. Volek,3 D. D'Agostino,4 and J. Wilson1
1University of Tampa Human Performance Laboratory; 2University of Tampa Human Performance Laboratory; 3The Ohio State University; and 4University of South Florida
Introduction: Our lab recently examined the effects of the ketogenic diet (KD) compared to a western diet regarding strength related performance; additionally, free and total testosterone was evaluated. Individuals on the KD saw similar adaptations in strength and similar changes testosterone. Comparisons of the KD against a cyclic (CKD) in strength, endurance, and testosterone have not been previously demonstrated in literature. Purpose: Therefore the purpose of this study was to investigate the effects of the KD versus a CKD on performance and testosterone in resistance-trained males. Methods: Sixteen resistance trained males participated in the study (mean ± SD; age: 23.5 ± 3.3; weight: 187.6 ± 32.6). Participants on the KD consumed 5% carbohydrate, 25% protein, and 70% fat for 8 weeks. The CKD group applied the same macronutrient ratio to their diet Monday through Friday, while altering the ratio on weekends (50% carbohydrate, 25% protein, 25% fat). A periodized resistance training program was strictly followed 3 days per week throughout the duration of the study with high intensity interval training implemented on intermittent days 2 times per week by all participants. Participants were placed on a 500 kcal deficit derived from basal metabolic rate determined by the Mifflin St. Jeor equation. One repetition maximum (1RM) strength was assessed on deadlift, bench press, and leg press at baseline with a repeat assessment performed Week 8. Strength endurance was assessed on the leg press at baseline and re-assessed at Week 8. Free and total testosterone was evaluated at baseline and at Week 8. An ANOVA with repeated-measures was used to scrutinize the effects of KD and CKD on dependent variables assuming group (KD and CKD) and time (pre and post) as fixed factors. The significance level was set at p ≤ 0.05. Results: There were no differences between groups in the performance tests or testosterone levels detected at baseline (p > 0.05). A time effect was observed for bench press and deadlift 1RM (p < 0.01). There was a trend towards a group by time interaction (p = 0.07) which favored an increase in the leg press 1RM in the KD group. There were no significant differences for leg press strength endurance in both groups. For free testosterone, there were no group or group × time interactions (p > 0.05). For total testosterone, there was a group × time interaction following the diet treatment (p < 0.02). The pairwise comparisons revealed that only the cyclic group decreased in total testosterone (10.3%, p < 0.02). Conclusions: In regards to performance, a strict KD seems to augment positive strength related adaptations when compared to a CKD. These responses may be explained by sustained total testosterone levels seen in the KD group compared to reductions in total testosterone as a result of the fluctuations in macronutrient intake. Practical Applications: Individuals attempting to optimize adaptations in strength performance while maintaining testosterone levels should perform a KD compared to a CKD.
Prediction of Dynamic Bench Press 1RM via Isometric Bench Press Force
K. Malyszek, D. Dunnick, R. Harmon, A. Galpin, J. Coburn, and L. Brown
California State University, Fullerton
The barbell bench press is a commonly used measurement of upper-body strength. However, maximum bench press testing is difficult and skill based. Purpose: The purpose of this study was to develop a regression equation to predict dynamic bench press (1RM) via isometric bench press force (MVIC). Methods: Fourteen resistance trained men (age = 24.14 ± 2.25 years; height = 179.09 ± 5.87 cm; mass = 88.79 ± 10.08 kg; bench press 1 RM = 126.72 ± 11.46 kg; relative RM = 1.43 ± 0.12) participated. They completed both a 1RM and a MVIC. Grip width was recorded and replicated for both conditions. For the MVIC, a power rack was positioned over a force plate with the barbell fixed in the rack at a height equal to 50% of the subject's arm length. A flat bench was placed on the force plate, and the subject was instructed to push against the barbell with maximum force. Results: Regression analysis resulted in R = 0.734 between 1RM and MVIC. The equation for predicting 1RM from MVIC was y = 0.379x + 77.088, where x is maximal isometric force (R 2 = 0.538, SEE = 8.10). Based on an R 2 value of 0.538, approximately 54% of 1RM is explained by MVIC, leaving approximately 46% unexplained. The unexplained variance could be attributed to differences in anthropometrics, as height, mass, and mass distribution varied across subjects. Additionally, differences in arm length could have contributed as arm length and height are highly correlated. As MVIC may be affected by the location of the sticking point in the range of motion, the correlation between 1RM and MVIC may vary when testing at different joint angles. Conclusions: Based on these results, 1RM and MVIC are moderately to highly correlated. Therefore, bench press 1RM can be moderately predicted from MVIC using the present equation within ±8.10 kg. Practical Applications: As isometric testing entails less skill and fatigue than maximal dynamic efforts, isometric bench press may be a viable alternative to dynamic 1RM testing.
Correlations Between Body Composition and Muscular Strength Support a Mixed Model Approach to Resistance Training
J. Mata,1 M. Jones,2 A. Jagim,3 P. Carr,2 J. Martin,2 and J. Oliver4
1Texas Christian University; 2George Mason University; 3University of Wisconsin-La Crosse; and 4Texas Christian University
To maximize muscular power, a mixed model approach to resistance training produces superior results to a one-dimensional approach. We recently reported significantly greater power in men compared to women in the conventional deadlift exercise. Further, when normalized to fat free mass (FFM), women produced significantly higher velocities across all loads suggesting the implementation of differing strategies in the form of a mixed model training approach based upon sex. However, whether those differences are attributed to the greater strength and lean mass observed in men is unknown. Purpose: Therefore, we sought to examine the relationship amongst FFM, strength, velocity, and power in the conventional deadlift exercise across a range of loads. Methods: Eighteen strength training athletes (women: n = 9, mean ± SEM, 29 ± 2 years, 162.3 ± 1.8 cm, 62 ± 2.4 kg; men: n = 9, 29 ± 3 years, 175.6 ± 1.8 cm, 85.5 ± 1.4 kg) had their body composition assessed [(BodPod) women: 23.3 ± 3.2% body fat (BF), men: 14.8 ± 2.4% BF] and one-repetition maximum (1RM) determined in the conventional deadlift followed by 3 testing sessions separated by 7 days each. At each session, subjects completed a supervised warm-up followed by 3 conventional deadlift repetitions separated by 2-minutesrest at one of 3 randomly assigned workloads (30, 60, 90%). Average and peak velocity, average and peak power were measured by a Tendo Analyzer (Tendo Sports Machines, Slovak Republic), attached inside the sleeve of the barbell. Bivariate (Pearson) correlations were computed to examine relationships amongst body composition, strength, power, and velocity. Results: A strong correlation was observed between FFM and 1RM (Table 1). Both FFM and 1RM were strongly correlated with average and peak velocity across all loads. FFM and 1RM were only moderately correlated with average and peak velocity. Interestingly, these relationships were positive at 30% 1RM, but negative at 90% 1RM. Conclusions: These data suggest that the greater power across loads observed in men is primarily the result of their larger muscle mass, which contributes to the greater strength observed as well. Practical Applications: When employing a mixed model approach to resistance training, strength and conditioning coaches should focus on those areas of weakness. Thus, greater proportion of time should be spent on strength training (high load-low velocity) in women athletes, whereas, velocity (low load-high velocity) should be a focus in strategies used for men.
Does a Rigorous Multi-Shift Work Schedule Impact Balance, Response Time, and Strength-Related Performances in Female Healthcare Workers?
B. Thompson,1 V. Banuelas,1 C. Akalonu,1 A. Moore,2 and M. Stock1
1Texas Tech University; and 2Texas Tech University-Health Sciences Center
The healthcare industry is the fastest growing sector of the workforce, and is characterized by high work demands. Accordingly, nurses sustain among the highest injury rates of any profession, possibly attributed to demanding work schedules which commonly consist of 12-hour shifts performed in a cumulative pattern. It is possible fatigue may accumulate from demanding nursing work and contribute to enhanced injury risks; however, the effects of multi-shift work periods have not been evaluated on functional performance abilities. Purpose: To investigate the effects of a demanding multi-shift work period on performance capacities in female healthcare workers. Methods: Eighteen (mean ± SD, range: age = 30.2 ± 7.7, 19–45 years) fulltime female nurses volunteered for this investigation. Nurses included RN's, LVN's and nurses' aides, currently working 12-hour shifts. Following a separate visit to the laboratory for familiarization on all performance tests, nurses reported to the laboratory 2 more times for pre- and post-testing, which were separated by a work period consisting of three, 12-hour shifts in a 4-days time period (working 36 hours in a 96 hours period). Pre- and post-testing outcome measures included static balance, reaction time (RT) and maximal and explosive grip strength. Nurses performed a 5-minute computer-based psychomotor vigilance task (PVT) to assess vigilance-related RT, in addition to simple and choice RT tasks. Double- and single-leg static balance was assessed for 30-second on a balance device, which computed an overall stability score based on postural sway. Participants also performed 2–3 maximal voluntary contractions on an electronic hand grip dynamometer. Dynamometer signals were sampled at 1,000 Hz and subsequently low-pass filtered at a 50 Hz cutoff. MVC's were used to calculate peak force (PF; N) and peak rate of force development (RFDpeak; N·s−1), as the highest 500 milliseconds epoch and maximal slope of the ascending portion of the force-time curve, respectively. Paired samples t-tests were used for pre-post comparisons. Results: Mean RT for the PVT was reduced (p = 0.08–0.12) for post-vs. pre-test scores. No differences were observed for double-leg balance scores (p = 0.35); however, single-leg balance was reduced at post-test (p = 0.01). RFDpeak was lower (p = 0.01), whereas PF was not different (p = 0.20), for post-vs. pre-test strength-related scores. Conclusions: Demanding multi-shift nursing work yielded moderate-to-large performance reductions for vigilance-based RT (9.2%), static single-leg balance (31.6%) and explosive hand grip strength (11.9%); which both reflects the presence of fatigue as well as provides sensitive identification tools for revealing work-related fatigue. Practical Applications: Performance testing involving rapid response vigilance tasks, explosive strength, and more challenging balance tasks, may be utilized to identify the presence of fatigue in workers undergoing long, rigorous work periods. The monitoring of such performance declines may provide useful solutions for the early detection of risks for fatigue-related injuries in healthcare workers.
Body Image Perception and Muscle Dysmorphia in Adolescent Males
K. Skemp, R. Elwood, J. Erickson, R. Kacvinsky, and E. Krueger
University Wisconsin-La Crosse
An identified disorder called Muscle Dysmorphia (MD) has emerged within the male population that is marked by a disruption in body image with extreme body dissatisfaction and a drive for muscularity that leads to compulsive behaviors to attain an ideal body shape. Purpose: The primary purpose of this study was to assess the level of body image dissatisfaction (BID) among male adolescents and whether or not BID was correlated with behaviors associated with MD. A secondary purpose was to examine if a difference exists between athletes and non-athletes. Methods: The Eating Attitude Survey (EAS) was used to assess attitudes toward body weight and shape while the Muscle Dysmorphia Inventory (MDI) was used to assess the behavioral and psychological characteristics of muscle dysmorphia among male adolescents (N = 149, mean age = 15.01 ± 1.85 years, and mean BMI = 23.26 ± 5.01 kg·m−2). The EAS identified whether or not an individual was satisfied with their body weight and body shape with “yes or no” questions. The MDI contains 6 subscales (dietary behavior, supplement use, physique protection, exercise dependence, body size/symmetry, and pharmacological use) and each subscale contains questions that are answered with a 6-point Likert scale ranging from “never” to “always.” Each subscale score for this study was calculated by summing all item scores for the subscale. Higher scores were associated with MD behaviors and potential risk for MD. Independent t-tests were used to test for differences in the population means among subscales at a 0.05 level of significance. Results: Overall, individuals who were dissatisfied with their weight (26.8%) scored significantly higher on both Physique Protection (Mean = 14.36 ± 5.5 vs. 11.62 ± 5.2, p = 0.012) and Size/Symmetry (15.42 ± 6.1 vs. 12.59 ± 5.4, p = 0.015) subscales than those who were satisfied with their weight. Moreover, those who were dissatisfied with their body shape (29.5%) also had significantly higher scores on the Size/Symmetry (16.14 ± 6.0 vs. 12.01 ± 5.1, p < 0.0005) subscale than those who were satisfied with their body shape (Table 1). Further results indicated that 29.6% of athletes (N = 98) were dissatisfied with their body weight vs. 21.6% of non-athletes. Regarding body shape, 32.7% of athletes were dissatisfied vs. 23.5% of non-athletes. Conclusions: This sample of male adolescents indicate some level of body image dissatisfaction which is also associated with overall higher scores for all subscales of the MDI, but especially the subscales relating to muscularity. Athletes in particular showed higher levels of body image dissatisfaction and therefore, attention to this population is indicated. Practical Applications: Coaches, trainers, and health professionals need to be aware of the signs of body image dissatisfaction as well as the behavioral characteristics of MD or any other compensatory behaviors to modify body weight and shape. Awareness allows for early intervention through education and communication so as to prevent and/or reverse MD in the adolescents they serve.
Comparison of Younger and Older Adults while Dual-Tasking on Selected Gait Parameters
S. Paulson, J. Sanders, R. Shaw, H. Schmuck, M. Butler, and J. Desire
Shippensburg University of PA
Changes in gait parameters have been noted when performing an attention-demanding task while walking. The increased need for attention to perform the working memory task may elevate the fall risk for an older adult. Purpose: This study examined the effects of dual-tasking on selected gait parameters in younger and older community-dwelling adults. Methods: Twenty younger (M ± SD = age: 21.20 ± 1.20 years; mass: 69.43 ± 14.95 kg; height: 1.67 ± 0.15 m) and 23 older (M ± SD = age: 71.13 ± 4.25 years; mass: 84.59 ± 17.18 kg; height: 1.71 ± 0.10 m) adults volunteered to complete 2 walking trials (20 m) for each condition: habitual walking (HAB) and habitual walking with a working memory task (DT). During the DT, subjects were instructed to count down by 3 from a given value. The order of the trials was randomized and counter-balanced. Selected gait variables were measured with a gait mat placed in the middle of the 20 m walkway. Data were analyzed using a 2 × 2 repeated measures ANOVA. Results: The M ± SD of the gait variables measured by group and condition are presented in Table 1. There was a significant main effect for task condition on gait speed (p < 0.01), step frequency (p < 0.01), double-support time (p < 0.01), and step length (p < 0.01) independent of the age group. Further, a significant interaction was yielded between task condition and age group for double-support time (p = 0.05). A significant main effect for age group was shown for all gait variables (p ≤ 0.05) except step frequency (p = 0.09). Conclusions: Both younger and older adults demonstrated significantly, less favorable changes in gait related variables during while dual-tasking. The older adults showed greater performance decline than the younger adults across all variables measured. This may increase fall risk for an aging adult. Practical Applications: Health fitness professionals may want to include dual-task training exercises within an exercise program for younger and older adults. In particular, identifying dual-task situations, which are problematic, and designing an exercise intervention would be particularly advantageous for older adults.
Tool for Measuring Intensity Between Training Sessions in Elderly
F. Martin,1 A. MartinsPedrosa,2 J. Casaña,1 J. Carrasco,1 A. Teixeira,3 and J. Colado1
1University of Valencia; 2University of Valencia; and 3University of Coimbra-Portugal
There is still a need to find valid methods of monitoring the global training intensity during resistance training with new devices, and even more when they are applied in special populations, as it is the case of elderly. So it is a priority to identify if it is possible to monitor the intensity of resistance training exercises between sessions when using devices that cannot show directly the load of training, as for example when elastic bands (EB) are employed. Purpose: To determine the reliability of the session RPE method, using the Thera-Band resistance exercise scale, for quantifying the intensity of resistance training with elastic bands in elderly. Methods: Twenty-six healthy, physically active and older adults subjects (5 male and 21 female) participated in a familiarization session with the procurements and devices and in 2 more identical sessions of measurement, all of them separated by at least 48 hours. In each measurement session, after a standardized warm-up, the subjects performed 3 separate sets of 15 repetitions for the exercises applied (shoulder abduction, elbow flexion, extension and abduction of the hip). One set was performed with an elastic band width grip that allowed the subjects to perform 15 maximum repetitions (15RM grip) in the selected exercise; another 2 sets were performed with a width grip 25 and 50% more than the 15RM grip. The order in which the exercises were carried out was counterbalanced. In the same way, the order in which the different sets were performed according to their intensity was randomized for the measurement sessions. Ative muscle (AM) and overall (O) ratings of the perceived exertion (RPE) were collected in the 2 measurement sessions from the OMNI-RES scale with EB immediately following the final repetition of each set of each exercise of all the different intensities analyzed. Finally, the reliability of the RPE scores was checked by means of intraclass correlation coefficient (ICC) and standard deviation (SD). Results: The inter-session reliability analysis showed moderate-good ICC for AM (0.78; SD = 0.05) and O (0.68; SD = 0.07) RPE scale scores. Conclusions: The session RPE method of quantifying resistance training using the Thera-Band resistance exercise scale with older adults was shown to be a reliable measurement tool for monitoring the intensity across 2 different EB training sessions, if applied in an appropriate manner to generate the training stimulus. Practical Applications: This study is showing the possibility of changing easily and efficiently the resistance training stimulus in elderly. So, the findings of this study could have significant implications in clinical, wellness, and recreational prescription when resistance training programs with elastic bands must be employed in elderly population.
The Influence of Short Duration Low Intensity Whole Body Vibration on Low to Moderately Active Older Adults: Pilot Study
C. Proulx,1 A. Haggerty,2 D. Laing,3 R. Carmichael,1 and J. Roethlingshoefer4
1Plymouth State University; 2UMASS; 3Westfield State University; and 4Miami University
Introduction: In the ageing population, there are certain medical and health concerns that are directly related to losses of neuromuscular skeletal function. Loss of both strength and balance are large contributors to falls, leading to disability and increased health care costs. The loss of certain function may also contribute to a lower exercise intensity and duration, further perpetuating to the loss and increase the risk of injury. This may be overlooked in individuals with some degree of mobility and function and result in lack of appropriate progression in a physical activity program supervised or unsupervised. Whole body vibration has been used on either end of the functional capacity spectrum of function, including sedentary diseased population to elite athletes. Purpose: As an initial investigation, the intent is to determine the benefit, if any, on functional and performance parameters in low to moderate activity older adults. Methods: The study was a single trial within subject design. The study took place in the clinical laboratory at a University. Subjects (n = 9) were men and women healthy volunteers greater than the age of 55 who attended a regular open walking session at the University. All subjects were screened for contraindications in both the testing and application of whole body vibration. All subjects were assigned to the same testing protocol, and completed a warm-up prior to testing. The treatment protocol consisted of six 30 seconds bouts of WBV (f = 30 Hz, amplitude 2 mm), with 1 minute rest in between. A bench was provided in front of the participants, in the event he or she should lose his or her balance and need support. The 2 factors being measured for the purposes of this study were functional mobility and balance. Timed-Up-and-Go (TUG) test was used to determine changes in functional mobility, and the Balance Error Scoring System (BESS) was used to determine changes in balance. All measures were taken at baseline, and immediately after the intervention period. T-test was used to determine effects. Results: There were significant improvements in TUG scores (p = 0.01), non-significant improvements in BESS eyes-open scores (p = 0.22), and non-significant improvements in BESS eyes-closed scores (p = 0.11). Both BESS scores yielded percent changes 17.14 and 7.64% improvement for eyes open and eyes closed positions, respectively. Average percent change in TUG was 9.24%. Practical Applications: As with highly functioning individuals, the changes can be performance enhancing. This particular group, although not highly functioning, are approaching the age were changing in progression may continue to decline. Whole body vibration may provide an additional stimulus to maintain current mobility levels, or increase. Further studies are needed to determine if the acute responses can become part of a long term adaptation. This may provide programs with an opportunity improve functional capacity with little effort and given the relative safety and current utilization, appears to be a modality for exercise training that may be used through a continuum of training.
Shoulder Mobility Characteristics Among Recreational Weight-Training Participants With and Without Impingement Syndrome: A Preliminary Analysis
M. Kolber,1 W. Hanney,2 S. Cheatham,3 B. Schoenfeld,4 and P. Salamh5
1Nova Southeastern University; 2University of Central Florida; 3California State University; 4CUNY Lehman College; and 5Duke University School of Medicine
Purpose: The shoulder complex accounts for up to 36% of all recreational weight training (RWT) injuries and disorders. While the underlying etiology of shoulder pain among RWT participants is multifactorial, subacromial impingement syndrome (SIS) is often implicated. Although recent evidence has identified prescriptive training patterns associated with SIS, a paucity of evidence exists to describe intrinsic risk factors. The purpose of this study was to investigate and compare specific risk-related mobility adaptations among RWT participants who were asymptomatic to those identified as having SIS. This comparison was based on a previously validated clinical testing cluster (Positive Hawkins-Kennedy and Painful Arc Test) with a diagnostic positive likelihood ratio of 5.0. Methods: Forty-five men (mean age, 27.9) with a minimum RWT experience of 2-days per week were recruited, including 14 individuals identified as having SIS (positive pain response on both Hawkins-Kennedy and Painful Arc tests) and 31 without SIS (negative testing cluster) to serve as controls. Following consent, goniometric active range of motion (AROM) was compared between groups for a total of 4 measurements including flexion, abduction, external and internal rotation (IR). AROM procedures were performed based on established measurement guidelines for shoulder goniometry. Independent t-tests were used to compare AROM differences with alpha = 0.05. Results: SPSS version 15.0 was used for analysis. Significant group differences were present as RWT participants with SIS had significantly decreased IR AROM (p = 0.008) when compared to RWT participants without SIS (60.1 ± 9.9° vs. 67.4 ± 7.4°). Significant differences were not identified (p ≥ 0.35) for flexion, abduction and external rotation among this cohort (Table). Conclusions: Shoulder AROM measures were similar for those with and without SIS with the exception of shoulder IR. Reduced shoulder IR, as identified in this investigation among participants with clinical signs of SIS, is not without consequence. Impaired IR has been associated with and predictive of shoulder disorders in both the general and athletic population. Practical Applications: Strength and conditioning professionals should be aware of these findings particularly in the context of exercise prescription. Inclusion of stretching based interventions to mitigate an IR loss may serve as a useful means to mitigate adaptations associated with SIS. Future prospective trials on larger cohorts are needed to investigate a causative and predictive association.
The Incidence of Injuries in the Texas A&M Corps of Cadets′ First Brigade Over the 2013–2014 Academic Year
J. Carter,1 G. Darling,1 H. Hopkins,1 S. Currenti,1 N. Ono,1 C. Goodenough,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: Military readiness is dependent upon the ability of military personnel to be deployed at a moment's notice, which requires our troops to be injury free. Purpose: To determine the incidence of injuries in the Texas A&M Corps of Cadets (CoC) over the Fall (F) and Spring (S) semesters during the 2013–2014 academic year. Methods: During the F and S semesters, the research team monitored the injury profile for first Brigade in the CoC. Throughout the study, when a cadet could not participate fully in physical training (PT) with their unit, they would fill out an injury questionnaire (QS) designed by the research team. After fully returning to PT, the cadets would return and complete the QS. Results: On average, first Brigade consisted of 196 cadets. During the year, 74 QSs were completed (56 in the F; 18 in the S). Males completed more overall QSs (50) compared to the females (24) throughout the year. However, the females had a higher incident rate for injuries (96.0 vs. 29.9%). Freshmen had the highest injury rate (52.7%) followed by sophomores (21.6%), juniors (13.5%), and seniors (12.2%). Similar injury incidences were of cadets who were not seeking military commission (52.7%) to those who were seeking commission (47.3%). The CoC PT accounted for 27.0% of the injuries, and 33.8% of the injuries resulted from reinjuring a prior injury. During the year, 14 cadets missed training on several occasions due to various injuries, and 40.5% needed to seek professional medical evaluation. Conclusions: To reduce injuries in the CoC, emphasis should be placed on educating the training cadre that cadets are most likely to become injured in the F semester for the freshmen class, especially the female cadets. Practical Applications: A major predictor of future injuries is prior injuries. Therefore, emphasis should be placed on preventing injuries from occurring. 47.3% of the injuries occurred by those seeking military commission, thus potentially impairing future military readiness. The majority (52.7%) of the injuries were sustained by the freshmen class, females had the highest injury rate, and both were associated with lower fitness levels. Greater emphasis should be placed on the PT of the incoming freshmen over the summer.
The Type of Injuries Sustained in the Texas A&M Corps of Cadets′ First Brigade Over One Year of Training
G. Darling,1 J. Carter,1 H. Hopkins,1 S. Currenti,1 N. Ono,1 C. Goodenough,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: Over the last several years, the military has placed greater emphasis on injury reduction for our troops. The first step in injury prevention is injury surveillance. Purpose: To determine the type of injuries sustained for the Texas A&M Corps of Cadets' (CoC) first Brigade. Methods: This study occurred over the 2013–2014 academic year for the CoC. When a cadet could not participate in their physical training (PT), they reported to the research team to fill out an injury profile questionnaire designed specifically for the CoC. Results: Injuries were sustained for the cadets' muscles (21.6%), joints (31.1%), bones (6.8%), skin (4.1%), and tendons/ligaments (27.0%). Only 1 cadet, experienced heat illness, and 21.6% of the cadets missed training due to an illness. Of the 16 cadets that experienced muscular injuries (21.6%), there were injuries reported for the triceps surae (4), quadriceps (2), hamstrings (5), lower back (2), abdominal muscles (2), pectoralis major (1), upper back (1), and upper arm (1), with no one experiencing injuries to their gluteal, lower arm, or neck regions. Of the 23 cadets (31.1%) who injured their joints, injuries were reported for the ankle (17), knee (10), hip (2), lumbar spine (2), thoracic spine (1), and glenohumeral (1) joints, with no injuries occurring for the elbow, wrist, or cervical spine. Conclusions: The knee and ankle joints/musculature seem to be prone to injuries for the CoC. This is primarily the result of the running volume, running while in formation, running in poorly lit areas on uneven ground, and running in boots, especially for the freshmen class. Practical Applications: Emphasis should be placed on running conditioning/progression over the summer. Furthermore, running in boots prior to joining the CoC will help adapt the body to the increased load of running in boots. Lastly, running in formation requires the cadet to be able to react quickly to obstacles due to the impaired visibility of running. Cadets should engage in agility, balance, and proprioceptive training to improve their reactive ability.
Relationship of Injuries in the Texas A&M Corps of Cadets to the Exercise Inventory Readiness Questionnaire
S. Currenti,1 G. Darling,1 J. Carter,1 H. Hopkins,1 N. Ono,1 C. Goodenough,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: Research indicates freshmen (FM) cadets are more likely to become injured compared to upper classmen (UC). The Exercise Inventory Readiness Questionnaire (EIRQ) is a 15 question survey to determine if an individual should increase their training volume-load. Purpose: To investigate the differences between injured FM and UC cadets of first Brigade in the Texas A&M Corps of Cadets (CoC) using the EIRQ. Methods: When a cadet could not participate in training due to an injury during the (Fall2013) semester, they would complete an injury questionnaire, which contained the EIRQ. Results: There was a significant (p < 0.01) difference between the total scores for the EIRQ between UC (23.3 ± 4.1) and FM (26.1 ± 3.5). Furthermore, there was a significant difference (p ≤ 0.05) between perceived diet (UC, 1.8 ± 0.8; FM, 2.5 ± 0.8), self-image (UC, 1.2 ± 0.4; FM, 1.5 ± 0.7), and major life changes (UC, 1.6 ± 0.9; FM, 2.4 ± 0.9) for the UC and FM. There was no statistical (p > 0.05) difference between the sleep habits, joint pain, relaxation/energy levels, exercise load changes, the way the cadets felt their body was handling the training, outlook for the Corps, enjoyment of responsibilities, and perceived stress levels, between the UC and FM using the EIRQ. Conclusions: The majority of the injuries sustained in the CoC are the FM. Using the EIRQ, it appears the FM should not increase their training volume-load as rapidly as the UC. Furthermore, using the EIRQ, it appears that the FM class dietary practices are less optimal than the UC. Practical Applications: To reduce injuries in the CoC, nutrition should be addressed during Freshmen Orientation Week for the CoC. Whether or not participating in the CoC improves the self-image of cadet is yet to be determine. However, the UC had a higher score for their self-image, which could be partly due to the fact that the FM indicated that they significantly had a higher score for major life changes. Future research should compare injured to non-injured cadets for the CoC.
Non-Exercise Related Stress Factors for Injured Cadets in the Texas A&M Corps of Cadets First Brigade
H. Hopkins,1 G. Darling,1 J. Carter,1 S. Currenti,1 N. Ono,1 C. Goodenough,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: With proper training, a cadet will improve their fitness capacity. However, as their fitness increases from training, so does their fatigue level. Furthermore, additional life stresses add to the fatigue of a cadet, thus decreasing recovery, mood, and immunity. Purpose: To investigate the non-exercise related stress factors for injured cadets in the Texas A&M Corps of Cadets (CoC). Methods: Over the 2013–2014 academic year, when a cadet was injured in the first Brigade of the CoC, they completed an injury questionnaire that investigated the non-exercise related stress factors. Results: The injured cadets averaged 14.9 ± 1.8 college credits and 5.8 ± 1.6 college courses per semester. Using independent sample T-Tests, there was no significant (p ≤ 0.05) difference between sleep habits between the freshmen and upper class (UC, 2.5 ± 0.7; FM, 2.5 ± 0.8), with 83.8% of the cadets not receiving the recommended amount of sleep (i.e., 7–8 hours per night). 60.8% of the cadets indicated they received ≤6 hours of sleep the night before becoming injured. 24.3, 36.5, 21.6, 12.2, and 4.1% stayed up past midnight the week before on 1, 2, 3, 4, and 5 occasions, respectively. The week before the injury 52.7, 36.5, and 9.5% reported 1, 2, and 3 major assignments/test, respectively. Conclusions: Future research should investigate if there is a difference in the non-exercise related stress factors between the injured and non-injured cadets, as well as determine if cadets' stress capacities increase while in the CoC. Practical Applications: Future research should track the cadets throughout their tenure in the CoC to see if their stress capacity increases. Regardless, life stress will be a part of the CoC, especially if the cadet chooses to pursue a military career. Research has shown that educating individuals on stress management can reduce injures and overtraining syndrome. Therefore, education on stress management and recovery strategies should be incorporated into the CoC, especially for the FM.
The Physical Training Practices and Demographics of Cadets Who Become Injured in the Texas A&M Cadets
N. Ono,1 G. Darling,1 J. Carter,1 H. Hopkins,1 S. Currenti,1 C. Goodenough,1 R. McDaniel,1 K. Brooks,2 L. Greenwood,1 and M. Greenwood1
1Texas A&M University; and 2Alpha Biomedical
Introduction: Too little, too much, and improper physical training (PT) is associated with increased injuries in the military. Purpose: To investigate the PT practices of the injured cadets of Texas A&M Corps of Cadets (CoC). Methods: The study occurred over the 2013–2014 academic year for first Brigade in the CoC. When a cadet was unable to participate in their PT due to an injury or illness, they would complete an injury profile questionnaire designed for the CoC to investigate their PT practices. Results: 40.5% of the cadets engaged in PT while being in pain prior to sustaining from PT. 39.2% of the injuries came from the unit A2, which was the unit with the lowest fitness capacity. Of the CoC special units, injuries were most associated with Rudder's Rangers (12.2%) and Darling Recruiting Company (10.8%). 83.8% engaged in additional training outside of the CoC. 74.3 and 27.0% indicated they engaged in high school sports and a high school ROTC program, respectively, with 31.1% currently playing intramural sports. 10.8, 13.5, and 54.1% of the cadets did not engage in any sort of PT, jogging, and resistance training, respectively over the summer. Conclusions: Cadets must perform PT during the summer months. It appears that in order to increase their scores for the CoC PT test after summer break, the cadets dramatically increase their training load in efforts to seek rapid progressions in their fitness. Practical Applications: Based on our unpublished data, it appears the returning cadets significantly decondition over the summer. To increase their fitness scores, returning and incoming cadets abruptly increase their training load, thus promoting injuries. Furthermore, the freshmen class is associated with lower fitness capacities than the upper class. 10.8% of the injured did not participate in any PT during the summer. It is of the utmost importance that the cadets perform PT during the summer months to reduce injuries.
Non-Linear Periodization Training for a Female Firefighter: A Case Study
C. Burleigh,1 J. Ramirez,1 J. Bennett,2 M. Kolber,3 C. Rothschild,1 and W. Hanney1
1University of Central Florida; 2Seminole County Fire Department; and 3Nova Southeastern University
Purpose: Significant physical demands exist for female firefighters to perform required duties. A structured conditioning program may better prepare these individuals to perform at a high capacity and potentially avoid injury. Therefore, the purpose of this case study was to safely implement a 4-week nonlinear periodization training program in a healthy female firefighter, observe, collect and report data. The training model is based on current principles of strength and conditioning utilizing the 3 metabolic pathways: ATP-PC, glycolysis, and aerobic systems, which are all used during physical activity or firefighting tasks. Methods: A fitness trainer from the Orange County Fire Rescue Department (OCFRD) received a training manual, a 3 hour course covering the training program and its purpose, and demonstration of each exercise using proper form. A female firefighter volunteered and provided informed consent to participate in a 4-week undulating training program: one unsupervised day of aerobic exercise and two 30–45 minutes days of strength and power training. The training program consisted of a combination of functional firefighting tasks and traditional exercises such as the ceiling breach, ladder raise and deadlift. Physical fitness measures including the Incumbent Physical Ability Test (IPAT), push-ups, 300 yard shuttle run and Gerkin treadmill protocol were taken at baseline and after the 4-week program. The IPAT is used by the OCFRD as part of a physical fitness requirement for being a firefighter and measures physical ability and performance as it relates to job-specific activities. The IPAT contains 9 events that must be completed in under 10 minutes. Prior to starting the training and assessment sessions the subject's vitals were taken and a 5 minute callisthenic warm up was completed. A 10 minute cool down was implemented after each training session along with vitals being recorded at the end. Results were monitored for any changes. Results: At the end of 4 weeks the participant demonstrated improvements on the IPAT (decreased time by 1 minutein 17 seconds), and push-up test (increased by +6reps). No change occurred on the 300 yard shuttle run while the maximal oxygen uptake (V[Combining Dot Above]O2max) from the Gerkin test revealed a decrease (−58 seconds). Conclusions: This firefighter was able to safely perform a nonlinear periodization training program which resulted in an improved IPAT time and an increase in number of pushups completed. No change was observed on the 300 yard shuttle run. The V[Combining Dot Above]O2max prediction measured by the Gerkin test was inconclusive due to the participant not reaching her heart rate maximum. Previous research suggests that the Gerkin Treadmill Protocol lacks validity and tends to overestimate V[Combining Dot Above]O2max prediction. The test was chosen due to the fire department using it as part of their physical assessment and the subject's familiarity to the test. The results are to aide in the collection of data determining whether the implementation of a nonlinear-periodized training protocol can be effective in improving the physical fitness level of a female firefighter. Due to being a single case study, further studies need to be completed with a larger sample size and longer duration of training. Four weeks of fitness training does not provide enough time for the body to completely demonstrate the physiological effects associated with exercise. In addition the Gerkin protocol does not reflect a valid assessment of aerobic capacity as determined by previous research. Practical Applications: Physical fitness plays an important role in the performance of firefighters while actively engaged in job-related activity and duties. Conditioning the body for activities that involve all 3 metabolic systems while providing power, muscular strength and endurance is essential. Providing a structured training program to address these components during job activities required of a firefighter may be beneficial.
Application of a Non-Linear Periodization Program Among Firefighters Returning to Full Duty From an Injury
J. Ramirez,1 C. Burleigh,1 J. Bennett,2 M. Kolber,3 P. Pabian,1 and W. Hanney1
1University of Central Florida; 2Seminole County Fire Department; and 3Nova Southeastern University
Purpose: After injury, firefighters are routinely discharged back to work without a return to work conditioning program. While these individuals may be fully functional for everyday activities it does not imply they are physically prepared to return to the high demands of firefighting. The purpose of this case series was to observe changes in physical performance following an 8-week non-linear periodization training program in firefighters returning to full duty from an injury. Methods: Two firefighters cleared for full duty by a physician underwent an 8-week nonlinear periodization program (2 supervised and 1 un-supervised session per week). Participant 1 was recovering from ACL reconstruction and Participant 2 was recovering from a low back injury. The training program consisted of a combination of functional firefighting tasks (i.e., ladder raise, kneeling hose pull, ceiling breach maneuver, etc.) and traditional exercises (i.e., deadlift, lunges, pull-up, etc.). Physical performance was assessed at baseline, 4 weeks, and 8 weeks using the Incumbent Physical Ability Test (IPAT), Push-up test, 300-yard dash, and Gerkin protocol. Each supervised training and assessment session was preceded by vitals and a dynamic warm-up and terminated with a cool down and re-check of vitals. The program was conducted at the Orange County Fire Rescue Department Fit Pit in Orlando, Florida. Certified Peer Fitness Trainers worked with participants during each supervised session and conducted all assessment tests with supervision of the researchers. All trainers were hired by the Orange County Fire Rescue Department and attended a 3-hour orientation prior to the start of the program. Results: Participant 1 showed improvements on the IPAT: 7 minutes 14 seconds (decreased time by 90 seconds), push-up test: 17 (+13 push-ups), and 300 yard dash: 1 minute 28 seconds (decreased time by 9 seconds). Participant 2 showed improvements on the IPAT: 7 minutes 56 seconds (decreased time by 160 seconds), push-up test: 41 (+12 push-ups), and 300 yard dash: 1 minute 32 seconds (decreased time by 11 seconds). Both participants showed no change in Gerkin protocol. Both firefighters were able to return to unrestricted duty. Conclusions: Results of this case series suggest that an 8-week non-linear periodization program yields improvement in performance of firefighting tasks, muscular endurance, and anaerobic capacity as evidenced by improvements in the IPAT, push-up test, and 300-yard dash. Aerobic capacity remained unchanged for both participants as evidenced by both participants unable to reach maximal heart rate during the Gerkin protocol. Both participants stated overall satisfaction with the program. The results do not prove any causal relationship between this non-linear periodization program and improvements in physical performance. Further studies need to be done utilizing a control group, a larger sample size, and potentially using submaximal heart rate for the Gerkin protocol to measure aerobic capacity in order to determine the efficacy of this type of program among injured firefighters returning to full duty. Practical Applications: Results of this case series suggest that a training program incorporating firefighter tasks is appropriate for firefighters returning to full duty from an injury, given the high demands of this occupation. Moreover, the results suggest that at the time of medical clearance to return to duty, individuals may not be at their needed physical performance level given changes in the aforementioned tests. Orange County Firefighters are required to complete the IPAT in less than 10 minutes every year; therefore improvements in IPAT score are promising results of this training program.
Effect of a Single Bout of Heavy Resistance Training on Subsequent Fire Ground Performance
M. Abel,1 N. Triplett,2 J. Dawes,3 R. Pettitt,4 R. Pawlak,5 and K. Havener2
1University of Kentucky; 2Appalachian State University; 3Beth-El College of Nursing and Health Sciences, University of Colorado-Colorado Springs, Colorado Springs, CO; 4Minnesota State University, Mankato; and 5Miami Township Fire and EMS
Purpose: Firefighting is an occupation that requires sufficient physical fitness levels to complete strenuous fire ground tasks. As such, regular participation in exercise is advised to maintain physical fitness. However, it has recently been demonstrated that performing circuit training exercise on-duty reduces firefighters' work rate. These findings raised concerns regarding the effects that different training modes and intensities have on subsequent fire ground physical ability. A better understanding for the time course of recovery from an exercise bout would guide best practices when developing appropriate training programs for firefighters while on- and off-duty. The present study examined the effect of a single bout of heavy resistance training on the work rate of fire ground tasks performed immediately after and 24 and 48 hours post-exercise. Methods A simulated fire ground test (SFGT) was used as a proxy measure of actual work performed during firefighting. The SFGT was composed of the following tasks: stair climb, charged hose drag, equipment carry, ladder raise, forcible entry, search, and rescue. Twelve male firefighters (mean ± SD, Age: 36.5 ± 7.1 years; Relative body fat: 17.1 ± 3.7%; V[Combining Dot Above]O2peak: 42.3 ± 3.8 ml·kg−1·minute−1) were timed while performing the SFGT. Firefighters wore personal protective equipment and used a self-contained breathing apparatus during the SFGT. The firefighters performed the SFGT twice for familiarization purposes prior to the official trials (ICC = 0.97). The SFGT was then performed 4 times as follows: baseline, 10 minutes post-exercise, 24 hours post-exercise, and 48 hours post-exercise. The order of baseline vs. post-exercise SFGT trials was randomized and counterbalanced. The relative loads used during the heavy resistance training session were standardized to the 5 repetition maximum (5RM) for kettle bell swing, deadlift, bench press, bent over row, and shoulder press. The exercise session consisted of performing 4 sets of 5 repetitions at the 5RM load for each exercise with 2 minutes recovery between sets. Blood lactate and rating of perceived exertion (RPE) were measured before and after the exercise session and SFGTs. Repeated measures ANOVA was used to compare the completion times of the post-exercise SFGT trials to baseline. Results: Time to complete the SFGT 10 minutes post-exercise increased by 7.0 ± 7.5% compared to the baseline SFGT (p = 0.01; Cohen's d = 0.48). Time to complete the SFGT 24 hours (0.6 ± 3.9%; p = 0.73; Cohen's d = 0.03) and 48 hours post-exercise (−0.3 ± 3.6%; p = 0.71; Cohen's d = −0.03) were similar to the baseline SFGT. There were no differences in blood lactate and RPE following the SFGT trials (p ≥ 0.44). Pre-SFGT blood lactate was higher than baseline following the exercise session trial (3.5 ± 0.8 vs. 1.9 ± 0.7 mmol·L−1; p = 0.001). Conclusions: Performing heavy resistance training exercise while on-duty decreases firefighters' work rate with minimal effect on most firefighters' work rate 24 and 48 hours post-exercise. Practical Applications: Firefighters should use discretion when performing heavy resistance training exercises while on-duty or perform heavy resistance training while off-duty.
The Effects of Tabata Training on V[Combining Dot Above]O2max
J. Hornsby, J. Schoffstall, M. Bowles, A. Mackenzie, J. Morelli, M. Thornton, M. Allgood, and A. Bosak
The effectiveness of high-intensity interval training programs has been effective in animal models, but there are some contradicting reports as to their effectiveness in humans. Some studies make the case that, for the average individual, interval training is more harmful than helpful, while others show numerous positive effects of interval training for different populations. Purpose: The purpose of this study examined the effects of Tabata training on anaerobic threshold and V[Combining Dot Above]O2 for healthy college-aged students after a 3-week training program. Methods: Twenty active, low-risk stratified, college-age students were recruited as participants. All participants initially performed a V[Combining Dot Above]O2max test on a treadmill following a Costill-Fox protocol. The participants were randomly assigned to either the control group, which had no modifications to their normal training program, or to the experimental group, which followed a Tabata styled workout for three-weeks. Results: Comparisons were made using paired sample t-tests. The initial V[Combining Dot Above]O2max measurements of the control (42.7 ± 6.2 ml·kg−1·min−1) and experimental (40.8 ± 12.9 ml·kg−1·min−1) groups were not significantly different from one another. After 3-weeks the participants were post-tested using the same max test protocol. Although the control group saw improvements in their V[Combining Dot Above]O2max values, these changes were not statically significantly different. However, the experimental group showed significant improvements in V[Combining Dot Above]O2max (p < 0.005) with a post training V[Combining Dot Above]O2max of 49.5 ± 9.4 ml·kg−1·min−1. Conclusions: Based on the results of this study, it appears that a Tabata styled workout program, performed 3-times per week for 3-weeks may provide a sufficient stimulus to create a significant improvement in V[Combining Dot Above]O2max in healthy college-aged students. Additionally, the participants in the experimental group also were able to function at a significantly higher heart rate before reaching their anaerobic threshold. Practical Applications: The goal of exercise programming is compliance and performing chronic aerobic training over an extended period can lead to difficulty in consistency of program completion. However, incorporating variety (i.e., Tabata training and/or high-intensity interval training) into a cardiovascular training program could improve compliance as well aerobic capacity and anaerobic threshold values. Furthermore, the results of this study can be particularly useful to those in the tactical strength and conditioning community since the exercises performed require little to no equipment and allows for the exercises to be completed in almost any setting. Additionally, programming Tabata style workouts into the larger training scheme adds variety to the training sessions while continuing to work toward the basic goals of the tactical athlete, which is being able to perform at their highest training capacity while either maintaining or improving their aerobic fitness level. Future research should assess the impact of Tabata training on tactical athletes and/or members of the Reserve Officer Training Corps.
Effect of Load Carriage on Tactical Physical Ability and Marksmanship
University of Kentucky
Special Weapons and Tactics (SWAT) operators are specially trained personnel who are required to carry equipment to perform high risk tasks. Given the need to carry this equipment, it is important to understand the potentially deleterious effect that the additional load may have on tactical performance. Furthermore, it is important to identify physical fitness characteristics that are associated with the potential decrement in performance due to the additional gear as these characteristics should be targeted in an exercise program to enhance tactical efficiency during load carriage. Purpose: The primary purpose of this study was to evaluate the effect of load carriage on tactical performance and marksmanship. Secondarily, we sought to identify fitness characteristics that were associated with any observed decrement in performance. Methods: Twelve male SWAT operators (Age: 33.7 ± 5.2 years; Height: 182.2 ± 6.6 cm; Body mass: 92.7 ± 12.9 kg) performed a simulated tactical test (STT) on a live firing range with (loaded condition) and without external equipment (unloaded condition). The STT was composed of 13 individual tasks which were performed in succession without recovery. These tasks included a stair climb, wall climb, barrel shot, standing/prone shot, up-and-go, agility, low crawl, seated shot, rifle drop, door breach, handgun shot, victim rescue, and sprint. The time to complete each task as well as the overall test were recorded. Five of the tasks involved firing multiple rounds at a target. Shooting accuracy was quantified as the average linear displacement from the target's center. Each operator also completed a battery of physical fitness assessments that assessed the following: aerobic capacity, mean and peak anaerobic capacity, lower body power, fatigue index, upper and lower body strength, trunk endurance, agility, upper body muscle endurance, and flexibility. Absolute differences between STT task times in loaded versus unloaded conditions were calculated to create delta times. STT tasks exhibiting significant differences between conditions were correlated with fitness test outcomes. Results: Time to complete the STT in the loaded condition increased by 7.8 ± 5.5% compared to the unloaded condition (Loaded: 206.3 ± 23.8 seconds; Unloaded: 191.4 ± 21.3 seconds; p < 0.001). Nine of the 13 STT tasks were performed significantly slower in the loaded condition. V[Combining Dot Above]O2peak was negatively associated (r = −0.624, p = 0.040) and fatigue index was positively associated (r = 0.639, p = 0.025) with the overall STT delta time. Marksmanship was similar between the unloaded (Accuracy: 5.7 ± 1.7 cm) and loaded conditions (Accuracy: 5.9 ± 2.3 cm; p = 0.816). Conclusions: SWAT equipment decreases tactical work efficiency, but does not affect marksmanship. Aerobic capacity and fatigue resistance are critical fitness characteristics that are associated with the decrement in tactical performance due to performing tasks with gear. Practical Applications: These findings indicate that a higher aerobic capacity and lower anaerobic fatigability are related to a greater resilience to carrying a load while performing tactical tasks. A load carriage training program should utilize exercise strategies that enhance the glycolytic and oxidative energy systems to attenuate the deleterious effects of tactical gear.
Age Differences in Sit-up Performance Amongst Male Law Enforcement Officers
L. Heil, L. Tobin, J. Dawes, and C. Elder
Beth-El College of Nursing and Health Sciences, University of Colorado-Colorado Springs, Colorado Springs, CO
The 1-minute sit-up test is an assessment frequently used amongst law enforcement officers to measure muscular endurance of the trunk. According to the Cooper Institute for Aerobics (Research 2006) this assessment is predictive of the ability to perform essential job tasks for law enforcement officers in most cases. Consequently, this assessment is frequently used by law enforcement agencies as part of their pre-hire selection process, as well as volunteer fitness programs. However, at this time it is unclear whether there are significant differences in performance for this measure amongst officers of different ages. Purpose: Therefore the purpose of this research is to determine whether their significant difference in sit-up performance amongst male law enforcement officers of different ages. Methods: Archival data on the 1-minute sit-up assessment for 522 male law enforcement officers (ages 20–59) from 2 different law enforcement agencies was provided to the primary investigator for analysis. Participants were divided into 4 groups according to their age (group 1: 20–29 years [n = 66]; group 2: 30–39 years [n = 182]; group 3: 40–49 years [n = 236]; group 4: 50–59 years [n = 38]). Using the SPSS 22.0 software package, descriptive statistical analysis was conducted to determine mean sit-up scores for officers in each age category. Additionally, 1-way analysis of variance (ANOVA) with pairwise comparisons were used to compare mean differences in sit-up performance amongst officers in different age categories. Results: Mean sit up scores were: group 1 (Mean ± SD = 39.05 ± 6.9); group 2 (Mean ± SD = 37.57 ± 8.4); group 3 (Mean ± SD = 35.88 ± 8.6); group 4 (Mean ± SD = 34.58 ± 10.5). There was a statistically significant difference in sit up performance for the age groups: F(3, 518) = 3.789, p = 0.01. Pairwise comparisons revealed mean scores for group 1 was significantly different from group 3 (p ≤ 0.01) and group 1 was significantly different from group 4 (p ≤ 0.01). Furthermore, significant differences were discovered between groups 2 and 3 (p ≤ 0.05) and groups 2 and 4 (p ≤ 0.05). Conclusions: Older officers performed significantly different than their younger counterparts suggesting weaker trunk muscular endurance. In many situations all officers are held to the same job criteria regardless of age. Future research should explore age differences among other predictors of job performance. Practical Applications: Due to a law enforcement officer's job requirements, it is important to ensure that older officer's abdominal endurance is maintained throughout their careers. As an officer ages, strength and conditioning professionals are encouraged to include abdominal endurance exercises in their programs to ensure that officers have the ability to perform at optimal levels.
Age Differences In Push-up Performance Amongst Male Law Enforcement Officers
B. Brandt,1 R. Conroy,1 J. Dawes,2 and C. Elder2
1University of Colorado Colorado Springs; and 2Beth-El College of Nursing and Health Sciences, University of Colorado-Colorado Springs, Colorado Springs, CO
The 1-minute push-up test is an assessment frequently used amongst law enforcement officers to measure upper-body muscular endurance. According to the Cooper Institute for Aerobics (Research 2006) this assessment is predictive of the ability to perform essential job tasks for law enforcement officers in most cases. Consequently, this assessment is frequently used by law enforcement agencies as part of their pre-hire selection process, as well as in volunteer fitness programs. However, at this time it is unclear whether there are significant differences in performance for this measure amongst officers of different ages. Therefore the purpose of this research is to determine whether their significant difference in push-up performance amongst male law enforcement officers of different ages. Methods: Archival data on the 1-minute push-up assessment for 518 male law enforcement officers (ages 21–59) from 2 different law enforcement agencies was provided to the primary investigator for analysis. Participants were divided into 4 groups according to their age (group 1: 20–29 years [n = 66]; group 2: 30–39 years [n = 177]; group 3: 40–49 years [n = 234]; group 4: 50–59 years [n = 41]). Statistical Analysis: Using the SPSS 22.0 software package, descriptive statistical analysis was conducted to determine mean push-up scores for officers in each age category. Additionally, one-way analysis of variance (ANOVA) with pairwise comparisons were used to compare mean differences in push-up performance amongst officers in different age categories. Results: Mean push-up scores were: group 1 (Mean ± SD = 46.47 ± 14.62); group 2 (Mean ± SD = 44.65 ± 15.57); group 3 (Mean ± SD = 43.92 ± 15.74); group 4 (Mean ± SD = 43.71 ± 15.09). There were no statistically significant differences in push-up performance between age groups (F(3,514) = 0.505, p = 0.679). Conclusions: Older officers do not perform significantly different than their younger counterparts suggesting similar upper-body muscular endurance levels across the age span. Future research should investigate parameters that might explain the large standard deviations observed in each of the groups. Practical Applications: Maintaining upper body muscular endurance is imperative for officers as they age because their essential job tasks remain the same. Consequently, strength and conditioning professionals should focus on maintaining this attribute to help reduce the physiological burden of job tasks as officers age.
Influence of Compression Garments on Selected Physiological Measures while Traversing Extreme Terrain at Altitiude
J. Dawes and C. Elder
Beth-El College of Nursing and Health Sciences, University of Colorado-Colorado Springs, Colorado Springs, CO
Purpose: Lower-body compression garments (LBCG's) have been used extensively in therapeutic medicine, however in recent years the use of LBCG's as an ergogenic aid has dramatically increased. CG's may be beneficial for conserving high-energy phosphates for subsequent short, bursts of energy and improved repeated performances at high speeds. This finding may also be applicable to the military soldier that often needs to cover short distances as quickly as possible to advance on a designated target or maintain personal safety. Thus, the purpose of this pilot study was to determine the influence of lower-body compression garments (LBCG) on selected physiological measures while traversing extreme terrain at altitude. Methods: Nine (n = 9) recreationally active males (Age: 26.9 ± 4.9; Height: 178.22 ± 5.89 cm; Weight: 85 ± 13.3 kg). Participants participated in 2 testing trials, one trial in self-selected normal active wear and one trial wearing graduated LBCG's made of a circular knit 50 Denier Lycra fabric (2XU, Melbourne, Australia). Participants were then outfitted with a Zephyr Bioharness 3 chest strap (Zephyr Technology Corporation; Annapolis, MD, USA). Participants then performed a 7 km (3.5 km ascent; 3.5 km descent) time trial up the Barr Trail located in Manitou Springs, Colorado. The section of the trail used had a beginning elevation of 1990 m and a peak of 2606 m. Physiological data including heart rate, heart rate variability, estimated core temperature, breathing rate, peak acceleration, physiological and mechanical load, physiological and mechanical intensity, training load, activity level, and estimated caloric expenditure were captured via the Zephyr Bioharness 3. Additionally, muscle soreness ratings at 24, 48 and 72 hours were also collected. A second trial was performed 7 days after the first. The same pre and post-test procedures were followed for each trial, however prior to the start of the second trial participants were outfitted with LBCG'S. Statistical Analysis: Using SPSS 21.0a descriptive statistical analysis was conducted to determine the mean scores and standard deviations for the total sample. Differences in mean scores were determined via a series of Wilcoxon signed rank tests. Results: Significant differences were discovered between trials in physiological load (p = 0.04); training load (p = 0.01); average physiological intensity (p = 0.05) and estimated caloric expenditure (p = 0.02) for the 7 km route. Significant differences were also discovered between trials for the 3.5 km ascent portion of the route in estimated caloric expenditure (p = 0.04). During the 3.5 k descent portion of the route significant differences were discovered between trials in physiological load (p ≤ 0.01); mechanical load (p ≤ 0.01); and average physiological intensity (p ≤ 0.01); average mechanical intensity (p = 0.02); and estimated caloric expenditure (p ≤ 0.01). Furthermore, significant differences were discovered between pain scale ratings at 48 hours (p ≤ 0.01) and 72 hours (p = 0.04) post event with significantly less pain reported after activity in which the LBCG's were worn. Conclusions: LBCG's may help improve physiological performance and perception of pain within 72 hours after intense activity. Practical Applications: Wearing LBCG's during intense physical activity may help reduce the physiological burden experienced during physical activity and lead to reduced perceptions of pain in the days following strenuous physical activity.
The Effects of Post-Exercise Whole Body Vibration With Stretching on Mood State, Fatigue, and Soreness in Collegiate Swimmers
M. Jones,1 M. Tynan,1 A. Jagim,2 and J. Oliver3
1George Mason University; 2University of Wisconsin-La Crosse; and 3Texas Christian University
Purpose: A common post-exercise recovery activity is static stretching (SS). Recently, performing that activity on a whole body vibration platform (WBV + SS) has been promoted as an alternative recovery technique. While athletes self-report enhanced recovery from post-exercise WBV + SS, there is limited published research available supporting such claims. The specific purpose of this study was to compare collegiate swimmers' self-ratings of fatigue, mood state, and soreness between SS and WBV + SS following exercise. Methods: A cohort of NCAA Division I sprint and distance swimmers consisting of 9 women (mean ± SD: 19.3 ± 1.3 years, 171 ± 5.7 cm, 67.6 ± 7.2 kg) and 10 men (mean ± SD: 19.7 ± 1.0 years, 183 ± 5.5 cm, 77.1 ± 4.2 kg) participated in a repeated measures crossover design that included 2 familiarization and 6 data collection sessions. Session 1 consisted of body composition assessment ([BodPod] women: 26.6 ± 4.1% body fat [BF], men: 13.1 ± 2.2%BF). Sessions 1 and 2 included familiarization with: (a) 4 written testing instruments (i.e., brief assessment of mood [BAM], fatigue [FAT], ratings of perceived exertion [RPE], soreness [SOR]), (b) SS exercises, and (c) vertical WBV platform. To assess mood state changes athletes completed the BAM, which measures 6 affective states: (a) tension, (b) depression, (c) anger, (d) vigor, (e) fatigue, and (f) confusion. Subjects were divided by sex and event (sprint or distance) then randomly assigned to SS or WBV + SS. Both the SS and WBV + SS conditions consisted of 15 whole body SS exercises performed on the WBV platform with or without WBV (frequency: 50 Hz, amplitude: 6 mm) over a timed 15-minute period. Sessions 3–5 took place post-practice over a 2-week period. Each session consisted of: pre and post measures of the BAM, FAT, SOR; the condition; and post-protocol completion of RPE. After a 2-week washout period, athletes crossed over and performed the other condition for sessions 6–8 over a 2-week period. A multifactor ANOVA with repeated measures was used to analyze FAT, RPE, SOR, and the 6 BAM affective states between conditions (SS and WBV + SS). Alpha level was set at p ≤ 0.05. Results: There was no difference (p = 0.305) in RPE between the 2 conditions. While there was no difference between conditions in SOR (p = 0.380), WBV + SS elicited lower ratings of FAT compared to SS (p = 0.002) post-exercise. Of the 6 BAM affective states, the WBV + SS condition elicited lower tension (p = 0.031), and fatigue trended toward significance (p = 0.087), while the other 4 BAM measures remained unchanged (p > 0.05). Conclusions: A post-exercise, 15-minute period of WBV + SS reduced self-ratings of fatigue in competitive sprint and distance swimmers. Additionally, a decrease in tension was noted by the BAM and there was a trend for fatigue to improve as a result of the WBV + SS, which is of interest because mood state can be indicative as to how an athlete is adapting to training volume and intensity. The inclusion of WBV + SS did not increase perceived exertion or soreness. Anecdotally, many athletes reported a renewed energy following WBV + SS. Practical Applications: Incorporating a post-workout combined program of WBV + SS may enhance an athlete's ability to recover from exercise.
Organizational Obstacles and Barriers to the Implementation of Appropriate Pre- and Post-Activity Stretching Protocols by Athletic Trainers
J. Popp,1 D. Bellar,2 D. Hoover,3 L. Marcus,2 B. Craig,1 and L. Judge1
1Ball State University; 2University of Louisiana at Lafayette; and 3Western Kentucky University
Current research recommendations for pre- and post-activity stretching are not always implemented by Athletic Trainers (ATs), even though they have completed education and national certification that stress evidence-based practices. A variety of factors can play a role in influencing the stretching practices promoted by ATs in the collegiate setting. Purpose: The purpose of this investigation was to examine the barriers that ATs face in implementing appropriate evidence based pre- and post-activity stretching techniques. Methods: An online survey instrument, validated in previous studies, was emailed to ATs working at all college levels and locations throughout the United States. Results: A total of 432 ATs employed in the collegiate setting completed the survey, resulting in a 15.2% response rate. Nearly half (47.4%, n = 205) of respondents reported that coaches are not aware of current research related to pre- and post-activity stretching protocols, but 63.9% (n = 276) of ATs reported they are aware of such research. Respondents agreed or strongly agreed that coaches are receptive to advice regarding pre-activity (74.3%, n = 321) and post-activity (68.3%, n = 295) stretching protocols. Yet over one third of ATs (39.8%, n = 172) indicated that coaches do not allow ample time for the completion of pre-activity stretching, and over half (56.5%, n = 244) indicated that coaches do not allow ample time for post-activity stretching. Related to this, nearly half of ATs indicated coaches hold a view that pre-activity stretching (48.9%, n = 211) and post-activity stretching (45.5%, n = 196) will take away from valuable coaching/training time. While a majority (51.9%, n = 224) of ATs reported that coaches are open to new ideas that are aligned with current research, 41.9% (n = 181) indicated that coaches are hesitant to revise pre-activity protocols that are outdated and non-compliant with current research. Respondents indicated that coaches instruct athletes to comply with the AT regarding stretching (63.2%, n = 273), but only 47.3% (n = 203) indicate that athletes actually comply fully with the pre-activity stretching protocols and even fewer (35.9%, n = 155) comply fully with post-activity stretching protocols. Conclusions: It appears as though coaches are receptive to pre- and post-activity stretching recommendations given by the AT. However, coaches may not fully appreciate the importance of pre- and post-activity stretching routines in enhancing athletic performance and preventing injury. Furthermore, less than half of athletes are complying fully with the pre- and post-activity stretching protocols recommended by the AT. Practical Applications: As ATs serve in a supportive role in collegiate athletics, they encounter organizational barriers to enacting evidence-based training practices across all sports. Coaches need to be educated on the value of pre- and post-activity stretching protocols and its effects on performance and injury prevention. Furthermore, while it appears that coaches are receptive to the advice of the AT, coaches as sport-specific leaders may not set aside sufficient time or adequately emphasize to athletes necessary to facilitate broader compliance with evidence-based pre- and post-activity stretching protocols.
The Effects of Various Warm-up Protocols on Eight Hundred meter Time in ELITE Male NCAA Division I Runners
B. Wax,1 R. Keesling,2 A. Kavazis,3 and B. Vickers1
1Mississippi State University; 2Mississippi State; and 3Auburn University
Various types of warm-up techniques at various levels of intensity have been reported to improve running performance. However, minimal research has examined what specific type of warm-up technique may have the best effect on 800 m elite athletes. Purpose: The aim of this study was to investigate low, moderate, and high intensity warm-up techniques on 800 m performance in elite track athletes. Methods: Seven NCAA Division I male athletes (age = 22.7 ± 1.7 years, mass = 62.1 ± 3.8 kg, BMI = 20.0 ± 0.08) participated in a randomized and counterbalanced study. Participants were randomly assigned to one of 3 warm-up groups. Upon reporting to the strength and conditioning specialist, each participant performed the assigned warm-up protocol. The low intensity warm-up protocol consisted of a 10-minute jog, dynamic stretching, and stride running. The moderate intensity warm-up protocol consisted of the low intensity warm-up protocol with additional 4 acceleration sprints (40–80 meters) and one 100 m sprint. The high intensity warm-up protocol consisted of the low intensity warm-up protocol with additional 100, 200, and 300 m sprints at race speed with one to 3 minute jogging recovery between each sprint bout. All warm-up periods were followed by a 15-minute rest period prior to the 800 m trial. All trials were separated by a 7 day period. Results: There was no significant difference (p > 0.05) between low, moderate, and high intensity warm-up protocols for the first 400 m completed (low = 62.19 ± 4.61 seconds; moderate = 60.59 ± 3.68 seconds); (high = 59.13 ± 2.84 seconds). However, at the completion of the 800 m time trial, the high warm-up group had a significant (p ≤ 0.05) less time than the low warm-up group (low = 128.98 ± 9.72 seconds; moderate = 125.53 ± 6.92 seconds); high = 122.89 ± 6.91 seconds). Conclusions: These findings suggest that high intensity warm-up may be more prudent for elite level male athletes during 800 m races. Practical Implications: Our data suggests that elite male athletes should consider high intensity warm-up preceding racing distances of 800 m.
Concurrent Effects of Foam Rolling on Flexibility and Sprint Performance
W. Kobetitsch and T. Keating
Background: Foam rollers FR are growing in popularity among athletes as an alternate pre-event modality to enhance flexibility and, perhaps, performance. Research is not, as yet, conclusive on their benefits. Data are particularly scant on the effects of FR on subsequent sprint performance. If it can be demonstrated that use of FR acutely enhances flexibility, while preserving sprint performance, they may be a viable alternative to more traditional preparatory modalities such as static and dynamic stretch. Purpose: The purpose of this investigation was to determine the concurrent effects of FR on acute flexibility and sprint performance. Methods: Ten recreationally trained college males (20.7 + 1.6 years, 177 + 5 cm, 73.5 + 11.3 kg) volunteered for participation in this pretest-posttest design. As previous research, involving static stretch, has often acutely found incompatibility of the 2 dependent measures, a true control group was deemed unnecessary (subjects essentially serving as their own controls). After thorough orientation and standardized warm-up (light jogging followed by submaximal sprint attempts only), subjects performed pretests PRE of 40 yard sprint (best of 3). Sprint times were recorded using an infrared timing system and pressure switch. Importantly, this system eliminated the role of subject reaction time. PRE sit-and-reach SR measures (best of 3) were then recorded from a standard SR box. Sprint always preceded SR to minimize potential static stretch effects. In the same manner, posttests PST were performed after 2 min of slow (3–5 seconds per in), bilateral FR treatment for the hamstrings and quadriceps. A standard 36 in black (high density), cylindrical foam roller was used for all trials, subjects instructed to use increments of body weight to produce mild discomfort. Results: Dependent t tests revealed significant (p < 0.01) improvements in SR (26.3 ± 7.3 PRE vs. 29.2 ± 6.6 PST) with no decrement in sprint performance (5.18 ± 0.27 PRE vs. 5.13 ± 0.28 seconds PST). Conclusions: It can be concluded that FR is an effective way to acutely enhance flexibility while preserving sprint performance in recreationally trained males. Practical Applications: As an alternate pre-event modality to enhance flexibility without compromising short sprint performance, FR may be substituted, by strength and conditioning professionals, for more traditional training modes, though additional research is needed.
Functional Movement Screen Normative Values in Female Collegiate Soccer Players
J. Miller, S. Cook, Z. Perkins, and B. Ziegler
California State University Bakersfield
Injury rates in female collegiate soccer players are very high during the pre-season practices and games compared to in-season practices and games. A pre-participation screening tool that can identify risk for injury may reduce the overall injury rates of the players. The Functional Movement Screen (FMS) is a reliable clinical tool used to predict injuries in athletes. Purpose: The primary purpose of this investigation was to establish normative FMS values for female soccer players. Methods: Sixteen healthy female soccer players (mean + SD, age = 19.5 ± 1.5 years, height = 167.1 ± 4.7 cm, weight = 62.2 ± 4.9 kg) performed all 7 FMS tests and 3 clearing tests. All the players were currently injury free and played collegiate soccer. Results: Descriptive data for FMS scoring can be found in Table 1. A Chi-square test was used to evaluate whether significant differences in scores exist for any component of the FMS. The mean FMS score (score range = 0–21) among the players was 16.1 ± 1.4; 13% of the players had FMS scores 14. No significant differences were found between player position and total score. All athletes scored highest on the active straight leg raise (2.69 ± 0.48) and shoulder mobility (2.63 ± 0.05) while in contrast the players' lowest scoring trials were trunk stability (1.81 ± 0.54) and deep squat (2.06 ± 0.25). Conclusions: This study provides normative values for FMS scores when testing uninjured female collegiate soccer players. Practical Applications: The FMS has been previously demonstrated to be a reliable screening tool in athletes of various sports. The screen can be used in the preseason to determine if a player is at greater risk for injury and can be prehabilitated prior to the beginning of the season. The values found in this study can be used as a reference in comparing FMS scores in other female soccer players who are screened using the FMS.
Effects of p-Synephrine and Caffeine Supplemention on Metabolic Responses During Heavy Resistance Exercise
J. Bush,1 N. Ratamess,1 J. Kang,1 W. Kraemer,2 S. Stohs,3 V. Nocera,1 M. Leise,1 K. Diamond,1 L. Pigott,1 J. Pacifico,1 C. Noonan,1 and A. Faigenbaum1
1The College of New Jersey; 2The Ohio State University; and 3Creighton University
Purpose: To examine the effects p-synephrine and p-synephrine + caffeine on metabolic responses during resistance exercise (RE). Methods: Twelve healthy resistance trained subjects were randomly assigned (double-blinded manner) to a treatment sequence of 100 mg p-synephrine (AZ), 100 mg p-synephrine plus 100 mg caffeine (AZCF), placebo (P), and control (no supplement) (CT) treatment. Separated by 1 week, the RE protocol was completed 4 times consisting of 6 sets of back squats up to 10 repetitions at 80% of maximal strength with 2 minutes of rest between sets at the same time each morning in a fasted state. Subjects consumed each supplement in the form of chews for 3 days prior and upon arrival to the lab the day of each protocol and then washed-out for 3 days following each protocol. Min-by-min O2 uptake (V[Combining Dot Above]O2), respiratory exchange ratio (RER), and ventilation (VE) were measured via a metabolic system (MedGraphics Corp) at baseline (BL), after sitting quiet for 45 minutes after supplementation (BL2), during RE, and for 30 minutes post-exercise (30 PE). A 2-way ANOVA with repeated measures was used to analyze all within-subject data. Results: For V[Combining Dot Above]O2, no significant supplement effect was observed during the BL/BL2 period. AZ and AZCF produced a small (5.8–6.1%) but insignificant (p = 0.16) increase in resting V[Combining Dot Above]O2 during BL2 with some separation observed between the 30–45 minutes period. During RE and 30 PE, no significant (p = 0.15) supplement effects were observed. For VE, no supplement effects were observed during the BL/BL2 period. However, a trend (p = 0.07) for a supplement effect was observed where AZCF tended to be higher than CT and P, and AZ tended to be higher than CT. Significant time and supplement (p = 0.002) effects were observed during 30 PE indicating that AZ and AZCF augmented VE during part (15–20 minutes) of the recovery period. For RER, a trend (p = 0.06) for lower RER vs. P in AZ was observed at BL2. Mean RER of the entire RE and 30 PE did not differ between supplements. Conclusions: AZ and AZCF produced modest increases in V[Combining Dot Above]O2 and RER at rest but did not augment oxygen uptake or RER during resistance exercise. AZ and AZCF tended to increase VE during the entire RE protocol by 3.1–6.5% and this elevation remained through 20 minutes post exercise. Practical Applications: 100 mg p-synephrine supplementation alone and in combination with caffeine tended to increase fat utilization at rest, but did not augment oxygen consumption or RER during resistance exercise.
Friday Abstract Podium Presentations
Friday, July 10, 2015, 8:30 AM–8:45 AM
No Difference in Vertical Jump Relative to Total-Body and Fat-free Mass Between Physically Active Men and Women
K. Allen,1 E. Enquist,1 M. Richardson,1 and M. Esco2
1University of Alabama; and 2The University of Alabama
It is important to consider absolute and relative measures of fitness test scores when comparing men and women. For example, sex-related differences in body mass (BM) and fat-free mass (FFM) may explain significant differences in performance measures of explosive power. However, limited research exploring this possibility exists. Purpose: The purpose of this study was to compare vertical jump (VJ) performance expressed as absolute scores relative to BM and FFM between physically active men and women. Methods: Seven men (age = 21.4 ± 3.1 years) and 7 women (age = 20.9 ± 0.7 years) participated in this study. A calibrated digital scale was used to measure BM. The 3-site skinfold technique was used to estimate body fat percentage which was expressed as a fraction and multiplied by body weight to determine fat-mass. Fat-mass was subtracted from BM to calculate FFM. Following the body composition measures, each participant performed 3 VJs with 1 minute rest between attempts. The maximal VJ of the 3 attempts was recorded. Results: The mean ± SD values for BM and FFM for men were 87.2 ± 11.1 kg and 72.6 ± 7.1 kg, respectively, and for women were 62.3 ± 9.5 kg and 47.1 ± 7.2, respectively. The BM and FFM values were significantly different between sexes (p < 0.001). The mean ± SD VJ scores in absolute units was 57.9 ± 9.9 cm for men and 37.7 ± 8.0 cm for women, which was significant (p = 0.001). When VJ was expressed relative to body mass (0.67 ± 0.10 for men and 0.62 ± 0.16 for women, p = 0.498) and fat-free mass (0.80 ± 0.11 for men and 0.82 ± 0.22 for women, p = 0.821), no significant differences were found. Conclusions: The results of this study suggest that physically active men have significantly greater VJ measures compared to women. However, when expressing VJ relative to BM and FFM, no differences between the sexes were found. Practical Applications: Practitioners need to be aware of sex-related difference in performance measures, such as VJ. Women tend to have lower BM and FFM compared to men, which may partially explain differences in muscular power. Further research is needed with larger sample sizes to explore other variables that fully explain the narrowing gap between men and women when performance is expressed relative to BM and FFM.
Friday, July 10, 2015, 8:45 AM–9:00 AM
A Novel, ATP-Enhancing Supplement Improves Strength, Power, and Body Composition Following a Twelve Week Periodized Resistance Training Program
J. Joy,1 R. Vogel,2 P. Falcone,2 M. Mosman,2 M. Kim,2 and J. Moon2
1Concordia University Chicago/MusclePharm; and 2MusclePharm
Adenosine 5'-triphosphate (ATP) is primarily known as a cellular source of energy. Increased ATP levels have the potential to enhance athletic performance, and one novel supplement has been reported to enhance mitochondrial ATP production. Purpose: Therefore, the purpose of this investigation was to determine the effects of this supplement on body composition and athletic performance when used in conjunction with 12 weeks of supervised, periodized resistance training. Methods: 25 healthy, resistance-trained, male subjects (27.7 ± 4.8 years; 176.0 ± 6.5 cm; 83.2 ± 12.1 kg) completed this study. Subjects supplemented once daily with either 1 serving (150 mg) of a proprietary blend of ancient peat and apple extracts (TRT) or an equal-volume, visually-identical placebo (PLA) 45 minutes prior to training or at the same time of day on rest days. Supervised resistance training consisted of 8 weeks of daily undulating periodized training followed by a 2 weeks overreach and a 2 weeks taper phase. Body composition was analyzed using dual emissions x-ray absorptiometry (DEXA), ultrasound, and bio-electric impedance analysis (BIA). Strength was determined using 1-repetition-maximum (1RM) testing in the barbell back squat, bench press (BP), and deadlift exercises. Power was determined using a linear force transducer during BP at 30% 1RM and vertical jump (VJ) tests as well as a 30 seconds Wingate test. Measurements were conducted at weeks 0, 4, 8, 10, and 12. Results: A group × time interaction (p2); MT increased to a greater extent in TRT vs. PLA from pre to post (TRT: +0.46; PLA: +0.05 cm); squat 1RM increased in TRT vs. PLA from pre to post (TRT: +20.1; PLA: +15.8 kg) as did deadlift 1RM (TRT: +25.4; PLA: +15.2 kg); and VJ PV increased in TRT vs. PLA from pre to week 10 (TRT: +0.15; PLA: +0.05 m·s−1) as did VJ PP (TRT: +229.6; PLA: +113.5 W) which also increased from pre to post (TRT: +253.8; PLA: +192.9 W). No significant interactions were observed for DEXA or BIA-determined lean body mass, fat mass, or percent body fat, BP PP or PV, BP 1RM, or Wingate-determined PP, average power, watt:mass, or average speed, yet Wingate PP (p = 0.059) and watt:mass (p = 0.054) tended to favor the TRT group. Conclusions: Supplementing with the tested proprietary blend of ancient peat and apple extracts while participating in periodized resistance training may enhance body composition and performance adaptations. Additionally, the supplement may protect against the performance decrements associated with overreaching. A lack of effect for upper body performance and whole-body muscle measurements suggest the performance benefits of supplementation may be due to increased muscle hypertrophy of the lower body, which is more likely due to training than a localized effect of the supplement. Practical Applications: This proprietary blend of ancient peat and apple extracts may be used by athletes to enhance strength, power, and muscular hypertrophy adaptations to resistance exercise. The supplement can also be used during training camps or other periods of intense, high-volume exercise to prevent symptoms of overreaching, such as reduced power output.
Friday, July 10, 2015, 9:00 AM–9:15 AM
Do Bilateral Strength and Power Deficits Effect on Ice Sprint Performance in Elite Junior Hockey Players
M. McAndrew,1 J. Winchester,2 F. Wyatt,3 M. Vandehey,4 S. Cronin,3 M. Rogers,5 and W. Jones6
1Wichita Falls Wildcats; 2School of Physical Therapy, University of Incarnate Word; 3Department of Athletic Training and Exercise Physiology; Midwestern State University; 4Midwestern State University; 5Rider High School; and 6University of the Ozarks
Bilateral deficit is a trainable characteristic that occurs when the maximal weight that can be lifted unilaterally by each limb, when summed together, is more than what can be lifted by those limbs bilaterally. As ice skating consists of asynchronous unilateral movements, it may be likely that unilateral (UL) and bilateral (BL) strength and power differences effecting the BL deficits in turn play a role on ice sprinting performance. Purpose: To examine if BL strength and power deficits effect on-ice sprint performance in elite junior hockey players. Methods: In this study, 16 men ([mean ± SD]: age 19 ± 0.8 years; height 179 ± 4.7 cm; mass 84 ± 8.4 kg), were tested for BL strength deficits with BL and UL 1 repetition maximum leg press, for BL power deficits via BL and UL countermovement vertical jumps, and for 34.5-m ice sprints. The strength and power variables measured included BL, UL non-dominant limb, UL dominant limb and BL indexes. Each of these was obtained in an absolute and relative measure. The overall ice sprint time (t), 0–10 minutes acceleration time (a-t), peak acceleration (Pa) and peak velocity (Pv) were used as variables for the ice-sprint. Correlations between the variables were calculated using Pearson product moment correlation coefficient and forward step-wise multiple regression analysis for multivariate correlations. Results: Half of the subjects in this study had BL strength deficits and half had BL strength facilitations. The absolute BL strength index was −2.4 ± 14.2%. All subjects had BL power deficits of −15.0 ± −6.0%. The mean sprint time for 34.5-m ice-sprint was 4.9 ± 0.1 second. There were no significant correlations between sprint variables and either BL strength index or the BL power index. Power (watts) in the BL, UL non-dominant limb and UL dominant limb did show significant correlations with a-t and Pa (r = 0.51, r = 0.52, r = 0.50; p ≤ 0.05) and (r = 0.55, r = 0.58, r = 0.58; p > 0.05), respectively. Forward step-wise regression analyses generated 2 predictive equations: (1) 34.5-m Ice Sprint = 5.366 − (0.273 × Relative Bilateral Strength) + (0.002 × Absolute Bilateral Strength) and (2) 34.5-m Ice Sprint = 6.495 − (0.134 × Relative Non-Dominant Peak Force) + (0.001 × Absolute Non-Dominant Peak Force) − (0.001 × Absolute Bilateral Strength). Conclusions: Our results show that BL strength and power deficits do not correlate with on-ice sprint performance in hockey players. However, there are correlations between strength/power variables and ice sprints. The results also show a difference between BL deficits in strength vs. power, as all subjects had BL power deficits; where as some subjects had BL strength deficits and others BL strength facilitations. Finally, prediction equations derived from regression analysis suggest that while BL deficit was not predictive, attributes related to both BL and UL strength and power do play a role in predicting ice sprint performance in this population. As BL deficit and facilitation are trainable, underlying mechanisms causing these differences as well as optimal levels of BL vs. UL strength and power to maximize ice hockey performance should be investigated. Practical Applications: Coaches who desire to improve sprinting performance in Ice Hockey should consider the inclusion of both UL and BL training for the improvement of both strength and power.
Friday, July 10, 2015, 9:15 AM–9:30 AM
A Comparison of the Potentiation Effects Following Ballistic and Non-ballistic Concentric-Only Half-Squats
T. Suchomel,1 K. Sato,1 B. DeWeese,1 W. Ebben,2 and M. Stone1
1East Tennessee State University; and 2Lakeland College
Strength and conditioning practitioners often seek training modalities that will produce superior results in training and competition. Postactivation potentiation has received much attention as a training modality and thus, an abundance of potentiation complexes have been designed and investigated. Despite the number of potentiation complexes that have been examined in previous studies, a paucity of research has compared the potentiation effects of the same exercise performed in a ballistic or non-ballistic manner. Purpose: The purpose of this study was to examine and compare the acute effects of ballistic and non-ballistic concentric-only half-squats (COHS) on squat jump performance. Methods: Fifteen resistance-trained men performed squat jumps before and 2 minutes following either a control protocol consisting of a dynamic warm-up or 1 of 2 potentiation protocols that included performing 2 ballistic or non-ballistic COHS at 90% of their 1RM COHS. Jump height (JH), peak power (PP), and allometrically-scaled peak power (PPa; W·kg−0.67) were compared using a series of 3 × 2 repeated measures ANOVAs. In addition, partial factorial ANOVAs were used to investigate statistically significant interaction effects. The relationships between JH potentiation during the ballistic and non-ballistic potentiation conditions and the subjects' relative back squat and COHS strength (kilogram per kilogram) were evaluated using Pearson's zero order, product-moment correlation coefficients. Results: Statistically significant condition × time interaction effects existed for JH (p = 0.037), PP (p = 0.041), and PPa (p = 0.031). Post hoc interaction-contrast analyses revealed that the ballistic condition produced statistically greater JH (p = 0.017 and p = 0.036), PP (p = 0.031 and p = 0.026), and PPa (p = 0.024 and p = 0.023) than the control and non-ballistic conditions, respectively. Large statistically significant relationships existed between the JH potentiation response and the subject's relative back squat strength (r = 0.520, p = 0.047) and relative COHS strength (r = 0.569, p = 0.027) during the ballistic condition. In addition, a large statistically significant relationship existed between JH potentiation response and the subject's relative back squat strength (r = 0.633, p = 0.011), while the moderate relationship with the subject's relative COHS strength trended toward significance (r = 0.483, p = 0.068) during the non-ballistic condition. Conclusions: Ballistic COHS may produce superior acute potentiation effects with regard to squat jump JH, PP, and PPa compared to non-ballistic COHS performed at the same absolute loads and a control condition. There were no differences in the potentiation effects between the non-ballistic potentiation condition and the control condition for any of the examined variables. The improvements in performance following the ballistic and non-ballistic potentiation protocols were strongly correlated with the relative strength of the subjects. Practical Applications: It is suggested that COHS performed in training should be performed in a ballistic manner to achieve the greatest training stimulus. If practitioners elect to use ballistic COHS in potentiation complexes, it is suggested that the complexes should be incorporated into a strength-power and/or explosive speed training block. Greater magnitudes of potentiation may be achieved by increasing the relative strength of the individuals using the potentiation complexes in training.
Friday, July 10, 2015, 9:30 AM–9:45 AM
Comparison of Force- and Power-Time Curve Characteristics During Jumping Between Strength Matched Male vs. Female Basketball Players
L. Carson,1 C. Goodman,2 C. Capps,1 J. Genbrands,1 and J. McBride1
1Appalachian State University; and 2Edith Cowan University
Differences in countermovement jump force- and power-time curves have been previously reported between males and females. Maximal squat strength has been found to influence jump performance as well. Purpose: The purpose of the this investigation was to isolate the possible influencing factors on jumping performance related to sex differences independent of the obvious differences in strength between males and females. Methods: An original subject pool of 8 men and 13 female DI basketball players were tested for maximal squat strength (S1RM) and countermovement jump (CMJ) performance. The 8 strongest females (FB), based on S1RM to body mass ratio (S1RMrat), were strength matched with a corresponding male subject (MB) with a difference of no more than 10% (FB S1RMrat = 1.35 ± 0.17, MB S1RMrat = 1.49 ± 0.20). This resulted in 8 MB (age: 20.6 ± 1.41 years; height: 188.3 ± 9.71 cm; weight: 95.9 ± 14.6 kg) and 8 FB (age: 19 ± 1.03 years; height: 176.8 ± 9.16 cm; body mass: 74.5 ± 6.5 kg) with no significant difference in S1RMrat. Maximal squat testing (S1RM) was performed by standardized procedures previously published and CMJ's were performed on a force plate. Forward dynamics were used to calculate velocity- and displacement-time curves for the CMJs. Force- and velocity-time curves were multiplied to generate power-time curves. Peak force (PF), rate of force development (RFD), time in the eccentric phase (Tecc), time spent in the concentric phase (Tconc), impulse in the concentric phase (IMP), peak power (PP), rate of power development (RPD), work in the concentric phase (Work), and jump height (JH) were analyzed from individual subject force- and power-time curves for the jumps. Peak force (PFrel), peak power (PPrel), impulse (IMPrel), and work (Workrel) relative to body mass were also calculated. Average force- and power-time curves for all male and female subjects combined respectively were also analyzed and presented in both absolute and relative terms. Results: PF (MB = 1,430 ± 280 N, FB = 1,088 ± 253 N), IMP (MB = 571 ± 96 N·s, FB = 455 ± 128 N·s), PP (MB = 6,175 ± 1,345 W, FB = 4,028 ± 950 W) and JH (MB = 0.60 ± 0.07 m, FB = 0.45 ± 0.07 m) was significantly greater in MB in comparison to FB (p ≤ 0.05). However, no significant differences existed in PFrel, RFD, Tecc, Tconc, RPD, Work, IMPrel or Workrel between MB and FB. The only relative variable that was significantly different between MB and FB was PPrel. Average force-time curves supported these findings in that while absolute force-time curves indicated many significant differences between MB and FB, force-time curves expressed relative to body mass showed no significant differences. Both absolute and relative average power-time curves showed significant difference between MB and FB. Conclusions: The data from this investigation indicates that differences in jumping ability between MB and FB are much less prevalent when matching these groups for relative maximal squat strength (S1RM). Meaning that sex differences, outside of the obvious differences in absolute and relative strength, between MB and FB may not play a large role in determining jumping performance. Practical Applications: Although there are some inherent sex differences in jumping ability, this study has provided data to indicate that by significantly increasing maximal squat strength in female athletes could improve their jumping performance and possibly approach performances similar to their male counterparts.
Friday, July 10, 2015, 9:45 AM–10:00 AM
Repeated Countermovements Show Increased Performance but Similar Muscle Activity Compared to a Single Countermovement During a Maximal Hop
D. Lidstone, J. McBride, Z. Howell, M. Moore, and H. van Werkhoven
Appalachian State University
Many previous studies have investigated conditions that optimize stretch-shortening cycle (SSC) performance in continuous hopping. Recently it has been shown that repeated countermovements prior to an isolated maximal-height hop improves performance in this task. It is possible that repeated countermovements accentuate the mechanisms by which SSC function is enhanced, which may be reflected in changes in muscle activity. Purpose: The primary purpose of this investigation was to determine whether (a) a repeated countermovement strategy (rCM) increases performance compared to a single countermovement strategy (sCM) in an isolated maximal-height hop, and (b) whether differences in muscle activation in the gastrocnemius muscle could explain differences in performance. Methods: Eight male subjects (age: 24 ± 2 years; height: 174 ± 5 cm; weight: 79 ± 9 kg) were fitted with knee immobilizers on both knees to ensure isolated movement at the ankle joint. EMG electrodes were placed on both the right medial and lateral gastrocnemius (mGAS and lGAS). Each subject performed 9 sCM hops and 9 rCM hops for maximal height at various frequencies and the best hop for each condition (sCM or rCM) was selected for further analysis. For the sCM hops, subjects were instructed to lift their heels before producing a single countermovement before toe-off. For rCM hops, subjects were instructed to lift their heels and produce 3 countermovements before toe-off. The order of trials (sCM or rCM) was randomized. Hop height was calculated using flight time derived from force plate data. Integrated EMG was calculated for the last countermovement before toe-off for each hopping condition for both medial gastrocnemius (iEMG-mGAS) and lateral gastrocnemius (iEMG-lGAS). Results: Hop height during rCM were significantly higher in comparison to sCM (rCM = 6.61 cm, sCM = 5.08 cm; p ≤ 0.05). There were no significant differences in iEMG-mGAS (rCM = 27.39 mV·s−1, sCM = 33.28 mV·s−1; p = 0.16) or iEMG-lGAS (rCM = 26.00 mV·s−1, sCM = 27.39 mV·s−1; p = 0.44) across the 2 conditions. Conclusions: Repeated countermovements prior to a hop significantly enhanced hop height compared to single countermovement. This increased performance did not coincide with increased gastrocnemius muscle activation. Performing repeated countermovements might allow the muscle to move to a more optimal muscle length that enhances the force production capability of the muscle independent of muscle activity. Practical Applications: Understanding the underlying mechanisms associated with improved performance in SSC movements are important for developing training protocols for the enhancement of SSC athletic activities such as hopping, jumping and running.
Friday, July 10, 2015, 10:00 AM–10:15 AM
Relationship Between Countermovement Jump Performance and Measures of Dynamic Strength in Division I Football Players
J. Mehlhorn,1 C. Goodman,2 R. Battista,1 C. Looney,1 C. Capps,1 and J. McBride1
1Appalachian State University; and 2Edith Cowan University
Previous research has investigated dynamic strength measures such as the squat and power clean and their relationships to jump performance; however, many of these studies have suffered from small sample sizes or have utilized recreational or sub-elite athletes. Thus, it is important to examine the relationship between exercises commonly employed as dynamic strength measures and movements performed during competition in a large number of high level athletes. Purpose: The purpose of this study was to examine the relationship between countermovement jump performance and measures of dynamic strength in elite football players. Methods: Seventy-six NCAA Division I football players (age, 19.8 ± 2.1 years; height 183.7 ± 6.3 cm; mass, 100.9 ± 19.5 kg; body fat percentage, 17.1 ± 7.1%) were assessed for maximal dynamic strength and countermovement jump performance in 2 separate sessions separated by several days. In the first testing session, subjects warmed up and then performed a 1 repetition maximum of the squat and power clean exercises. One repetition maximum values for the squat (S1RMr) and the power clean (PC1RMr) were then divided by body mass to obtain relative maximums. In the second testing session, subjects warmed up on a stationary bicycle and then performed 3 countermovement jumps on a force plate. Subjects were instructed to keep their hands on their hips and to jump with maximal effort. The last of the 3 jumps was analyzed for jump height (JH), relative peak power (PPr), and relative peak force (PFr). Subjects were also tested for height, weight, and body composition during the second testing session. Results: Mean values for the S1RMr and PC1RMr were 1.80 ± 0.38 and 1.21 ± 0.20 respectively. During the countermovement jump mean values were as follows: JH = 0.43 ± 0.07 cm; PPr = 56.4 ± 7.1 W·kg−1; PFr = 25.1 ± 3.1 N·kg−1. Significant (p ≤ 0.05) correlations were found between JH and PC1RMr (r = 0.71), PPr and PC1RMr (r = 0.65), PFr and PC1RMr (r = 0.57), JH and S1RMr (r = 0.59), PPr and S1RMr (r = 0.56), and PFr and S1RMr (r = 0.55). Conclusions: The results of this study show that there are moderate to strong correlations for dynamic strength assessments and all measures of countermovement jump performance. Additionally, the power clean was slightly superior to the squat in predicting countermovement jump performance. Practical Applications: The relationship between dynamic strength measures and countermovement jump performance suggest that athletes that possess a greater amount of relative dynamic strength tend to perform better in sport-specific movements such as the countermovement jump. Performances in both the squat and power clean exercises showed moderate to strong correlations with jump performance further validating the use of these exercises when attempting to improve powerful bodyweight movements. Countermovement jumps, being a high power activity, serve as a good representation of movements required in sport. Strength and conditioning professionals should therefore attempt to increase the relative strength of their athletes in order to improve on-field performance capabilities.
Friday, July 10, 2015, 10:15 AM–10:30 AM
Effects of the Innervation Zone on Electromyographic Time and Frequency Domain Parameters During a Fatiguing Isometric Muscle Action
C. Smith,1 T. Housh,1 T. Herda,2 J. Zuniga,3 E. Ryan,4 C. Camic,5 H. Bergstrom,6 D. Smith,7 J. Weir,2 J. Cramer,1 K. Cochrane,1 E. Hill,1 N. Jenkins,1 R. Schmidt,1 and G. Johnson1
1University of Nebraska-Lincoln; 2University of Kansas; 3Creighton University; 4University of North Carolina-Chapel Hill; 5University of Wisconsin–La Crosse; 6University of Kentucky; and 7Oklahoma State University
Purpose: The purpose of this study was to examine the effects of electrode location on electromyographic (EMG) amplitude (AMP) and frequency (MPF) patterns of responses during sustained submaximal isometric muscle actions of the leg extensors. Methods: Seven men and 2 women (mean ± SD age = 22.6 ± 2.4 years; body mass = 82.2 ± 14.8 kg; height = 181.3 ± 10.5 cm) performed submaximal and maximal voluntary isometric contractions (MVIC) of the dominant leg extensors at a knee joint angle of 120°. A linear electrode array was used to determine the location of the innervation zone (IZ) and the pennation angle of the muscle fibers of the vastus medialis (VM). Bipolar surface electrode arrangements (10 mm interelectrode distance) were used to record EMG signals from the VM over the IZ as well as 30, 20, and 10 mm proximal and distal to the IZ. The subjects performed 2, 6 seconds, MVIC with a 2 minutes rest between trials, followed by a sustained isometric muscle action to exhaustion at 50% MVIC. EMG AMP and MPF were calculated from 500 milliseconds epochs for each electrode arrangement every 5% of the time to exhaustion to determine the patterns of responses during the fatiguing task. Linear regression was used to determine the slope coefficients for the mean EMG AMP and MPF (normalized to the value at MVIC) vs. time (normalized to the time to exhaustion) relationships for each electrode arrangement. Results: For all 7 electrode arrangements (over, proximal, and distal to the IZ) EMG AMP increased and EMG MPF decreased across time during the sustained isometric muscle action. Furthermore, there were no differences (p > 0.05) among slope coefficients for the EMG AMP (0.0104–0.0347) or MPF (−0.0081 to −0.0154) vs. time relationships for any of the 7 electrode arrangements. Conclusions: The current findings indicated that the EMG time (EMG AMP) and frequency (MPF) domain parameters during a sustained submaximal isometric muscle action of the leg extensors demonstrated the characteristic patterns associated with fatigue. In addition, all electrode arrangements demonstrated the same rate of fatigue-induced changes for the EMG AMP and MPF vs. time relationships. These findings indicated that the IZ did not affect the EMG AMP and MPF vs. time responses to fatigue during submaximal isometric muscle actions. Practical Applications: The findings of the present study have implications for electrode placement guidelines when examining EMG patterns of responses during fatiguing muscle actions. Specifically during fatiguing isometric muscle actions, EMG signals can be measured over or away from the IZ. Thus, regardless of electrode placements relative to the IZ, the rate of fatigue-induced changes in EMG parameters from the VM are the same throughout a fatiguing, isometric muscle actions of the leg extensors.
Friday, July 10, 2015, 10:30 AM–10:45 AM
Competing in a Multistage Ultra-endurance Triathlon Reduces Body Mass and Fat Mass and May Increase Fluid Retention and Insulin Resistance
D. Baur,1 C. Bach,1 W. Hyder,2 and M. Ormsbee1
1Institute of Sports Sciences and Medicine, Florida State University; and 2Florida State University
Ultra-endurance events (≥6 hours of endurance performance) have seen a surge in popularity in recent years. Due to the nature of these events, more research is warranted to determine the physiological effects and potentials dangers inherent to them. Purpose: The primary purpose of this investigation was to determine the effects of participation in a 3-day multistage ultra-endurance triathlon (stage 1 = 10 km swim, 144.8 km bike; stage 2 = 275.8 km bike; stage 3 = 84.4 km run) on body mass and composition, hydration status, and blood glucose. Methods: Eighteen triathletes (mean ± SD; age = 41 ± 7.5; height = 175 ± 9 cm; weight = 73.5 ± 9.8 kg; fat mass = 7.6 ± 6 kg; fat-free mass = 66.0 ± 10.4 kg; total body water = 48.3 ± 7.6 kg; blood pressure = 121/68 ± 11/12; male n = 14, female n = 4) participated in body composition analysis prior to and immediately post-race. In subsets of 9 (male n = 6; female n = 3) and 7 (male n = 6; female n = 1), respectively, we were able to examine hydration status pre- and post-race and blood glucose before each stage of the race. Body mass and composition analysis was performed via a bioelectrical impedance (BIA) scale. Hydration status was measured via urine specific gravity. Blood glucose values were determined via fingerstick and a handheld glucose monitoring device. All measurements were done within ∼30 minutes pre- and post-race/stage. Results: From pre-to post-race, body mass and fat mass were reduced by 2.5% (p = 0.005) and 20.6% (p < 0.001), respectively. Fat-free mass (p = 0.421) and total body water (p = 0.414) did not change. Urine specific gravity (p = 0.012) increased by 1.2% indicating increased urine osmolality. Pre-stage blood glucose values increased between stages 1 and 2 (78.7–89.6 mg·dL−1; p = 0.002) and 2 and 3 (89.6–117.4 mg·dL−1; p = 0.01). In total, pre-stage blood glucose increased 49.2% between stages 1 and 3 (p = 0.002). Conclusions: Participation in a multistage ultra-endurance triathlon results in dramatic changes in body composition despite limited changes in body mass. Importantly, body mass and/or fat-free mass changes may be masked by potentially increased fluid retention as BIA estimates fat free mass via total body water estimation. Insulin resistance seems to develop over the course of the race possibly indicating muscle-damage-induced alterations in muscle glucose uptake and/or insulin signaling. Practical Applications: As more people are participating in ultra-endurance events worldwide, careful monitoring of body composition and metabolism is necessary to maintain endurance performance and health. In a multistage 3-day race, body mass changes alone may underestimate reductions in fat and lean mass due to enhanced fluid retention. Additionally, novel nutrition and/or recovery strategies may be warranted to maintain blood glucose control. The health impact over the course of a lengthy ultra-endurance career remains to be investigated.
Friday, July 10, 2015, 10:45 AM–11:00 AM
Core Stability Measures Predict Functional Movement Screen Scores
L. Kelleher,1 T. Beach,2 A. Johnson,1 and J. Dickey1
1University of Western Ontario; and 2University of Toronto
Purpose: The Functional Movement Screen (FMS) is used to evaluate key movement patterns, functional symmetry, and identify individuals that are at elevated risk of injury. The purpose of this study was to assess whether FMS scores can be predicted by measuring core stability or Y-Balance Test (YBT) reach distances. Methods: Sixty subjects (m = 30, f = 30; age = 28.3 ± 9.5; BMI = 24.1 ± 3.03) performed the 10 tasks (7 movements and 3 clearing tests) of the standardized FMS protocol, followed by the YBT, and bilateral side planks held until failure. The YBT protocol in this study comprised 4 bilateral practice trials in each reach direction—anterior, posterolateral, posteromedial—followed by a rest break. Three trials were then recorded bilaterally for each reach direction. The side plank position was supported with the forearm, the knees extended and the upper foot placed in front of the lower foot. The YBT reach distances were normalized to leg length and averaged between sides and trials. We completed a direct-entry regression, with FMS as the criterion variable, and anterior, posterolateral, posteromedial, and best plank as predictors. Results: There was an overall relationship between the independent variables and FMS (R2adj = 0.20, F (4,55) = 4.76, p = 0.002). The only statistically significant individual predictor of FMS was best plank (t = 2.76, p = 0.008). Conclusions: Maximally-held side planks predict FMS performance, suggesting that core stability is an important factor in “functional movement.” Although YBT reach distances are predictive of FMS scores when evaluated independently, they are not predictive of FMS scores when the best plank is included in the analysis. Further research on the relationship between global movement qualities and core stability should be undertaken to inform future training and rehabilitation strategies. Practical Applications: Several studies have shown that the FMS predicts increased injury risk during sports. This study has demonstrated that increased core stability is related to FMS score. If this relationship is causal, then core stability training could improve functional movement, which in turn may decrease susceptibility to injury derived from faulty movement patterns.
Friday, July 10, 2015, 11:00 AM–11:15 AM
Stronger Athletes Produce a Faster Agility Performance Through Greater Muscle Activation
T. Spiteri,1 R. Newton,2 N. Hart,3 J. Sheppard,4 and S. Nimphius5
1The University of Notre Dame Australia; 2Centre for Exercise and Sport Science Research, Edith Cowan University; 3Heath and Wellness Institute Edith Cowan University; 4Surfing Australia; and 5Edith Cowan University
Agility requires the effective utilization of strength to rapidly decelerate and reaccelerate in the new direction. While increased strength results from both nervous system and body compositional changes, the functional relevance of these variables to produce a faster agility performance, has yet to be examined. Purpose: To investigate differences in neural (magnitude of muscle activity) and body composition (cross-sectional area [CSA], lean, and fat mass) during an agility task between stronger and weaker athletes. Methods: Twelve elite female basketball athletes with 3 or more years experience at the national level were separated into stronger (n = 6) and weaker (n = 6) groups based upon their average relative strength capacity. Relative strength was calculated from the combined average of a 1-RM back squat, maximal eccentric and concentric only back squat and an isometric mid-thigh pull (stronger: age = 23.6 ± 2.9 years, height = 75.58 ± 7.0 cm, body mass = 68.52 ± 5.0 kg; weaker: age = 24.6 ± 2.2 years, height = 172.8 ± 6.4 cm, body mass = 69.9 ± 6.8 kg). Quadriceps muscle CSA was assessed by ultrasound and lean, fat and total mass distribution of the lower body was determined by dual-energy x-ray absorptiometry. Average relative muscle activity of the rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus was measured across stance phase of a 45° agility test responding to a basketball specific video stimulus. Results: Significant differences in all strength measures were observed between groups (Table 1). While no significant differences were observed in CSA (p = 0.39–0.72, ES = 0.26–0.66), relative lean mass (p = 0.25, ES = 0.72), fat mass (p = 0.25, ES = 0.67), nor total mass (p = 0.61, ES = 0.22). Significant differences between stronger and weaker groups in rectus femoris (p = 0.02, ES = 2.68), vastus lateralis (p = 0.03, ES = 2.54) and biceps femoris (p = 0.03, ES = 1.73) muscle activity was observed. Additionally, stronger subjects produced a significantly faster agility performance compared to weaker subjects (approach speed [s]: stronger = 1.67 ± 0.23, weaker = 2.04 ± 0.23; total time [s]: stronger = 3.57 ± 0.29, weaker = 3.93 ± 0.31, p = 0.04–0.05, ES = 1.27–1.89). Conclusions: While no differences were observed in body composition, the stronger group demonstrated significantly greater muscle activity across the stance phase that likely contributed to the significantly faster agility performance. These finding suggests that even in the absence of body compositional differences between stronger and weaker groups, there was an advantageous use of neural mechanisms (muscle activity) that may have be a characteristic of greater relative strength. Practical Applications: While research has typically demonstrated only small relationship between strength and agility, the underpinning neural adaptations displayed by stronger individuals is likely to improve transfer of neural adaptions to performance during dynamic bodyweight supported movements, such as agility.
Friday, July 10, 2015, 11:15 AM–11:30 AM
The Influence of Type I Myosin Heavy Chain Expression on Motor Unit Control Properties During a Submaximal Isometric Contraction
M. Trevino, E. Mosier, P. Gallagher, A. Fry, and T. Herda
University of Kansas
Purpose: The purpose of this study was to examine the influence of percent (%) type I myosin heavy chain (MHC) isoform expression on the y-intercept and slope values from the motor unit (MU) recruitment (REC) vs. mean firing rate (MFR) and MU REC vs. derecruitment (DEREC) relationships of the vastus lateralis (VL) during a 70% maximal voluntary contraction (MVC). Methods: Eight healthy men (age = 21.63 ± 2.39 years, body mass = 82.76 ± 10.30 kg) and 6 healthy women (age = 19.67 ± 1.37 years, body mass = 58.37 ± 7.97 kg) volunteered for this investigation. An electromyography (EMG) sensor was placed over the VL. Each participant performed 3 isometric MVCs of the leg extensors on an isokinetic dynamometer followed by an isometric trapezoid muscle action at 70% MVC calculated from the highest MVC. For the isometric trapezoid muscle action, the force was increased at a rate of 10% MVC per second to the deserved force level for 12 seconds followed by a decrease of 10% MVC per second to baseline. Decomposition techniques were applied to the EMG signals to extract action potentials and firing events of single MUs. The REC and DEREC thresholds and MFRs were calculated for each MU. Only MUs that were decomposed with accuracies >90% were included for analysis and linear regressions were performed to determine the slopes and y-intercepts of the REC vs. MFR and REC vs. DEREC relationships. After testing, subjects gave a muscle biopsy of the VL. The % type I MHC isoform expression for each subject was determined by SDS-PAGE. Pearson product-moment correlations were used to determine the relationship between % type I MHC isoform expression with the slope and y-intercept values from the REC vs. MFR and REC vs. DEREC relationships. Alpha was set at 0.05. Results: Pearson's product moment correlations were not significant when comparing % type I MHC isoform expression to the slope (p = 0.343, r = 0.274) and the y-intercept (p = 0.472, r = −0.210) values from the REC vs. MFR relationships and slope (p = 0.675, r = −0.123) and y-intercept (p = 0.588. r = 0.159) values from the REC vs. DEREC relationships. Conclusions: The slopes and y-intercept values from the REC vs. MFR and REC vs. DEREC relationships were not significantly correlated with % type I MHC expression. Practical Applications: MU behavior is reported to be influenced by the physical properties of the MU, however, the correlation analyses in the present study did not find a relationship among MHC expression and MU behavior.
Friday Abstract Poster Presentations—Session A
Friday, July 10, 2015, 11:30 AM–1:00 PM
The Relationship Between Physical Fitness Variables, Body Mass Index, and Predicted Body Fat Percentage in Physically Active Young Adults
E. Enquist,1 M. Richardson,1 M. Esco,2 A. Lynd,1 R. Snarr,1 A. Hallmark,1 K. Allen,1 and A. Fava1
1University of Alabama; and 2The University of Alabama
Purpose: The purpose of this study was to determine the independent relationships between selected markers of physical fitness, BMI and predicted BF% in physically active college-age adults (≥150 minutes moderate intensity exercise per week). Methods: Twenty (7 men and 13 women) college-age adults (age 21.0 ± 1.9 years; height 167.9 ± 10.7 cm; weight 69.8 ± 16.3 kg) volunteered to participate in this study. The 3-site skinfold technique was used to estimate BF%. BMI was determined as weight divided by height squared (kg·m−2). A maximal graded treadmill exercise test was performed to determine maximal oxygen uptake (V[Combining Dot Above]O2max). Vertical jump performance (VJ) was measured with a vertical measuring device. The 5-10-5 pro agility test was used to measure agility. The push-ups (PU) to failure test was performed for muscular endurance. Results: The mean ± SD for BF% = 20.9 ± 5.9%, BMI = 24.5 ± 3.8 kg·m−2, V[Combining Dot Above]O2max = 43.1 ± 6.9 ml·kg−1·min−1, VJ = 18.2 ± 4.6 in, 5-10-5 = 5.4 ± 0.4 seconds, and PU = 24.2 ± 15.1 reps. The fitness variables provided the following partial correlation coefficient (r) values to BF%, when controlling for BMI: r = −0.85, p < 0.001 for V[Combining Dot Above]O2max; r = −0.60, p = 0.006 for VJ; r = 0.48, p = 0.038 for agility; r = −0.85, p < 0.001 for PU. The fitness variables provided the following independent correlation coefficient (r) values to BMI, when controlling for BF%: r = −0.132, p = 0.590 for V[Combining Dot Above]O2max; r = 0.54, p = 0.016 for VJ; r = −0.261, p = 0.280 for agility; r = 0.57, p < 0.01 for PU. The correlation between BMI and BF% was r = 0.08, p = 0.746. Conclusions: BF% held moderate to large significant and negative independent correlations to the physical fitness variables. However, BMI held non-significant (V[Combining Dot Above]O2max and agility,) or moderately significant and positive (VJ, PU) independent correlations to the performance variables. In addition, BMI and predicted BF% were unrelated in the present study. Practical Applications: These findings strengthen the argument that performance on physical fitness tests is negatively influenced by BF%, but not BMI. Coaches and trainers should include BF% testing in combination with physical fitness tests as they have a significant relationship with active populations.
The Correlation Between Anthropometric Measures on Bone Mineral Density and Bone Mineral Content in Division One Women Athletes
S. Turner,1 S. Jenke,1 A. Jagim,2 M. Jones,3 and J. Oliver1
1Texas Christian University; 2University of Wisconsin–La Crosse; and 3George Mason University
An athlete's body composition is of particular importance to sports performance. However, low fat mass in women athletes is a characteristic associated with the onset of the female athlete triad, a condition characterized by disordered eating, amenorrhea, and osteoporosis. In addition to nutrition and hormone levels, information concerning an athlete's bone density may serve as a risk factor. Knowledge of bone density and bone mineral content requires expensive equipment not readily available to all athletes, while anthropometric measurements provide a simple and affordable method for determining body composition. Thus, it would be beneficial to understand the relationship between body composition and bone health in women athletes. Purpose: Therefore, the purpose of this study was to determine if a relationship exists between body composition and measures of bone health in division 1 women athletes across multiple sports. Methods: One hundred three (n = 103) women athletes (mean ± SD; 19.8 ± 1.2 years; 171.0 ± 8.0 cm; 68.4 ± 10.6 kg; 26.1 ± 4.4% fat) competing at a National Collegiate Association (NCAA) Division I institution volunteered for this study. Athletes were included from the following sports: basketball (n = 13), soccer (n = 25), swimming (n = 24), tennis (n = 8), track and field (n = 15), and volleyball (n = 18). Anthropometric measures were taken. At a single time point, dual energy x-ray absorptiometry (DEXA) scans were performed for determination of fat mass (FM), lean mass (LM), percent body fat (% BF), bone mineral density (BMD), and bone mineral content (BMC). Bivariate (Pearson) correlations were computed to determine relationship amongst variables of interest. Significance was set at p ≤ 0.05. Moderate correlations were defined as R-values of 0.41–0.70, and strong correlations were considered to be between 0.71 and 0.90. Results: A moderate correlation was observed between FM and LM (r = 0.636; p = 0.001). Further, though significant the correlation between % BF and LM was below moderate (r = 0.267; p = 0.006). FM was correlated with BMD (r = 0.343; p = 0.001), but this was below the cut off for moderate; while FM was moderately correlated with BMC (r = 0.554; p = 0.001). Similar observations were made with % BF BMD (r = 0.118; p = 0.236) and BMC (r = 0.281; p = 0.004), respectively. LM was moderately correlated with BMD (r = 0.552; p = 0.001) and strongly correlated with BMC (r = 0.767; p = 0.001). Conclusions: The results of this investigation suggest that LM may be a better predictor of bone health than FM or %BF, as evidenced by the correlation of LM between both BMD and BMC. FM was only moderately correlated with BMC while % BF was not correlated with any measures of bone health. Practical Applications: In athletic programs in which DEXA is unavailable, simple anthropometric measurements such as lean mass and fat mass, but not percent body fat, may be a tool for identifying women athletes at risk for osteoporosis, a characteristic of the athlete triad.
Individual vs. Generalized Lower Limit Cutoff Points When Estimating Heart Rate Deflection Point From Two Different Mathematical Models
K. Baker, D. Fukuda, M. La Monica, J. Stout, and J. Hoffman
University of Central Florida
When examining heart rate (HR) during graded exercise, there are often 2 breakpoints in linearity. The second breakpoint is indicative of HR deflection point (HRDP) which can be estimated using a variety of mathematical models. Purpose: To compare 2 different methods of determining HRDP with individual vs. generalized lower limit cutoff points used to account for the initial breakpoint from linearity on the HR-power curve. Methods: Ten recreationally trained males (mean ± SD; 24.0 ± 3.8 years; 77.0 ± 13.3 kg) performed a graded exercise test on a cycle ergometer. HR, respiratory gases (V[Combining Dot Above]O2, V[Combining Dot Above]CO2), and power output (POHRDP) were recorded. HRDP was determined using a bi-segmental linear regression method (2SEG) and a DMAX (maximal perpendicular distance) method with an exponential regression model. These methods were used to analyze values above cutoff values of both 140 b·min−1 and ventilatory threshold (VT) to determine HRDP (2SEGVT, 2SEG140, DMAXVT, and DMAX140, respectively). A 2-way (method × cutoff) ANOVA was used to analyze and examine the relationships between HRDP, POHRDP, and HRDP as a percentage of maximum HR (%HR), while correlations were used to examine the relationships between these values. Significance was set at α ≤ 0.10. Results: HRDP, POHRDP, and %HR values are presented in Table 1. No significant method × cutoff interactions were found between any of the selected variables. Significant main effects were shown for cutoff, with 140 b·min−1 yielding greater values, in HRDP (p = 0.061), POHRDP (p = 0.089), and %HR (p = 0.059). For POHRDP, there was a significant main effect for method (p = 0.069), with DMAX producing greater values than 2SEG. Only DMAXVT was significantly correlated with 2SEGVT (r = 0.655; p = 0.040) and DMAX140 (r = 0.763; p = 0.10). Conclusions: Both the calculation method and lower limit cutoff appear to impact the calculation of HRDP. The effects of these factors on HRDP estimation may be dependent on the variable of interest. Nonetheless, individual and generalized cutoff points should not be used interchangeably. Practical Applications: Coaches and practitioners must carefully evaluate the method used to estimate HRDP and should consider accounting for the lower cutoff threshold on an individual basis.
Perceptual and Physiological Responses During Cycle Ergometry at a Constant Perception of Effort
K. Cochrane,1 T. Housh,2 E. Hill,2 C. Smith,2 N. Jenkins,2 J. Cramer,2 G. Johnson,2 R. Schmidt,2 and C. Murphy2
1University of Nebraska, Lincoln-Human Performance Laboratory; and 2University of Nebraska-Lincoln
Purpose: The purposes of this study were to examine: (a) the patterns of responses for physiological, perceptual, and power output (PO) related variables during continuous cycle ergometry exercise at the constant rating of perceived exertion (RPE) within the heavy exercise intensity domain; and (b) the mechanisms that underlie the perception of effort during exercise in the heavy exercise intensity domain. Methods: Nine male subjects (mean ± SD age: 21.3 ± 2.1 years; body mass: 81.8 ± 6.9 kg; height: 179.9 ± 7.5 cm) performed an incremental cycling test to exhaustion for the determination of, gas exchange threshold (GET), and peak values for heart rate (HRpeak), breathing frequency (), respiratory exchange ratio (RERpeak), minute ventilation (peak), and power output (POpeak). On a separate day, subjects completed a 60 minutes ride starting at the PO and RPE corresponding to 15% above GET (GET + 15%). The subjects were asked to maintain the RPE corresponding to GET + 15% throughout the test. All values from the 60 minutes rides were normalized to a percentage of the corresponding peak value from the incremental test. Statistical analysis included polynomial regression analyses to determine the patterns of responses for the physiological, perceptual, and PO variables vs. time. Results: The 60 minutes rides at GET + 15% began at 73.5 ± 9.8% and ended at 60.8 ± 8.8%, which represented relative intensities within the heavy (above GET) and moderate (below GET) exercise intensity domains, respectively. There were, significant, negative, linear relationships for mean, normalized HR (r 2 = 0.63) and (r 2 = 0.67) vs. time during the 60 minutes rides. There were significant, negative, quadratic relationships for mean, normalized (R 2 = 0.94), RER (R 2 = 0.92), and PO (R 2 = 0.97) vs. time. In addition, there were no changes over time for mean, normalized or RPE. Conclusions: HR, RER, and tracked the decrease in PO across time. Only remained unchanged and tracked RPE across the 60 minutes rides. These findings suggested that afferent feedback from respiratory muscles associated with may have provided feedback to the motor cortex that contributed to the perception of effort during continuous cycle ergometry at a constant RPE that started above the demarcation of the moderate and heavy exercise intensity domains. In addition, HR, RER, and did not track RPE during the GET + 15% rides which indicated that feedback associated with the metabolic cost (), substrate utilization (RER), HR, and volume of expired air () did not mediate the perception of effort during constant RPE cycle ergometry. Practical Applications: The dissociations among, HR, RER, and RPE across time suggested that a decrease in the metabolic and cardiovascular cost of the exercise is required to maintain a constant perceptual intensity. Furthermore, exercise prescription using a perceptual intensity may provide a valuable option for athletes training for an extended period of time above the GET.
Influence of Home and Away Starts on In-Game Heart Rate Responses Among Professional Baseball Starting Pitchers
D. Cornell,1 R. Flees,1 R. Caplinger,2 J. Seligman,2 J. Paxson,2 N. Davis,2 and K. Ebersole1
1University of Wisconsin-Milwaukee; and 2Milwaukee Brewers Baseball Club
Previous research has primarily investigated the biomechanical aspects of pitching and the vast majority this research was conducted during simulated games or bullpen sessions. Thus, there is limited research examining the physiology of pitching during live competitive games. Furthermore, no prior study has examined the physiological differences in pitching between home and away games. As such, a better understanding of the physiological responses during live competition is needed in order to maximize training and performance outcomes among baseball starting pitchers. Purpose: The purpose of the current study was to examine the influence of game location (home or away) on in-game heart rate across innings pitched during live competitive games among professional baseball starting pitchers. Methods: In-game heart rate (HR) was recorded from 16 single-A professional baseball starting pitchers (mean ± SD, age = 22.1 ± 1.3 years; height = 187.9 ± 4.4 cm; weight = 90.5 ± 9.5 kg) using wireless physiological status monitors. In-game HR data was collected until either the pitcher was removed from the game, or when 6 innings of pitching was completed, for a total of 684 innings (home = 381; away = 303). HR data was analyzed after completing their respective warm-up pitches and before returning to the dugout. All analyzed HR data were then normalized to each pitcher's age-predicted maximal HR (220 – age) to create a percent HRmax ratio (%HRmax). A mixed-model split-plot repeated measures analysis of variance was used to examine the interaction effect of Inning × Game Location, as well as the main effects of Inning and Game Location on in-game %HRmax. An alpha of 0.05 determined statistical significance. Results: Group mean ± SD in-game %HRmax was 84.7% ± 4.3%. There was not a significant interaction effect for Inning × Game Location (F 5,522 = 1.474, p = 0.202), nor a significant main effect of Game Location (F 1,522 = 1.474, p = 0.202), on in-game %HRmax (home = 84.9 ± 4.0%; away = 84.5 ± 4.5%, respectively). However, a significant main effect of Inning on in-game %HRmax was identified (F 5,522 = 5.671, p < 0.001). Follow-up pairwise analyses indicated that the in-game %HRmax was significantly (p ≤ 0.05) higher during the first inning (86.6 ± 3.7%) than all other innings. Conclusions: These results suggest that the home or away location of the game does not influence in-game HR among baseball starting pitchers and that baseball starting pitching is a highly anaerobic task with a mean %HRmax of 84.7%. In addition, this %HRmax data suggests the intensity of baseball pitching is significantly higher during the first inning compared to innings 2–6. This elevated HR response in the first inning may represent a cardiovascular acclimation to the demands of pitching. It is possible that the pre-game warm-up intensity did not match the cardiovascular demands, and thus, the cardiovascular system over-responded. In addition, inning-dependent psychological factors (e.g., stress, anxiety, etc.) may have also contributed to the change in HR. Future research should examine the HR response of pre-game activities and possible psychological factors to better understand the cardiovascular responses to pitching. Practical Applications: Strength and conditioning professionals should prescribe exercises that emphasize anaerobic conditioning (e.g., interval training, sprints, etc.) when developing training programs for baseball starting pitchers.
Early Indication of Training Adaptation With Smartphone-Derived Heart Rate Variability in Collegiate Female Soccer Players
A. Flatt, and M. Esco
The University of Alabama
Cardiac-autonomic modulation as assessed by heart rate variability (HRV) is an objective physiological marker that coaches and sport scientists use to evaluate training status in athletes. Increases in HRV following longitudinal conditioning programs are typically associated with improved fitness. However, it is unclear if the evolution of HRV throughout training can be useful in providing early indications of individual adaptation. Purpose: The purpose of this study was to assess the relationship between changes in smartphone-derived HRV and resting heart rate (HR) within the first 3 weeks of a 5-week conditioning program with the eventual change in intermittent running performance assessed post-training. Methods: A collegiate female soccer team (n = 12; age = 22 ± 2.3 years; height = 165.05 ± 5.5 cm; weight = 60.6 ± 6.2 kg) participated in a 5 weeks conditioning program designed to improve intermittent running capacity. At week 0 and week 5, the athletes performed the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo). Throughout week 1 and week 3, athletes measured HRV and HR each morning after waking and elimination with a novel smartphone application. Change variables from week 1 to week 3 of the weekly mean and weekly coefficient of variation (CV) for log transformed root mean square of successive R-R intervals multiplied by 20 (ΔLn rMSSDmean and ΔLn rMSSDcv, respectively) and resting heart rate (ΔHRmean and ΔHRcv, respectively) were compared to changes in Yo-Yo performance (ΔYo-Yo). Results: Pre and post Yo-Yo values were 1,066.6 ± 243.8 m and 1,250 ± 247.2 m, respectively. Yo-Yo values significantly improved following the conditioning program (p ≤ 0.01, Cohen's d = −0.75). There were no mean differences between any of the Ln rMSSD or HR measures between weeks 1 and 3 (p = 0.05, Cohen's d ranged from −0.02 to −0.59), though individual responses varied. A large and significant negative correlation was found between ΔYo-Yo and ΔLn rMSSDcv (r = −0.74; p ≤ 0.01) and a large, non-significant correlation was found with ΔLn rMSSDmean (r = 0.50; p = 0.096). Moderate and non-significant relationships were found between ΔYo-Yo and ΔHRmean (r = −0.31; p = 0.324) and ΔHRcv (r = −0.363; p = 0.246). Conclusions: This study suggests that a decrease in day-to-day HRV fluctuation assessed via Ln rMSSDcv within the first 3 weeks of training is a favorable response, indicative of positive training adaptation. HRV demonstrated greater sensitivity than HR to performance adaptation. Practical Applications: The evolution of an athlete's HRV trend throughout training may provide coaches and sport scientists an early indication of individual training adaptation in female team-sport athletes. A reduction in the Ln rMSSDcv appears to be a favorable response, associated with greater eventual improvements in intermittent running capacity. Modification of training and lifestyle factors to maintain a favorable cardiac-autonomic profile throughout training may support physiological adaptations. Athletes characterized with a large increase in Ln rMSSDcv may be experiencing undue stress or fatigue and thus may benefit from training intervention. Collecting daily HRV data with a smartphone application utilizing ultra-short HRV measures appears useful for athlete monitoring.
Effects of a Multi-Stage Ultra-Endurance Triathlon on Body Composition and Glucose Control in a Type One Diabetic Athlete: A Case Study
C. Bach,1 D. Baur,1 W. Hyder,2 and M. Ormsbee1
1Institute of Sports Sciences and Medicine, Florida State University; and 2Florida State University
Research regarding the effects of ultra-endurance exercise on blood glucose (BG) control in type 1 diabetics (T1D) is limited. Moreover, T1D guidelines for dietary and insulin practices during ultra-endurance exercise have yet to be developed. Purpose: The primary purpose of this study was to investigate the dietary/insulin practices and physiological effects experienced by the first ever T1D finisher of a 3-day, multi-stage ultra-endurance triathlon consisting of a 10 km swim and 144.8 km bike (stage 1), a 275.8 km bike (stage 2), and a 84.4 km run (stage 3). Methods: BG was monitored via a continuous glucose monitoring device (Dexcom). The participant was fitted with the device the night prior to stage 1; it was removed 2 hour post-race. The participant was asked to maintain normal dietary and insulin patterns before, during and after competition each day. All dietary and insulin practices/adjustments were recorded in detail. Weight and body composition were measured via bioelectrical impedance. Results: The athlete (age, 35 years; height, 177.8 cm; weight, 73.2 kg) used a variety of practices to regulate his BG control throughout the course of the event. Insulin injections (both long- and short-acting) were taken prior to sleep and immediately upon waking each day. In-stage practice of BG control was regulated via dietary choices (e.g., high- or low-glycemic foods/gels/drinks) in order to achieve desired BG levels. Using “normal” glucose cutoffs of ≤80 and ≥130 mg·dL−1 for hypoglycemic and hyperglycemic, respectively, the athlete spent 73.0 (stage 1), 3.4 (stage 2) and 15.1% (stage 3) of during-race time in a hyperglycemic state and 0.0 (stage 1), 78.6 (stage 2), and 33.6% (stage 3) in a hypoglycemic state. Nocturnal glycemic levels showed the athlete spent 86.1 (night 1), 83.0 (night 2) and 84.8% (night 3) of sleep in a hyperglycemic state with 9.0 (night 1), 0.0 (night 2), and 0.0% (night 3) in a hypoglycemic state. From pre-to post-race, body weight increased (73.2–76.9 kg), fat mass increased (6.1–6.6 kg), fat free mass increased (67.2–70.4 kg), and total body water increased (49.2–51.6 kg). Conclusions: Based on limited data, participation in a 3-day, multi-stage ultra-endurance triathlon may lead to increases in body weight, fat mass, fat free mass, and total body water in T1D. While the underlying mechanisms for these unexpected changes remain undetermined, one potential reason may include fluid shifts resulting from glucose-dependent osmolality changes. Moreover, BG control seems to be increased during exercise but may be particularly influenced by the modality and/or order of exercise. In contrast with most research, this effect appears to be minimized for extended durations following this type of ultra-endurance exercise in a T1D athlete—possibly a result of exercise-induced muscle damage. More research is warranted to determine whether the insulin-independent mechanisms for BG uptake are altered during, and particularly post-, ultra-endurance exercise. Practical Applications: With proper monitoring and subsequent dietary/insulin actions to control BG status, it is possible for a person with T1D to complete a 3-day, multi-stage ultra-endurance triathlon; however there remains a lack of research/data regarding the safest and most efficacious practices for the athlete during such events—particularly considering the well-established safety concerns regarding endurance-related hypoglycemia.
The Effects of an Elevation Training Mask on V[Combining Dot Above]O2max of Male Reserve Officers' Training Corps Cadets
Texas A&M University-Corpus Christi
Purpose: The purpose of this study was to investigate the effects of an elevation training mask (ETM) on the V[Combining Dot Above]O2max of male Reserve Officers' Training Corps (ROTC) cadets. Methods: Fourteen male ROTC cadets (mean ± SD age = 20.00 ± 1.8 years, 174.35 ± 3.1 cm height, 76.75 ± 11.09 kg weight, 13.88 ± 4.62% body fat) participated in this study to investigate the effect of ETM training on V[Combining Dot Above]O2max. After completion of the pre-test (1.5 mile run for time), collection of all documentation, and cessation of the familiarization period, the test subjects were randomly placed in either the control (C) or experimental group (E), respectively. The training period, which included the standard ROTC physical fitness program, lasted 7 weeks with each subject participating in 36-minute sessions per week. The post-test (1.5 mile run for time), was administered 4 days after the final training session. Results: A t-test for independent samples was utilized to determine statistical significance (p ≤ 0.10) in V[Combining Dot Above]O2max scores between C vs. E (p = 0.34). Additionally, a t-test for dependent samples was calculated to compare pre-test and post-test scores for E (p = 0.08). Conclusions: The results of this study determined statistical significance between pre-test and post-test V[Combining Dot Above]O2max scores for E (p ≤ 0.10). Practical Applications: The results of this study indicate that ETM could be considered as a possible training tool to increase V[Combining Dot Above]O2max in ROTC populations. However, it should be noted that there is a particular amount of time in which an individual must be exposed to a hypoxic environment before any physiological adaptations leading to acclimatization is achieved. It is suggested that further research be conducted to investigate the increase in the frequency of exposure to an ETM, as well as an increase in the length of the training period.
Hamstrings: Quadriceps Ratio Is Affected by Years of Experience in American Collegiate Rugby Athletes Independent of Age and Body Weight
K. Beyer, D. Fukuda, A. Miramonti, E. Robinson, J. Stout, and J. Hoffman
University of Central Florida
The absolute measures of single muscle group strength and agonist-antagonist ratio of strength between the quadriceps and hamstrings can provide an assessment of joint function and stability. In the sport of rugby, as with most running-based team sports, lower body strength and stability are important for optimal performance and injury prevention. Purpose: To compare the hamstrings: quadriceps ratio between American collegiate male rugby athletes with at least 2 years of experience to those with less than 2 years of experience. Methods: Quadriceps and hamstrings strength was assessed in 24 American collegiate male rugby athletes via isokinetic dynamometer. Quadriceps strength was measured concentrically at 1.04 (QuadSLOW) and 3.14 (QuadFAST) radians/second. Hamstrings strength was measured concentrically and eccentrically at 1.04 (ConHamSLOW and EccHamSLOW, respectively) and 3.14 (ConHamFAST and EccHamFAST, respectively) radians/second. Eccentric hamstrings strength was used to calculate functional hamstrings:quadriceps ratio for each speed (EccH:QSLOW and EccH:QFAST, respectively). Concentric hamstrings strength was used to calculate conventional hamstrings:quadriceps ratio for each speed (ConH:QSLOW and ConH:QFAST, respectively). Gravity effect torque was measured at 30° of knee flexion and subsequently accounted for during testing. The athletes were then grouped based on their number of years of experience in the sport of rugby, with 14 having less than 2 years (n = 14; 19.79 ± 1.31 year; 1.77 ± 0.05 m; 78.55 ± 10.79 kg) of experience and 10 having at least 2 years of experience (n = 10; 20.70 ± 1.95 year; 1.79 ± 0.08 m; 86.81 ± 15.38 kg). Analysis of covariance (ANCOVA) was used to examine differences between the 2 groups while body weight and age served as the covariates. Significance was set at an alpha level of 0.05. Results: No significant differences were noted between groups for QuadSLOW (p = 0.281), QuadFAST (p = 0.208), ConHamSLOW (p = 0.525), ConHamFAST (p = 0.881), EccHamSLOW (p = 0.179), or EccHamFAST (p = 0.462). However, a significant difference was observed in EccH:QSLOW (F = 4.502, p = 0.047, η 2 = 0.184) between the 2 groups. The group with at least 2 years of experience had a higher EccH:QSLOW than the inexperienced group (0.94 ± 0.11 vs. 0.81 ± 0.16). There was no difference between groups for ConH:QSLOW (p = 0.072), ConH:QFAST (p = 0.361), or EccH:QFAST (p = 0.271). Conclusions: Despite no differences between groups in quadriceps or hamstring strength, there was a difference in EccH:QSLOW even when controlling for age and body weight. Also, a trend was observed for ConH:QSLOW (0.50 ± 0.07 vs. 0.45 ± 0.06; p < 0.10). It appears that rugby athletes with at least 2 years of rugby experience appear to have a greater hamstrings:quadriceps ratio, specifically at slower speeds of contraction. Practical Applications: American collegiate rugby coaches should assess not only absolute measures of single muscle group strength in the lower body, but also the agonist-antagonist ratio of strength. Inexperienced rugby athletes may not exhibit differences in single muscle groups compared to experienced athletes, but may possess a deficiency in functional hamstrings:quadriceps ratio. This could result in an increased susceptibility to knee injuries, specifically injuries to the anterior cruciate ligament, and decreased sport performance.
Physical Maturation of Pre-adolescent Boys and Girls During Performance Measures of Power and Agility
A. Drusch, E. Sobolewski, M. Stock, B. Thompson, Z. Kittley, S. Fehoko, J. Mota, and M. Lochbaum
Texas Tech University
Maturation and sex-specific characteristics play important roles in identifying physical performance capabilities, especially in pre-adolescents. Thus, identifying differences across age and sex for performance characteristics may be useful when developing exercise programs used in school and/or sport for achieving optimal physical fitness. Purpose: The purpose of this study was to examine age and sex differences during commonly used power and agility measurements in youth. Methods: All testing for this study occurred on a Saturday at the Texas Tech University Human Performance Laboratory. Upon arrival, 53 pre-adolescent (age range = 8–14 years) children had their body mass and stature measured. Peak and mean lower-body power (W) and velocity (m·s−1) measurements during a countermovement vertical jump were quantified using a linear velocity transducer, which was attached to the posterior side of a belt that was securely fastened to the subjects' waistline. Horizontal power was assessed via standing long jumps (cm). Upper-body power was measured via seated and overhead medicine ball throws (m). Seated medicine ball throws for maximal distance were performed with subjects seated against a wall with extended legs. Standing overhead medicine ball throws consisted of tossing the ball backwards overhead. Reactive agility was measured in seconds during a Y-shaped sprint through a triggered timing gate, followed by a 45° cut and 4.5 m sprint through the left or right finishing gates. All performance tests consisted of 2–3 maximal effort attempts. Following data collection, the subjects were dichotomized into groups based on age and sex, to either older boys (mean ± SD stature = 158.8 ± 11.6 cm, mass = 60.5 ± 22.3 kg, n = 16), younger boys (142.6 ± 7.1, 46.5 ± 11.6, n = 14), older girls (150.5 ± 8.0, 46.2 ± 12.0, n = 14), or younger girls (141.3 ± 7.3, 42.2 ± 12.5, n = 9). Older and younger children were classified as ages ≥11 and ≤10 years, respectively. Analyses of variance were performed to examine age × sex interactions. Results: For vertical jump performance, the older boys produced greater peak and mean power than the other 3 groups (p < 0.04), but no other differences were noted. There were also no differences for both peak and mean jumping velocity across age and sex. For horizontal power, there was no difference for sex; however, the older groups jumped further than the younger groups (p < 0.04). For both seated and standing medicine ball throw distance, older boys had greater upper-body power than any other group (p < 0.01), but no other differences were noted. Older boys and girls demonstrated faster agility times than the younger groups, but no sex-specific differences were noted. Conclusions: Our findings demonstrate that boys ≥11 years of age display significantly greater upper- and lower-body power output than younger boys and girls. In contrast, standing long jump distance demonstrated no age-related differences, which is suggestive of unique power-related attributes between vertical and horizontal measures of power. Agility performance appears to be affected by age more so than sex. Practical Applications: Strength and conditioning practitioners and physical educators should understand that both upper- and lower-body power are greatly influenced by maturation, particularly in boys. Training techniques to develop upper-body power in pre-adolescent girls seem particularly important.
The Association of Peak Force on a Portable Isometric Device With Age Among Older African American Females
L. Marcus,1 D. Bellar,1 G. Davis,1 and L. Judge2
1University of Louisiana at Lafayette; and 2Ball State University
Muscle function declines with advancing age. Therefore, it is important to have the ability to quickly assess muscle function in groups of older adults. Purpose: The purpose of the present investigation was to assess the association of age and peak force determined by a custom built, portable isometric mid thigh pull device. Methods: Thirty five older community dwelling African American females (mean ± SD: age = 65 ± 7 years, height = 162 ± 7 cm, weight = 78 ± 15 kg) participated in this study. The participants gave written informed consent, after which anthropometric data was collected and an isometric mid thigh pull test was performed. The isometric mid thigh pull test was performed on a portable custom built wooden platform, which allowed a load cell (iLoad Pro) to be secured between the feet of the participant. A light metal chain was attached to the load cell, which terminated in a handle composed of a solid steel bar. The participants were positioned to ensure that each had between 120–130° of knee flexion and a vertical posture in the trunk. The knee angle was assessed via a goniometer and the trunk was assessed via a contractor's 48 inch box level. The load cell data was captured via a computer package (LoadVue) at 150 Hz and peak force was extracted from the raw data. Results: A linear regression was used to compare the peak force values from the mid thigh pull assessment and the age of the participants. A modern statistical software package was used to perform the analysis. Conclusions: Among a group of community dwelling older African American females, isometric mid thigh pull performance as measured via a load cell on a portable platform is moderately associated with age. The device itself offers several advantages over field based assessments of strength. These include the short time to administer the assessment (only a few seconds) and the listed accuracy of the instruments used (0.25% of measurement). However, further study will be required with larger populations to determine the overall strength of the relationship of this data to variables associated with aging. Practical Applications: Maintenance of strength is important with advancing age. Therefore, it is important to have quick and accurate assessments of this functional capacity. The portable instrument developed for this investigation is promising in its ease of use and data collected, but further work is needed to determine its value as a measure in the study of aging.
Effects of Height and Leg Length on Palpation Accuracy after Completing Two Different Submaximal Three Minute Step Test Protocols
K. Huet,1 N. Harris,1 A. Bosak,2 and A. Kleitz1
1Armstrong State University; and 2Liberty University
Prior studies have evaluated the accuracy of participants palpating their carotid heart rate (HR) immediately following submaximal exercise. The Queen's College Step Test (QCST) is a submaximal aerobic capacity test where participants palpate their post-step test recovery HR (RHR) at the carotid artery in the traditional standing position. Post-exercise RHR has an important relationship with step tests which means accurate palpation of the RHR is important for the precise development of cardiovascular exercise programs. Despite a decent amount of step test research existing, there does not appear to be a study that examined the relationship between subject height and leg length with post-step test palpation accuracy after completing both the men's (MC) and women's (WC) QCST protocols. Potentially, a taller subject's RHR may be lower due to a possible lighter intensity since vertical distance traveled relative to the subject's body height might be less with the WC vs. the MC. Also, the slower QCST cadence between the women's test (88 b·min−1) and the men's test (96 b·min−1) could yield a lower RHR due to fewer total number of steps completed within the 3 minutes of stepping activity which may contribute to a more accurate palpation count. Purpose: The purpose of this study was to examine the influence of participant height and leg length on female participants' palpation accuracy after completing the women's and men's' QCST protocols. Methods: Thirty-two at least averagely fit female college students (22.84 ± 3.23 years, 167.90 ± 8.02 cm, 64.00 ± 7.62 kg, and BF %: 23.81 ± 6.66%) completed both the QCST MC and WC in a counterbalanced order with no more than 6 days between each test. Participants were connected to an EKG using the 5-lead system and first completed two 20-second familiarization trials of palpating the carotid artery. Participants then completed the 3 minutes QCST using a 41.3 cm step height. Upon completion of stepping activity, participants palpated their HR, while in a standing position, at the carotid artery site within 5 seconds and then counted their post-step test RHR for the next 15 seconds. Results: There were no significant differences or direct correlations between height and participants' post-WC palpation accuracy (r = −0.263, p = 0.073) or height and participants' post-MC palpation accuracy (r = −0.131, p = 0.238). No significant differences or direct correlations were found between leg length and participants' post-WC palpation accuracy (r = −0.260, p = 0.075) or leg length and participants' post-MC palpation accuracy (r = −0.072, p = 0.348). Conclusions: Although there was no statistical significance and a very weak correlation for palpation accuracy existed in relation to participants' height and leg length, the data suggest the participants had less of a weak relationship and were slightly more accurate with palpating their RHR following the QCST men's protocol vs. the women's protocol. Practical Applications: The study's results suggest that matching the correct protocol (MC vs. WC) to the subject's physical characteristics (i.e., height and/or leg length) may be necessary to improve their palpation accuracy rather than basing the chosen protocol on their specific gender. Future research may be required to assess the actual V[Combining Dot Above]O2max values vs. the submaximal V[Combining Dot Above]O2max estimated values from the QCST in relation to the subject's height, leg length, and completed MC and WC protocols.
Physiological Profile of Projected Field Starters and Non-starters in a Division I Female Soccer Team
S. Mock, F. Jalilvand, S. Stecyk, J. Crelling, J. Lockwood, and R. Lockie
California State University, Northridge
Soccer is a team sport in which players are often substituted for one another in both competition and training due to a variety of circumstances (e.g., tactical considerations, injury, player fatigue). Matches are played with 11 players per side, and the average Division I collegiate women's soccer team contains 27 players. If starting players and non-starting players have similar physiological capacities and physical abilities (e.g., repeat-sprint ability, multidirectional speed, lower body power), then players could be substituted for one another as dictated by match play, and a high level of play during training could be maintained. As such, it is important that all members of a team have similar physiological capacities and physical abilities. This requires further investigation in Division I female collegiate soccer. Purpose: To determine if there are differences in physiological characteristics across projected starting players and non-starting players on a Division I collegiate female soccer team. Methods: 25 female soccer players from a Division I team were recruited. During the non-traditional season, players were assessed using field tests for linear speed (0–5, 0–10, 0–30 meter sprint intervals); soccer-specific fitness (Yo-Yo Intermittent Recovery Test Level 1 [YYIRT1]); change-of-direction speed (pro-agility shuttle; 60-yard shuttle; Arrowhead); and vertical and standing broad jump performance. A one-way analysis of variance (p ≤ 0.05) was used to calculate any significant differences in physiological assessment results between starting and non-starting players. Effect sizes and percent change were calculated for select comparisons. Although data for goalkeepers was collected, they were not included in statistical analysis due to different physiological demands during match play. Results: There were no significant differences in any physiological characteristics between starting and non-starting players on this team. Most effects were low (0.01 < d < 0.45). However, there was a non-significant, moderate effect for the 30-m sprint time for starting and non-starting players (d = 0.63), as starting players had a 2% faster sprint time compared to non-starting players. Conclusions: Division I collegiate female soccer players on the same team exhibited similar physiological capabilities as measured by a variety of linear speed, change-of-direction speed, lower body power, and soccer-specific assessments. This could allow non-starting players to substitute for starting players during match play for tactical purposes or injuries and during training to ensure that a high level of play is maintained. There was a tendency for starting players to be faster during the 30-m sprint trial, which suggests that starting players have the ability to maintain a high running speed over a relatively longer effort. Practical Applications: Soccer coaches and sports performances coaches should ensure that an adequate level of physical fitness is achieved and maintained by all members of a Division I collegiate female soccer team, regardless of projected playing time.
Acute Effects of Self-Myofascial Release and Static Stretching on Shoulder Range of Motion and Performance in Athletes With Gird
R. Fairall, L. Cabell, R. Boergers, and F. Battaglia
Seton Hall University
Over the last decade, self-myofascial release has been commonly combined with static stretching during the pre-activity warm-up period to assist in improving range of motion, in theory, decreasing risk of injury. However, there has been limited research examining the acute effects of these combined interventions. Purpose: To examine the acute effects of (a) self-myofascial release (SMR), (b) static stretching (SS), and (c) the combination of self-myofascial release and static stretching (SMR + SS) on glenohumeral internal rotation range of motion (IR ROM) and markers of shoulder performance (i.e., glenohumeral external rotation isometric strength, motor unit recruitment, and throwing velocity) in male softball players with glenohumeral internal rotation deficit (GIRD). Methods: The sample consisted of 12 male amateur softball players (age: 36.92 ± 11.17 years; height: 177.42 ± 6.30 cm; mass: 87.58 ± 18.39 kg) who exhibited ≥20° less internal rotation range of motion (ROM) in the throwing shoulder compared to the non-throwing shoulder. All participants performed each of the 3 conditions of SMR (with a lacrosse ball on the infraspinatus), SS (sleeper and cross-body stretches), and SMR + SS on 3 separate sessions. Dependent variables of glenohumeral IR ROM (deg), glenohumeral external rotation isometric strength (N), motor unit recruitment using surface electromyography (EMG) of infraspinatus (agonist), pectoralis major (antagonist), and latissimus dorsi (antagonist) during isometric glenohumeral external rotation strength testing (% of MVC), and overhead throwing velocity (m·s−1) were measured pre- and post-intervention. Results: Glenohumeral IR ROM significantly increased in all 3 conditions of SMR (3.84° ± 1.42; p = 0.0001; d = 0.77), SS (8.58° ± 4.42; p = 0.0001; d = 1.40), and SMR + SS (10.15° ± 4.95; p = 0.0001; d = 1.62). The conditions of SS (p = 0.01; d = 1.19) and SMR (p = 0.001; d = 1.43) improved IR ROM significantly more than SMR alone. SMR + SS resulted in a slightly greater increase in IR ROM (1.57°) when compared to SS alone, but the difference was not statistically significant. None of the 3 conditions resulted in any significant decreases in glenohumeral external rotation isometric strength, motor unit recruitment, or throwing velocity. However, SMR + SS resulted in a significant increase in infraspinatus EMG magnitudes (7.52% ± 9.23; p = 0.02; d = 0.82) and decrease in pectoralis major (5.90% ± 7.98; p = 0.03; d = 0.62) and latissimus dorsi (11.88% ± 17.28; p = 0.04; d = 0.80) EMG magnitudes during glenohumeral external rotation isometric strength testing. Conclusions: According to the results, all 3 conditions significantly improved glenohumeral IR ROM, in theory decreasing risk of injury without negatively affecting performance (i.e., isometric strength, motor unit recruitment, and throwing velocity). SS and SMR + SS improved IR ROM significantly more than SMR alone, however, there was no significant difference in improvements in IR ROM between SS and SMR + SS. Practical Applications: If the athlete has a limited amount of time to perform a pre-activity warm-up period (i.e., 3–4 minutes), it is recommended to use just SS to improve IR ROM. However, if the athlete has more time available to warm up (i.e., 7–8 minutes), it is recommended to perform SMR + SS, which may result in an even greater increase in ROM and possible improvements in motor unit recruitment. Further research is warranted to determine any long-term effects of SMR and SMR + SS.
Effects of Static Stretching, Dynamic Stretching, and Foam Rolling on Flexibility, Power, Strength, and Speed of Female Athletes
T. Kong and B. Thompson
Springfield College, Springfield, Massachusetts
Static stretching and dynamic stretching are commonly used before exercises; foam rolling has become a prevalent type of warm-up technique used by professional athletes in recent years. Few studies exist regarding the comparison of static stretching, dynamic stretching, and foam rolling, to determine which warm-up condition is more effective in enhancing physical performance in athletes. Purpose: The purpose of this investigation was to compare the effects of static stretching, dynamic stretching, and foam rolling on flexibility, power, strength, and speed of female athletes. Methods: Fifteen National Collegiate Athletic Association (NCAA) Division III female soccer players (mean ± SD age = 19.27 ± 0.88 year) participated in this investigation, and completed the 3 testing sessions. Each participant performed a static stretching, dynamic stretching, or foam rolling in each session. After the warm-up condition the participants were assessed by the modified sit and reach test, countermovement vertical jump test, standing long jump test, 3-RM front squat test, and 20-m sprint test. Five separate one-way repeated measures ANOVAs were calculated to analyze the differences among the warm-up conditions in flexibility, power, strength, and speed performance. Results: The results indicated that dynamic stretching resulted in a significantly (p ≤ 0.05) greater performance in the countermovement vertical jump (mean = 20.09, SD = 2.60), standing long jump (mean = 72.60, SD = 6.87), and 20-m sprint (mean = 3.78, SD = 0.17) than static stretching ([mean = 18.54, SD = 2.49]; [mean = 71.30, SD = 7.54]; [mean = 3.87, SD = 0.19]). In terms of the countermovement vertical jump test, dynamic stretching also resulted in a significantly (p ≤ 0.05) greater performance than foam rolling (mean = 19.01, SD = 2.69). No significant (p > 0.05) differences among the 3 warm-up conditions were observed for flexibility and strength performance. Conclusions: Dynamic stretching is the most effective warm-up condition for performing vertical power in female athletes. Dynamic stretching is also better than static stretching in enhancing horizontal power and speed performance. Practical Applications: In real situation, although several kinds of warm-up condition would be performed in the warm-up protocol, dynamic stretching is suggested to be included, especially before power or speed exercises. Strength and conditioning professionals are encouraged to make dynamic stretching as the last warm-up condition just before the exercises in order to ensure the effectiveness.
Prolonged Static Stretching-Induced Alteration in the Relationship Between Motor Unit Recruitment Threshold and De-recruitment Threshold
X. Ye,1 T. Beck,1 N. Wages,1 J. Carr,2 and C. Miller1
1The University of Oklahoma; and 2University of Oklahoma
Static stretching (SS) is commonly used before exercise and athletic competitions. However, “stretching-induced strength loss” has been extensively reported, and is believed to be partially due to the reductions in muscle activation. Less is known regarding the influence of static stretching on motor unit control properties. Purpose: The purpose of this study was to examine the acute effects of a bout of repeated and prolonged SS on the relationship between motor unit recruitment threshold and de-recruitment threshold. Methods: Fourteen recreationally active men (mean ± SD age = 24 ± 5 years; height = 178.1 ± 8.2 cm; body weight = 83.8 ± 11.3 kg) performed 12 sets of 100-second passive stretches on their biceps brachii. Before (Pre) and after (Post) the intervention, isometric strength was tested during the maximal voluntary contractions (MVCs) of the elbow flexors. Subjects also performed separate submaximal trapezoid isometric contractions at 30 and 70% of their Pre- and Post-MVCs. Surface electromyographic (EMG) signals from the submaximal contractions were decomposed into individual motor unit action potential trains. The relationship between motor unit recruitment threshold and de-recruitment threshold was examined using linear regression analysis. Paired-samples t-tests were used to examine the possible changes in the isometric strength, as well as the linear slope coefficient and the y-intercept of the linear regression line for the motor unit recruitment threshold vs. de-recruitment threshold relationship. Results: The isometric strength of the forearm flexor significantly decreased (p < 0.001) following the SS intervention. In addition, significant increased mean linear slope (p = 0.024) and decreased mean y-intercept (p = 0.022) for the linear regression line were observed at 70% MVC following the SS, but not at 30% MVC. Conclusions: The increased linear slope and decreased y-intercept suggested that after the SS, motor units tended to de-recruit at higher force levels than at their recruitments. However, this phenomenon is contraction intensity-specific. Further research is needed to examine motor unit control properties under the stretches with shorter durations. Practical Applications: Due to the differential effects of static stretching on motor control strategy under different contraction intensities, strength and conditioning professionals should design different warm-up programs for athletes. For example, athletic performance that largely relies on low force production may not be disturbed by the previous static stretching; while caution should be taken when applying stretching protocol prior to athletic events that are heavily rely on high force production, as the stretching intervention may affect motor control strategy under this circumstance.
Influence of Combined Anti-inflammatory and Nutritional Supplements on Skeletal Muscle Recovery in Resistance-Trained Men and Women
S. Baggett,1 M. Esco,1 L. Cosio-Lima,2 M. Elmore,1 and P. Bishop1
1The University of Alabama; and 2The University of West Florida
Adequate recovery between exercise sessions is necessary for optimizing training benefits and avoiding overtraining syndrome. Improved recovery would allow athletes to train more rigorously without injury. Supplementation with a protein-carbohydrate beverage, an over-the-counter non-steroidal anti-inflammatory drug, and vitamins C and E immediately following a resistance exercise bout may influence skeletal muscle recovery. Purpose: To evaluate the influence of the concurrent use of ibuprofen, vitamins C and E, and a protein-carbohydrate (CHO) shake on skeletal muscle recovery. Methods: Fourteen resistance-trained (≥3 months, ≥ 2 sessions per week, ≥2 sets per exercise per session−1, ≥8 exercises involving all major muscle groups) individuals (mean ± SD age = 22 ± 3 years; training duration = 33 ± 33 months; session duration = 77 ± 23 minutes; frequency = 4 ± 1 d·wk−1; males, n = 7, females, n = 7) completed 2 experimental protocols, each consisting of 2 exercise sessions performed on consecutive days. On the first day, participants completed 3 sets of 8–12 repetitions at a load that ensured momentary muscular failure after each set. After 24 hours, participants attempted to repeat this same workout. On one occasion, participants consumed a protein-carbohydrate shake (330 ml; 20 g protein; 45 g CHO) and one dose each of vitamin C (1,000 mg), vitamin E (400 I.U.) and ibuprofen (100 mg) immediately after the initial workout. A second dose of vitamin C and ibuprofen were respectively consumed 1 hour or 30 minutes before the subsequent workout. On another occasion (counterbalanced) a placebo comprised of flavored water, 2 doses of an imitation vitamin (gummy candy), and 2 doses of placebo ibuprofen (sugar pill) was consumed in the same manner as the study treatment. Muscle pain and ratings of perceived exertion (RPE) were assessed following each set, exercise, and workout using a numeric 0–10 scale and a 10-cm visual analog scale (VAS). Residual pain and ratings of perceived recovery (RPR) were assessed after 24 hours. Performance–based recovery was measured as the number of repetitions performed on the second day of exercise. Results: The treatment enhanced performance–based recovery for the chest press (9 ± 2 vs. 8 ± 2; p = 0.004) and latissimus pull—down (10 ± 2 vs. 9 ± 2; p < 0.01) and reduced HR during the leg press (125 ± 16 vs. 133 ± 16; p = 0.005) and leg extension exercises (125 ± 15 vs. 131 ± 20; p = 0.049). When comparisons were made within each treatment, a significant (p ≤ 0.05) decline in performance for all exercises was observed after 24 hours under placebo conditions compared to decreased performance in only 50% of the exercises under treatment conditions. The treatment significantly enhanced RPR (6 ± 1 vs. 5 ± 1; p = 0.04) and reduced residual muscle pain (3 ± 2 vs. 5 ± 2; p = 0.005) compared to the placebo. Participants reported significantly lower RPE during the leg curl (6 ± 2 vs. 7 ± 1; p = 0.011) and shoulder press (7 ± 2 vs. 8 ± 1; p = 0.045) exercises under treatment vs. placebo conditions. Conclusions: Using these treatments may enhance muscle recovery following an exhaustive resistance bout, possibly by reducing muscle pain and RPE. Practical Applications: Athletes participating in multiple training sessions over 2 or more consecutive days may benefit from the use of a protein-CHO shake, vitamins C and E, and ibuprofen. However, prolonged use of this method for avoiding overtraining syndrome requires further investigation.
Effect of Far-Infrared Compression Garments on Recovery Following Acute High Intensity Eccentric Exercise
T. Barnette,1 E. Ryan,1 E. Roelofs,2 E. Trexler,1 H. Wingfield,2 A. Tweedell,1 M. Melvin,3 C. Kleinberg,1 E. Sobolewski,4 and A. Smith-Ryan1
1University of North Carolina, Chapel Hill; 2Wake Medical Hospital; 3Gaston County Schools; and 4Texas Tech University
Far-Infrared (FIR) emitting fibers have recently been incorporated into compression garments and have been suggested to aid in exercise recovery through elevated temperature, vasodilation, and reduced pain and discomfort. Purpose: The primary purpose of this study was to determine if a compression garment with FIR technology could improve post-exercise muscular performance, perceived muscle soreness, and plasma levels of creatine kinase following high intensity eccentric exercise. Methods: Eighty subjects (age = 22 ± 3 years) were randomly assigned to one of 4 treatment groups: (a) active apparel worn 60 minutes prior to and during the exercise testing with the placebo worn each night (n = 20); (b) placebo worn 60 minutes prior to and during the exercise testing with the active apparel worn each night (n = 20); (c) placebo worn 60 minutes prior to and during the exercise testing with the placebo worn each night (n = 20); and (d) active apparel worn 60 minutes prior to and during the exercise testing with the active apparel worn each night (n = 20). During exercise testing, each participant performed 10 sets of 15 eccentric isokinetic muscle actions of the leg extensors on the non-dominant leg at 60°·s−1 over a 90° range of motion with a 2 minute rest period between sets. Maximal voluntary isometric contraction (MVC) strength, Visual Analog Scale (VAS) scores for muscle soreness, and creatine kinase (CK) were assessed at baseline, 24, and 48 hours post exercise. Separate mixed factorial ANOVAs were used to analyze all variables of interest (MVC strength, VAS, CK). An alpha level of 0.05 was used for all tests. Results: For all variables, there was no significant time × treatment interaction (p ≥ 0.553) or main effect for treatment (p ≥ 0.268). However, there was a main effect for time (p ≤ 0.002) for each variable. Baseline MVC strength (179.0 ± 11.5 N·m−1) was significantly higher than 24 hours (164.3 ± 12.0 N·m−1) and 48 hours (166.7 ± 12.7 N·m−1) post exercise. Baseline VAS scores (0.213 ± 0.12) were significantly lower than 24 hours (2.46 ± 0.35) and 48 hours (2.54 ± 0.45) post exercise. Baseline CK values (147.0 ± 20.5 U·L−1) were significantly lower than 24 hours (396.1 ± 103.9 U·L−1) and 48 hours (347.1 ± 129.0 U·L−1) post exercise. Conclusions: Results of the current study demonstrated that 10 subsequent bouts of 15 isokinetic eccentric muscle actions of the leg extensors resulted in decreased isometric strength, increased perceived muscle soreness (VAS scores), and elevated CK values at 24 and 48 hours post exercise. However, the FIR garments did not appear to minimize any symptoms of muscle damage or provide greater recovery of strength compared to the placebo. Practical Applications: These findings suggest that FIR technology may have little impact on recovery following an acute bout of high intensity eccentric exercise; however, it is possible that FIR technology may be more beneficial during aerobic or dynamic exercise assessments.
Effects of Acute Ingestion of a Multi-Ingredient Pre-workout Supplement on Muscular Endurance
T. Blumenstein,1 G. Wright,1 C. St. Antoine,1 M. Jones,2 J. Oliver,3 and A. Jagim1
1University of Wisconsin–La Crosse; 2George Mason University; and 3Texas Christian University
Purpose: Multi-ingredient pre-workout supplements (MIPS) are becoming increasingly popular among resistance trained individuals. These products typically include similar ingredients with the most common being caffeine, creatine, beta-alanine, and branched-chain amino acids. There is evidence to suggest that some of the individual ingredients may improve muscular endurance by delaying central nervous system fatigue and enhancing skeletal muscle contractility. More specifically, MIPS may improve muscular endurance by delaying the onset of fatigue. The purpose of this study was to determine if short-term, MIPS ingestion influences muscular endurance. Methods: In a double-blind, randomized, placebo controlled, crossover design; 12 resistance trained males (18.8 ± 1.2 years; 180 ± 12 cm; 89.3 ± 11 kg; 13.6 ± 4.9% BF) had their body composition assessed followed by 5-repetition maximum (5RM) determination for the back squat (BS; 119.3 ± 17.7 kg) and bench press (BP; 92.1 ± 17.8 kg) exercises. On 2 separate occasions participants ingested 1 serving of an MIPS that contained 4 g carbohydrates, 2 g creatine hydrochloride, 3 g beta-alanine, 1.5 g betaine, 1 g taurine, 600 mg N-acetyl L-Cysteine, 150 mg alpha-glyceryl phoshporyl choline, 6 g citrulline malate, 500 mg beet extract, 6 g branch chain amino acids, 1.5 g L-tyrosine, 300 mg caffeine anhydrous, 50 mcg huperzine A and 5 mg BioPerine; or a placebo (P) 30-minutes prior to performing 5 sets of 5 repetitions at 85% of 5RM, followed by a single set to failure. Two minutes separated sets and BS preceded BP. Ten minutes of recovery was allowed in between tests. Participants returned a week later to perform a second testing session using counter treatment. Paired t-tests were used to compare differences between treatments. Results: MIPS resulted in a greater number of repetitions performed in the final set to failure in the BP (MIPS, 9.8 ± 1.7 reps; P, 9.1 ± 2; p = 0.027) resulting in a greater total volume load (set × reps × load) in the MIPS (753 ± 211 kg) compared to P (710 ± 226 kg; p = 0.032). No difference was observed in BS repetitions to failure (MIPS, 11.8 ± 3.9; P, 11.0 ± 3.6; p = 0.180) or total volume load (MIPS, 1159 ± 359 kg; P, 1089 ± 364 kg; p = 0.186). Conclusions: Results suggest that acute ingestion of a MIPS containing similar ingredients to those used in the current study may increase upper body muscular endurance, though no effect was observed in lower body muscular endurance. Practical Applications: Based upon the results of the current study, ingesting a MIPS prior to a training session may improve muscular endurance of the upper body, which could increase overall training volume of a session. Over time this may lead to improved training adaptations, however, additional research is needed to examine the optimal ingredient mix of MIPS that may enhance the overall quality of a training session as well as its long-term effectiveness.
The Effects of a Pre-workout Vegan Supplement on Cycling Performance Levels in a Sample of College Aged Males
G. Gallien, G. Davis, and D. Bellar
University of Louisiana at Lafayette
Individuals who exercise and live a vegan lifestyle may experience difficulty when trying to find an effective pre-workout supplement that does not contain any animal byproducts. No previous studies have examined the relationship between the use of a vegan supplement and exercise performance levels. Purpose: To examine the effects of a vegan pre-workout supplement on cycling performance levels in recreationally active college-aged men. Methods: Recreationally active college-aged men (n = 14; age = 22 ± 1.84 years; height = 178.99 ± 8.69 cm; body mass = 78.53 ± 11.61 kg) volunteered to participate in this study. Subjects completed a familiarization trial, which consisted of a graded exercise test, followed by 3 separate visits in which participants exercised at a workload that represented 80% of their V[Combining Dot Above]O2peak until exhaustion. Supplements were administered using a randomized, double-blind cross-over design and included (a) vegan pre-workout supplement (70 kcal), (b) an isocaloric sports drink, and (c) a zero-calorie drink with artificial sweetener. Each of the 3 exercise trails were separated by a minimum of 72 hours. For each trial, participants completed an overnight fast. Thirty minutes prior to testing, participants consumed one of the 3 supplements mixed with 12 ounces of water. Results: The average time in seconds (s) until exhaustion while using the vegan pre-workout supplement was 482 ± 163 seconds. The average time until exhaustion while using the isocaloric sports drink was 480 ± 157 seconds. The average time until exhaustion using the zero calorie drink was 496 ± 238 seconds. Conclusions: Consumption of the vegan supplement provided no ergogenic benefit compared to an isocaloric and zero-calorie drink for recreationally-active males while cycling at 80% of their V[Combining Dot Above]O2peak. Practical Applications: Since veganism has recently become a more popular practice, there has been an increase in vegan-friendly products available to consumers. The results of this study indicate that individuals who choose a vegan pre-workout supplement (over an isocaloric or zero-calorie product) will not experience any difference in exercise performance. Although the present study does not support the use of the tested vegan pre-workout supplement before cycling, further research is warranted in this area.
Comparison of BMI-Based Equations and Plethysmography for Estimating Body Fat in Female Competitive Collegiate Dancers
K. Casey, J. Casey, P. Bishop, and M. Esco
The University of Alabama
Optimal body fat percentage (BF%) is an important component of physical fitness that has been shown to influence athletic performance and health. However, in sports where aesthetics are a prominent aspect of the culture, such as competitive dancing, body image issues and disordered eating are common and inaccurate estimates of BF% may impact the psychological well-being of the athlete. Several regression equations have been developed to estimate BF% with body mass index (BMI). Due to their simplicity, these equations may be attractive for practitioners who have limited access to advanced measures, such as air displacement plethsymography (BODPOD). However, there is limited research available to determine the agreement between BMI-Based BF% equations and laboratory measures in competitive collegiate dancers. Purpose: The purpose of this study was to determine the agreement between 3 BMI-based equations and BODPOD for estimating BF% in competitive female collegiate dancers. Methods: Twenty-eight female, competitive collegiate dancers (age = 19.5 ± 1.0 years, height = 164.6 ± 6.2 cm, weight = 55.9 ± 5.2 kg, BMI = 20.6 ± 1.8 kg·m−2) participated in this study. Data were collected between December 2008 and October 2011. At each visit, BF% was measured with a calibrated BODPOD, body weight was measured with a calibrated digital scale, and height measured with a stadiometer. BF% was predicted by using 3 previously developed BMI-Based equations as follows: Jackson et al. (2002) (JABMI) = (4.35 × BMI) − (0.05 × BMI2) − 46.24; Deurenberg et al. (1991) (DEBMI) = (1.20 × BMI) + (0.23 × age) − 5.4; Womersley & Durnin (1977) (WDBMI) = (1.37 × BMI) − 3.47. Results: The measures of BF% produced the following results: 24.6 ± 4.6% with BODPOD; 21.9 ± 4.0% with JABMI; 23.8 ± 2.1% with DEBMI; and 24.7 ± 2.4 with WDBMI. The only significant difference found was between BODPOD and the JABMI (p ≤ 0.05). Moderate correlations were found between BODPOD and the BMI-Based equations (r = 0.43 for JABMI, r = 0.44 for DEBMI, r = 0.43 for WDBMI). The 95% limits of agreement for each BMI-Based equation compared to BODPOD were −9.1% fat for JABMI, 8.1% fat for DEBMI, and 8.2% fat for WDBMI. Conclusions: There were no significant mean differences between BODPOD and DEBMI and WDBMI; however, JABMI was significantly lower than BODPOD. Only moderate correlations were found between the BMI-Based equations and BODPOD. Notably, each BMI-Based equation had large limits of agreement relative to BODPOD. Practical Applications: Competitive dance is a sport where body image and eating disorders are problematic. Inaccurate predictions of BF% in athletes may exacerbate these pre-existing psychological issues. The results of this study suggest that a wide range of individual differences exists when comparing the BMI-Based BF% equations with BODPOD. Therefore, coaches and dieticians may need to consider other methods of predicting BF% in competitive collegiate female dancers.
Individual Y-Balance Test Reach Length and Functional Movement Screen Scores Are Related
L. Kelleher,1 T. Beach,2 A. Johnson,1 and J. Dickey1
1University of Western Ontario; and 2University of Toronto
Purpose: Both the Functional Movement Screen (FMS) and the Y-Balance Test (YBT) are used to evaluate key movement patterns, functional symmetry, and identify individuals that are at elevated risk of injury. Both depend on core strength, flexibility, and balance, and seem likely to be related. The purpose of this study was, therefore, to assess whether FMS scores are significantly correlated with the YBT reach distances. Methods: Sixty subjects (30 male; age = 28.3 ± 9.5; BMI = 24.1 ± 3.03) performed the 10 tests (7 movement tests and 3 clearing tests) of the standardized FMS protocol, followed by the YBT. The YBT protocol in this study comprised 4 bilateral practice trials in each reach direction—anterior, posterolateral, and posteromedial, followed by a rest break. Three test trials were then recorded bilaterally for each reach direction. The reach distances were normalized to leg length and averaged between sides and trials. The individual directions were evaluated, and were also summed to form an aggregate YBT score (TotalY). Results: Although the correlation between FMS and TotalY was not significantly different from zero (r = 0.17), the correlation between FMS and normalized anterior reach was statistically significant (r = 0.28; significant, p ≤ 0.05), as was the correlation between FMS and normalized posteromedial reach (r = 0.35; significant, p ≤ 0.05). This discrepancy is likely because the non-significant relationship between FMS and normalized posterolateral reach (r = 0.003) diluted the strength of the relationship between FMS and TotalY. Conclusions: Anterior and posteromedial reach lengths predict FMS performance, demonstrating partial correspondence between the 2 tests. Further research on the relationship between the YBT and global movement qualities should be undertaken to inform future training and rehabilitation strategies. Practical Applications: This is the first study to examine the relationship between the FMS and the YBT. Further research investigating the relationship between the 2 tests should be undertaken to determine if it is necessary to administer both the FMS and YBT to assess global movement quality, depending on the focus of the examination.
Pre-season and Post-season Aerobic Fitness, Body Composition, and Functional Movement Characteristics of High School Basketball Referees
J. Schuldheisz, R. Gabriel, E. Kosderka, and M. Gibo
Concordia University, Portland, Oregon
Most studies of the game of basketball have focused on the physiological and psychological demands on the athletes. With increased competition at the high school (HS) level, understanding of the “other participants,” the officials, is critical to meet performance expectations. Purpose: The purpose of this study was to investigate changes in aerobic fitness, body composition, and movement quality levels in HS basketball referees over the course of a competitive season of officiating. Methods: Thirty-two HS basketball referees (50.48 ± 10.6 years old) were randomly selected from a list of “regular members” (typically working varsity games). The ratio of subjects (n = 28 male, n = 4 female) reflected the gender proportion in the local high school officials' association. After completion of the IRB approved informed consent, health history, and Physical Activity Readiness Questionnaire (PAR-Q) forms, participants reported to the human performance lab for 2 testing sessions. Session One occurred 2–3 weeks prior to the season and Session 2 was within 2 weeks of the conclusion of the season, as determined by the state HS activities association. Each testing session lasted approximately 60 minutes and consisted of basic anthropometric measures, body composition testing using the BOD POD, movement quality screening via the Functional Movement Screen (FMS), and the 20-meter multi-stage Progressive Aerobic Cardiovascular Endurance Run (PACER). A standardized warm-up, pre-recorded instructions, PACER intervals, and cool-down protocol were used throughout the assessment period. T-tests for significant differences were conducted for weight, body composition, FMS, and PACER scores. Results: The referees' average weight (88.68 ± 15.86 kg pre-season, 88.63 ± 16.03 kg post-season) and average percentage of fat (26.04 ± 6.22 pre-season, 26.66 ± 6.07% post-season) did not change significantly from the beginning to the end of the season. The overall FMS scores showed a trend for a moderate, but not statistically significant improvement, from 11.22 (pre-season) to 11.78 (post-season). There was, however, an increase in the number of left to right asymmetries from 22 (pre-season) to 32 (post-season). In the PACER test, a significant post-season improvement was found with participants running nearly 4 more laps in the post-test (35.57) compared to the pre-season (32.28, p < 0.001). Conclusions: The HS basketball referees in this study did not significantly change body weight, percentage of fat or movement quality following a season of competition. However, the number of asymmetries did increase over the course of the season. The PACER test was the only dependent variable to significantly improve from the pre-season to the post-season. Practical Implications: This study provides a current evidence-based approach to formulating guidelines for preseason fitness levels, insights in to planning preseason training programs, and benchmarks for officials to maintain throughout the season. The results of this study provide evidence that an increase in physical activity, via officiating, over the course of a HS basketball season, can improve cardiorespiratory endurance. But an increase in conditioning comes with a decrease in movement quality as more asymmetries were developed during the season. With a direct link between greater asymmetries and more risk of injury, it is therefore advised that referees emphasize correcting movement issues throughout a season.
The Construct Validity of Two Methods of Performing and Scoring Pushups
University of Louisiana at Lafayette, School of Kinesiology
Purpose: The purpose of this investigation was to examine the relationships between 2 different methods of performing and scoring pushups (PU) to the constructs of absolute strength as measured by a 1 repetition maximum (1RM) bench press and relative strength (1RM per body mass). Methods: A Hand Release pushup (HRPU), popular with the Crossfit community, was performed by raising the hands from the floor between each PU so that the upper body weight rested on the floor; whereas, a standard PU involved the chest slightly touching the floor before returning to a locked support position. A metronome controlled standard PU rate at 84 b·min−1 (i.e., 2 beats/PU) with a slower rate of 72 b·min−1 used for the HRPU to allow for hand movement. Thirty-one college age male volunteers completed informed consents and physical activity readiness questionnaires. A counter-balanced research design was employed where subjects were randomly assigned to the different PU protocols, tested, then switched and retested after one week of recovery. The criterion measure was a 1RM Bench Press (i.e., absolute strength) and was conducted following one week of recovery from the last PU test. The 1 RM testing procedures employed a 2 set warm-up at approximately 60 and 80% of the subject's perceived 1RM followed by repeated 1RM efforts. The recorded lift was the maximum weight successfully lifted using a strict technique of no bouncing and a slight pause on the chest before returning to a locked position. Absolute strength scores were transformed to relative strength using a ratio scaling technique of 1RM per BM. Data were analyzed using a dependent t test with a 2 tailed hypothesis at an alpha level of 0.05 to determine if there was a significant difference in the maximum number of PU's executed. In addition, Pearson Product Moment correlation (PPMC) analyses were conducted to determine if there were statistically significant relationships between the PU test protocols and the criterion measures of absolute and relative strength. The alpha level was adjusted to 0.0125 for each of the 4 relationships of investigative interest. Results: Results indicated that participants were able to execute significantly more HRPUs (Mean = 36.7 ± 11.4) as compared to the standard method (Mean = 29.9 ± 8.5); t = 4.394; p = 0.0001. In addition, correlation analyses indicated that neither HRPU nor Standard PU's significantly correlated with absolute strength (i.e., r = 0.22 and 0.25, respectively). Both HRPU's and standard PU's significantly correlated with relative strength (r = 0.58; p = 0.0006 and r = 0.71; p = 0.0001, respectively). Conclusions: There was no evidence that of PU performance was related to aerobic capacity since the majority of the participants reached muscle failure in less than 60 seconds, making it a predominantly anaerobic endeavor. In addition; it was concluded that neither of these 2 PU tests were indicators of absolute strength. If however, the interest is to assess relative strength, a standard PU appears to be a better choice, sharing 50% of the variance between strength relative to body mass; whereas, the HRPU shared only 33.6%. Practical Applications: Pushup tests do not measure absolute strength & test duration is too brief to provide insight into endurance; however, both pushup tests may be acceptable measures for strength relative to body mass with the standard pushup being preferable to the hand release method.
Effects of Two Therapeutic Modalities vs. No Treatment on Acute Muscle Soreness
T. Kopec,1 E. HIbberd,1 S. Buser,2 C. Fister,2 and R. Otterstetter2
1The University of Alabama; and 2The University of Akron
Delayed onset muscle soreness (DOMS) is a physiological response to resistance exercise to which one is unaccustomed. The use of therapeutic modalities following a bout of eccentric-only exercise may enhance soft tissue healing and reduce DOMS. To date, there is conflicting evidence regarding the effectiveness of post-exercise electrostimulation (E-Stim) in reducing DOMS. Purpose: The purpose of this study was to compare 2 post-exercise therapeutic E-Stim modalities to no treatment on perceived DOMS-related rating of pain 24-hours following an intense bout of eccentric resistance exercise of the elbow flexors. Methods: Eight college students (aged 23 ± 3 years) volunteered to participate in this study. Each participant performed a fatiguing protocol that involved a drop-set of dumbbell biceps curls for the non-dominant arm that focused on eccentric activations only. The male participants started with a 30-pound dumbbell and the female participants began with a 25-pound dumbbell. Each participant was instructed to lower the weight at a timed pace of 3 seconds while the biceps group was eccentrically activated. Then, the participant used the uninvolved arm to assist the involved arm with flexing the elbow to return the weight to the starting position. Participants were instructed to perform as many repetitions as possible until the 3-second cadence could no longer be maintained. At that point, a dumbbell that was 5 pounds lighter was immediately selected and the same procedure repeated. This process continued until the participants reached a 5-pound dumbbell. Following the exercise protocol, participants were counterbalanced into 1 of 3 conditions: (a) non-invasive interactive neurostimulation (NIN) applied to the non-dominant arm's biceps brachii for 10 minutes; (b) a bipolar microcurrent electrical nerve stimulation (MENS) applied to the non-dominant arm's biceps brachii tendon for 20 minutes; or (c) a control condition of no treatment with the participants resting in the seated position for 20 minutes. Twenty-four hours following the protocol, the participants reported the level of localized pain to the biceps group by completing a graphic rating scale (GRS). The GRS determines the level of perceived pain by participants placing a mark along a 25-cm horizontal line that represents “No Pain” to the left and “Unbearable Pain” to the right. The greater the distance in centimeters from the left edge of the line to the participant's mark indicates greater pain. Results: The mean ± SD in subjective pain scores from the GRS 24-hours after DOMS induction for NIN = 8.54 ± 5.60 cm, MENS = 8.04 ± 5.19 cm, and control = 9.20 ± 3.67 cm. Neither NIN nor MENS treatments were significantly different when compared to the controlled condition (p = 0.78, Cohen's d = 0.14, and p = 0.61, Cohen's d = 0.26, respectively). Conclusions: The results of this investigation suggest that post-exercise treatment with NIN or MENS did not result in less pain in the biceps compared to no treatment following fatiguing protocol. Practical Applications: Practitioners need to be aware of the major findings of this study that when compared to when no post-exercise treatment is used, neither E-Stim device (i.e., NIN and MENS) provided reduced DOMS symptoms 24-hours after a bout of eccentric-based resistance exercise. Therefore, it is possible that E-stim modalities may not be more effective at attenuating DOMS than when no therapeutic intervention is utilized.
Screening Athletes for Heat Illness
J. Kazman,1 P. Riordan,1 P. Lisman,2 S. Golenbock,1 and P. Deuster1
1Uniformed Services University/Consortium for Health & Military Performance; and 2Towson University
Exertional heat illness (EHI) describes a continuum of symptoms observed in athletes who exercise in the heat. EHI is noted in about 6,000 people annually in US hospitals, and if untreated, can rapidly progress to exertional heat stroke (EHS), which can be fatal. Each year, 1 in 5 athletic trainers can expect to treat an athlete for EHS. Pre-participation exams (PPE) allow trainers and medical staff to identify athletes at greater risk for EHI. An 11-item PPE for EHI has been proposed by a panel of experts (Eberman and Cleary, 2011), but has yet to be validated. Another measure of EHI risk can be provided by a heat tolerance test (HTT). Purpose: This study assesses the relationship between a modified PPE and performance outcomes on a HTT. Descriptives for PPE items are presented, and relations between the PPE and HTT are explored among 31 healthy participants with no history of EHI. Methods: Participants completed a PPE, a HTT, and questions on other health measures. The PPE is an 11-item evaluation based on self-report and measured variables, with each item coded as 0 (no risk) to 4 (high risk) and summed for risk stratification. Items cover EHI history, health behavior patterns (nights slept without air conditioning (AC); recent nights with subpar sleep; motivation to compete; physical activity level; acclimation status; medication/supplement use), recent fever/illness, and lab measures (urine specific gravity [USG], body mass index [BMI] percentile, maximal aerobic power or V[Combining Dot Above]O2max). The HTT requires walking at 3mph on a 2% incline for 120 minutes, in an environmental chamber set at 40° C and 40% relative humidity. HTT outcomes include maximal heart rate (HR) and rectal temperature (Tr). Percent body fat (%BF) was also estimated using bioelectrical impedance analysis. Results: The mean PPE score was 14.3 ± 3.8; range 8–23. Based on PPE score, 55% of participants were classified as low risk (PPE ≤ 14) and 45% as moderate risk (15 ≤ PPE ≤ 29); none were high risk (PPE ≥ 30). Low and moderate risk participants differed along 4 items: sleep without AC, acclimation, USG, and V[Combining Dot Above]O2max. 19% of participants had 0 ratings of 4 (high risk) and 52% had 1 item with a 4. A rating of 4 was most common for acclimation (52%), motivation (32%), V[Combining Dot Above]O2max (19%), and sleeping in non-AC room (19%). PPE score correlated with HTT maximal HR (r = 0.37, p = 0.04), but not maximal Tr (r = 0.03, p = 0.9). Based on multiple regression, 36% of the variance in HTT maximal HR was accounted for by 2 PPE items: V[Combining Dot Above]O2max (β = 0.53, p < 0.01) and physical activity level (β = 0.31, p = 0.04). HTT maximal HR did not correlate with BMI percentile (r = 0.09, p = 0.64), but did with %BF (r = 0.43, p < 0.01). Conclusions: Among a relatively fit sample, a majority had a high risk rating on at least 1 category, but still had low to moderate overall risk. Athletes with a high PPE should be carefully monitored for EHI as the score, along with some individual items, may relate to an individual's heat tolerance based on a HTT. Although BMI percentile is 1 PPE item, %BF is a better indicator of HTT performance. Since the HTT is conducted under optimal conditions (euhydration, no medications/supplements), some PPE items may be underestimated and would not affect HTT. Practical Applications: The PPE is likely a practical tool to stratify athletes for risk of EHI. The HTT is more time-intensive, but might be useful for athletes with high PPE scores. Future work should assess the predictive value of the PPE and HTT in tandem.
The Relationship Between Convergence, Divergence, Recognition, Tracking Skills, and Batting Performance of Professional Baseball Players
F. Spaniol,1 J. Cruz,2 and T. Lawson2
1Texas A&M University–Corpus Christi; and 2Texas A&M University–Corpus Christi
Purpose: The purpose of this study was to investigate the relationship between convergence, divergence, recognition, and tracking skills and batting performance of professional baseball players. Methods: Three hundred fifty-two (352) minor league baseball players were evaluated for visual skills and batting performance during the 2013 minor league baseball season. Visual skills were measured using Vizual Edge Performance Trainer (VEPT), a software program which measures eye alignment, depth perception, convergence, divergence, visual recognition, and visual tracking. Individual subtest scores were recorded and combined to give an overall EDGE score. Visual skill testing was conducted by professional baseball scouts as part of pre-draft player evaluations. Visual skills composite EDGE score was determined by the subtest scores of convergence station score (CON), divergence station score (DIV), visual recognition response time (VR), and visual tracking response time (VT). Batting performance was determined by 2013 season statistics, which included batting average (BA), bases on ball percentage (BB%), strikeout percentage (SO%), on base percentage (OBP), slugging percentage (SLG), and on base plus slugging (OPS). Players were divided into quartiles based on each of the 4 VEPT variables. Results: Descriptive statistics was performed for all variables along with Pearson's correlation coefficient and independent samples t-test was used to analyze significant disparities between upper and lower quartiles. Statistical analysis displayed significant differences for VR and BA (r = −0.114, p = 0.035) and DIV and SO% (r = −0.096, p = 0.058). In addition, practical significance was determined through significant disparity between upper and lower quartiles of convergence and on base plus slugging percentage (0.702–0.719), recognition and slugging percentage (0.388–0.364), recognition and strikeout percentage (0.236–0.251), recognition and on base plus slugging percentage (0.726–0.694) and finally tracking and strikeout percentage (0.268–0.223). Practical Applications: The results suggest that there is a significant relationship between convergence, divergence, recognition, and tracking skills and batting performance. Coaches and training staffs should consider adding a variation of visual stimuli training to help gage and train the visual skills of professional baseball players.
Shoulder Strength and Pitching Velocity of a Collegiate Pitcher With a Type One Slap Tear Over a Competitive Season: A Case Study
D. Szymanski, R. Lueken, K. Cook, and J. Szymanski
Louisiana Tech University
Purpose: To evaluate shoulder strength and pitching velocity of a collegiate pitcher with a type 1 SLAP tear over a competitive baseball season and to determine if the comprehensive rehabilitation program for the shoulder was beneficial. Methods: A Division I baseball pitcher (age = 20 years; height = 193.0 cm; mass = 97.0 kg; %BF = 12.9%), who was diagnosed by a MRI arthrogram with a type 1 SLAP tear in his throwing shoulder prior to the beginning of the season, was recruited for this case study. The subject was evaluated and cleared to play by an orthopedic surgeon. A Biodex Isokinetic Dynamometer was used to measure shoulder isokinetic strength while performing a seated modified neutral shoulder external rotation (ER) and internal rotation (IR), a seated ER and IR at 90° of abduction, and a standing diagonal 2 (D2) flexion (Flex) and extension (Ext). Isokinetic testing was performed bilaterally for 5 repetitions at 90°·s−1 to compare strength of the throwing arm to the non-throwing arm at 3 different times during the 2014 baseball season; at the start of the season (March), in the middle of the season (April), and at the end of the season (May). Isokinetic testing was performed after a home weekend series in which the subject pitched and his fastball velocities were recorded. The subject was prescribed and completed a comprehensive shoulder rehabilitation program under the direct supervision of a certified athletic trainer (second author). Results: Repeated measures ANOVAs for each movement (ER/IR and Flex/Ext) of each arm (right and left) over the 3 testing sessions (March, April, May) over the baseball season were conducted and revealed several significant (p ≤ 0.05) main effects. Post hoc comparisons revealed that seated left arm modified neutral IR in April was greater than March (p = 0.002) and May (p = 0.001). Seated right arm modified neutral IR was significantly greater than right arm modified neutral ER for March (p = 0.014), April (p = 0.001), and May (p = 0.005). Seated right arm modified neutral IR in May was greater than left arm modified neutral IR in May (p = 0.001). Both seated right and left arm ER at 90° abduction in April (p = 0.001 and p = 0.001, respectively) and May (p = 0.005 and p = 0.001, respectively) were greater than in March. Seated right arm ER at 90° abduction was significantly greater than right arm IR at 90° abduction for March (p = 0.014), April (p = 0.009), and May (p = 0.033). Standing left arm D2 Ext in May was greater than in March (p = 0.004) and April (p = 0.005). Standing right arm D2 Ext was significantly greater than right arm D2 Flex for March (p = 0.001), April (p = 0.001), and May (p = 0.001). Standing left arm D2 Flex was significantly greater than left arm D2 Ext for May (p = 0.014). Standing left arm D2 Flex was greater than right arm D2 Flex for March (p = 0.007), April (p = 0.04), and May (p = 0.04). Standing left arm D2 Ext was greater than right arm D2 Ext in May (p = 0.02). A 1 × 3 ANOVA of mean pitching velocities (PV) for the 10 best fastballs over the course of the season were statistically different (p = 0.001). Post hoc analyses revealed that PV in April (40.10 ± 0.37 m·s−1) was greater (p = 0.001) than March (38.80 ± 0.19 m·s−1) and greater (p = 0.002) than May (38.89 ± 0.56 m·s−1). Conclusions: Nonsurgical treatment and training allowed a collegiate baseball pitcher with a documented type 1 SLAP tear to maintain or increase strength in both shoulders and pitch for an entire season without further complications similar to previous data. Nonsurgical treatment should be considered for baseball pitchers with documented type 1 SLAP tear, as it can lead to acceptable return to play and return to prior performance rates. Practical Applications: Labral pathologies are a prevalent injury in baseball pitchers. Recording shoulder strength and pitching velocity over the course of a season in a pitcher with a labrum pathology should influence the way athletic trainers structure their rehabilitation sessions, strength coaches structure their weight training programs, or how pitching coaches structure their weekly throwing routine for the pitcher. The comprehensive shoulder training program for this pitcher appears to be an effective rehabilitation plan. Further research with a larger sample size is needed in order to determine the efficacy of nonsurgical treatment and training for baseball pitchers since current data for this group is relatively unknown.
Lung Function in NCAA Division II Swimmers Over the Course of a Season
A. McRea, and A. Koch
Previous research has indicated chlorine exposure may have an adverse effect on lung function. Purpose: We measured lung function in competitive swimmers over the course of a season, to determine whether their lung function would change with increased exposure to a chlorinated pool. Methods: Fourteen NCAA division II swimmers (8 women, 6 men; age = 18 ± 1 year; height = 173 ± 8 cm; body mass = 71.9 ± 14.0 kg) were measured for forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and FEV1/FVC ratio at 3 time points: preseason (after 3 weeks removal from regular chlorine exposure), mid-season (at peak chlorine exposure, approximately 8 weeks @ 20 h·wk−1), and post season (approximately 2 weeks of removal from regular chlorine exposure). All measurements were obtained with a computerized spirometer. Data were analyzed using a repeated measures ANOVA, with statistical significance set at p ≤ 0.05. Results: ANOVA revealed no differences in FVC (p = 0.753), FEV1 (p = 0.988), or FEV1/FVC (p = 0.624) over the period of measurement. Conclusions: These data provide no evidence of an impaired lung function among swimmers exposed to chlorine. Practical Applications: Coaches can be confident that 2 months of 20 h·wk−1 exposure to a chlorinated pool will not result in any measurable deficits in lung function.
The Effects of Shoe Heel Height on Vertical Jump Performance
Dakota State University
Athletes are constantly looking for ways to gain an edge over their competition. They often try new training programs, experiment with new equipment, and consume new supplements to improve athletic performance. However, many do not think about the little things, such as shoes worn on game day, that may impact their performance. Purpose: To determine the effects of shoe heel height on vertical jump performance. Methods: Twenty-four female college students volunteered to participate in this study. The volunteers wore a pedometer and their own shoes with different heel heights (< 1 inch [flat], 1–2 inches [med], and >2.5 inches [high]) during a normal day for 3 non-consecutive days. At the end of each intervention day (around 4:00 PM), the number of steps was recorded and the vertical jump test was completed. Each subject performed a brief dynamic warm-up prior to performing 3–4 vertical jumps. A repeated measure analysis of variance (rANOVA) was used to determine the differences between the number of steps taken each day, and the 3 vertical jump measurements. Results: There was no difference in the number of steps taken (p = 0.1268) during the 3 intervention days (flat, 2,608 ± 885; med, 2,990 ± 1308; high, 3,077 ± 981). In addition, there was no difference in vertical jump height (p = 0.2311) between the 3 shoe interventions (flat, 16.5 ± 2.6 in.; med, 16.4 ± 2.3 in.; high, 16.2 ± 2.7 in.). Conclusions: This result suggests that vertical jump performance was not affected by the height of heels worn during the day regardless of the number of steps taken during the day. Practical Applications: Although a number of subjects reported having sore feet after wearing the high heels, vertical jump height was not affected. Female athletes can dress up, including high heels, on game days without worrying about negatively impacting their performance.
Growth Charts for Muscular Strength Capacity With Quantile Regression
M. Peterson, and C. Krishnan
University of Michigan
Introduction: Substantial evidence has demonstrated the importance of muscle strength preservation in the protection against cardiometabolic diseases, functional declines and musculoskeletal deterioration, and early, all-cause mortality. However, what remains to be established are sex-specific strength growth charts and curves using data from a population-representative sample and clinically-feasible measurement. Methods: A population representative sample of 7,119 individuals, aged 6–80 years, was included from the 2011–2012 National Health and Nutrition Examination Survey (NHANES) datasets. The analyses were performed in 2015. Grip strength was assessed using a hydraulic hand-held dynamometer, and peak force values were normalized per body mass. Parametric quantile regression was used to determine unique quantiles for men and women. The response was fitted with a parametric model, which involved 6 powers of age. Results: Growth charts and curves (see Figure) were created using output from the quantile regression from reference values of normalized grip strength corresponding to the fifth, 10th, 25th, 50th, 75th, 90th, and 95th percentiles across all ages. For men, starting from age 6, there was a small drop in normalized strength followed by a quick growth until about age 25 years. Among women there was gradual growth in normalized strength until about age 15 years. For both men and women, there was a decline in normalized strength throughout middle age and later adulthood; however, the rates of decline were greater among men. Conclusions: The established quantiles of normalized strength can easily be incorporated into a clinical setting for screening individuals that would benefit from lifestyle interventions to improve muscular fitness and reduce health risks. Practical Applications: The established quantiles of strength can easily be incorporated into a clinical setting for screening individuals that would benefit from lifestyle interventions to improve muscular fitness and reduce health risks.
Upper Body Muscle Endurance and Power Following Acute Supplementation With a Select Amino Acid Combination
B. Wax,1 A. Kavazis,2 E. Hall,1 A. Walton,1 B. Thebaud,1 J. Smith,1 and J. Townsend1
1Mississippi State University; and 2Auburn University
Glycine-arginine-α-ketoisocaproic acid (GAKIC) has been reported to enhance resistance performance during muscular strength and endurance protocols; however, there is a paucity of research regarding the effects on muscular power. Purpose: To investigate the potential ergogenic effects of GAKIC ingestion during repeated bouts of upper body resistance exercise during a power protocol. Methods: Ten resistance trained males (age = 20.8 ± 1.6 years, mass = 97.5 ± 15.7 kg, height = 1.84 ± 0.05 m) participated in a randomized, crossover, double blind study. Participants were randomly assigned to placebo or GAKIC (11.2 g) and performed 5 rounds of 2 sets of bench press at 75% of 1 repetition maximum, followed by 3 kneeling chest ball throws with a 3 kg power ball. Average peak velocity and power were also captured using a tendo unit on the bench press exercise. One week later, participants ingested the other supplement and the same exercise protocol was performed. Results: GAKIC supplementation failed to significantly increase bench press repetitions (GAKIC = 52.1 ± 13.9; placebo = 49.8 ± 13.4, p > 0.05), average peak velocity (GAKIC = 0.58 ± 0.12 m·s−1; placebo = 0.56 ± 0.10 m·s−1, p > 0.05), average peak power velocity (GAKIC = 498.8 ± 95.5 W; placebo = 482.9 ± 77.7 W, p > 0.05) or kneeling chest ball throw total distance (GAKIC = 30.4 ± 4.7 m; placebo = 29.8 ± 4.7 m, p > 0.05). Conclusions: These findings suggest that GAKIC does not increases power output during repeated bouts of upper body resistance exercise. Practical Implications: Our data suggests that acute GAKIC ingestion prior to an upper body resistance training protocol does not increase the repetitions and power output of trained males during a power protocol.
Motivation and Social Influences of Creatine Monohydrate, Protein, Nitric Oxide, Weight Loss, and Multivitamin Supplements Use in Louisiana High School Athletes
T. Piatolly,1 D. Hollander,2 B. Williams,2 M. Reynolds,2 A. Brown,2 and D. Toups2
1MYSPORTSDIETICIAN; and 2Southeastern LA University
While supplement use in high school athletes has been a focus of research in an ever-evolving supplement industry, personal and social influences need to be understood. It becomes imperative that strength and conditioning coaches understand the influences of behavior that can impact performance of their athletes and work toward positive influence through motivation and social pathways. Purpose: The purpose of the present study was to describe personal and social influences of creatine monohydrate, protein, Nitric Oxide (O2), weight loss, and multivitamin supplements in high school athletes. Methods: A surveyss study was administered to 25, 201 high school athletes and these surveys were returned. After careful screening of responses, 4,239 survey participants reported taking a supplement. Only 1,344 respondents reported which supplement was taken. These students' data were analyzed for the current study. Results: Athletes reported the following frequencies of use; protein shakes n = 461, creatine monohydrate n = 27, NO2 n = 19, weight loss products n = 14, multivitamins n = 130, and multiple supplements taken n = 660. These represent relatively small amounts of reported use. Analysis of importance of taking the supplement, (1 = very important to 3 = not at all) were reported from the highest rated score (via the lowest mean) and included improved strength (m = 1.72), increased size (m = 2.04), becoming a better athlete (m = 2.08), improved physique (m = 2.24), increased energy (m = 2.26), and decreased body fat (m = 2.64). Social influences were provided in the table below. The majority of athletes reported multiple sources of influence (50.2%), while the highest single influencers were parents (14%) and friends (6.6%). Conclusions: The athletes in the present sample demonstrated that protein shakes were the most often reported supplement used by high school athletes in Louisiana. Moreover, the motivation and priority reported by athletes was an increase strength and size. When queried about social influences, the athletes reported multiple sources, but clearly delineated parents and friends as social effectors. Practical Applications: For the study results, athletes in Louisiana report taking mostly protein shakes and are seeking increased strength and size. Their primary sources for information were reported to be multiple influences and athletes relied heavily on parents and friends. Thus it is important to educate parents as well as peers in high school about the impact and influences of supplement use in high school athletes.
Carbohydrate Mouth Rinsing and Caffeine Ingestion After Meal Does Not Influence Forty-kilometer Cycle Time Trial in Cycling Athletes
C. Lee,1 C. Cheng,2 W. Hsu,3 and M. Hsu4
1Physical Education Section of General Education/National Sun Yat-sen University; 2Department of Athletic Performance/National Taiwan Normal University; 3Graduate Institute of Sports Training/University of Taipei; and 4Department of Sports Medicine/Kaohsiung Medical University
It has been reported that carbohydrate mouth rinsing (CHO) improves short-term (less than 1-hour) endurance performance, and caffeine ingestion (CAF) improves exercise performance at varied intensities. However, the effects of CHO and CAF on physiological responses and short-duration, high-intensity endurance exercise effort, such as 40-km time trial, remain unknown. Purpose: In the real-life situation, many athletes consume a small carbohydrate-rich meal 2–3 hours prior to the training or competitive session. This study investigated the effects of CHO with and without CAF ingestion after a meal on exercise capacity, physiological responses, and hormone levels during a 40-km time trial in recreational cycling athletes. Methods: Sixteen recreationally trained male cycling athletes (mean ± SD: age 30 ± 4 years; height 1.75 ± 0.06 m; body mass [BM] 67.6 ± 7.9 kg; V[Combining Dot Above]O2max 54.5 ± 1.3 ml·kg−1·min−1) volunteered to participate in this randomly assigned, double-blind, counterbalanced study administering 5 mg·kg−1 BM of CAF or equal dose of cellulose (F, placebo), followed by a 6.6% CHO (glucose) solution or water (W) mouth rinsing. Visit one served as familiarization. During the following visits, participants performed the 40-km time trial test under variable treatments: CAFCHO, CAFW and FCHO. Participants mouth rinsed 25 ml of CHO solution or water 2-minutes before and at every 5-km during the 40-km time trial test. Blood samples were drawn before and after the 40-km time trial test to determine the metabolic and hormone responses, included the blood glucose, blood lactate, insulin, testosterone, cortisol, human growth hormone, and creatine kinase levels. Cycling speed, time to completion, heart rate, rating of perceived exertion (RPE), feeling scale, and arousal scale were measured during the 40-km time trial test. Two-way ANOVA (treatment × time) with repeated measures analysis was used to test mean difference in variables between 3 conditions. Results: Percentage changes in cycling speed and time to completion were not significantly different among treatments. No significant differences were found on mean heart rate (CAFCHO vs. CAFW vs. FCHO, 161 ± 2 vs. 163 ± 2 vs. 159 ± 2 b·min−1, p > 0.05) and RPE (CAFCHO vs. CAFW vs. FCHO, 14 ± 2 vs. 14 ± 2 vs. 14 ± 2, p > 0.05) among the treatments during 40-km time trial test; however, significant main effect across time were observed. No significant differences were found among treatments for feeling scale, arousal scale, metabolic and hormone responses. Conclusions: A 5 mg·kg−1 BM dose of CAF followed by mouth rinsing a 6.6% CHO solution does not affect hormone responses, pleasure-displeasure and arousal level, and 40-km time trial performance in fed cycling athletes. Further studies are needed to clarify the effects of CAF ingestion and CHO mouth rinsing on the performance in the sporting event which is longer than 1-hour. Practical Applications: Both caffeine and carbohydrate supplements are popular ergogenic aids among athletes in the real world. Long-distance athletes may benefit from CAF and CHO mouth rinsing while the muscle and liver glycogen stores are deficient. However, in the fed state, these data suggest that the ingestion of CAF capsule and CHO mouth rinsing may not improve 40-km time trial performance. The interferences induced by the fed or fasted state on the ergogenic effects of CAF and CHO mouth rinsing should be cautiously considered for coaches and athletes to optimize the nutritional strategies.
Effects of Ten Weeks Β-Alanine Supplementation on Peak, Power Drop and Lactate Recovery Rate in Korea National Team Boxer
K. Kim,1 D. Park,2 C. Kim,3 Y. Kim,1 H. Song,1 J. Chung,1 and M. Kim4
1Korea Institute of Sport Science; 2Inha University; 3Dongduk Women's University; and 4Hankuk University of Foreign Studies
Fatigue during boxing match is the main cause of increased muscle acidosis and therefore strategy to reduce muscle acidosis is necessary to develop boxing performance. It is currently considered that the β-alanine improves performance is through elevating muscle carnosine therefore enhancing muscle buffering capacity and reducing acidosis. Although the relationship between β-alanine supplementation and performance improvement has been continuously studied, research related to boxing on β-alanine supplementation still remains inadequate. Purpose: This study was designed to investigate the effects of β-alanine supplementation on peak power, power drop and lactate recovery rate in Korea national male amateur boxers. Methods: Participants of this study were 19 male amateur boxers in Korea national team. They were divided into the training group with β-alanine supplementation (TGB, n = 9) and training group with placebo supplementation (TGP, n = 10). TCB were continuously taking 4.9–5.4 g·d−1 of β-alanine with combined training for 10 weeks and TGP took placebo in the same way as TGB. To verify the effect of β-alanine supplementation and combined training, specific physical fitness and lactate changes in sparring were measured before and after the 10 weeks. Results: First, significant interaction effects were found between measurement times and the groups in peak power of lower limb (p = 0.049) and power drop of upper limb (p = 0.042). Second, significant interaction effects were found between measurement times and the groups in the 5 minutes after the sparring with respect to the lactate recovery rate (p = 0.036). Conclusions: Korea national amateur boxers who steadily took β-alanine generated significantly improves peak power of lower limb, power drop rates of upper limb and 5 minutes after the sparring with lactate recovery rate. And since there were no side effects or weight gain with β-alanine supplementation, this supplement may be particularly applicable in elite boxing players. Practical Applications: In case of β-alanine intake, most of studies apply short term intake (4–6 weeks) because of the price of supplement, participant control and stress of frequent intake (2–3 times per day). In this study, to reduce the intake frequencies (1 time per day), increase one time intake dose from 800 mg (10–15 mg·kg−1) to 1,650–1,800 mg (18–30 mg·kg−1) for 10 weeks. On the contrary to the former studies, which reported the side effects such as skin tingling, gastro-intestinal discomfort of exceed intake, there was no side effects shown at all. This can be the very significant result and also represent the needs of additional study depends on the races, genders, etc.
The Effect of Six Days of Alpha-Gpc Supplementation on Isometric Force Production
D. Bellar,1 N. LeBlanc,1 L. Judge,2 and G. Davis1
1University of Louisiana at Lafayette; and 2Ball State University
Ergogenic aides are widely used by fitness enthusiasts and athletes to increase performance. Alpha glycerylphosphorylcholine (A-GPC) has demonstrated some initial promise in changing explosive performance. Purpose: The purpose of the present investigation was to determine if 6 days of supplementation with A-GPC would augment isometric force production compared to a placebo. Methods: Thirteen college aged males (Means ± SD; Age: 21.9 ± 2.2 years, Height: 180.3 ± 7.7 cm, Weight: 87.6 ± 15.6 kg; V[Combining Dot Above]O2 max: 40.08 ± 7.23 ml O2*Kg−1*min−1, Body Fat: 17.5 ± 4.6%) gave written informed consent to participate in the study. The study was a double blind placebo controlled, cross-over design. The participants reported to the lab for an initial visit where they were familiarized with the isometric mid thigh pull in a custom squat cage on a force platform and upper body isometric test against a high frequency load cell, and baseline measurements were taken for both. The participant then consumed either 600 mg per day of A-GPC or placebo and at the end of 6 days performed isometric mid thigh pulls and an upper body isometric test. A one week washout period was used before the participants baseline was re-measured and crossed over to the other treatment. Results: The A-GPC treatment resulted in significantly greater isometric mid thigh pull peak force change from baseline (t = 1.76, p = 0.044) compared with placebo (A-GPC: 98.8 ± 236.9 N vs. Placebo: −39.0 ± 170.9 N). For the upper body test the A-GPC treatment trended towards greater change from baseline force production (A-GPC: 50.9 ± 167.2 N Placebo: −14.9 ± 114.9 N) but failed to obtain statistical significance (t = 1.16, p = 0.127). Conclusions: A-GPC is effective at increasing lower body force production after 6 days of supplementation. Practical Applications: Sport performance coaches can consider adding A-GPC to the diet of speed and power athletes to enhance muscle performance.
Effects of Chinese Herb Supplementation With Eccentric-Biased Resistance Training on Body Composition and Muscle Strength in Postmenopausal Women
H. Lin,1 C. Chou,2 H. Chao,1 Y. Tsai,3 and C. Chen4
1National Taiwan University; 2National Taipei University of Technology; 3National Taiwan Normal University; and 4University of Taipei
Eccentric exercise has been advocated for older population and antioxidant supplementation was recently shown to attenuate the benefit brought by exercise training. Chinese herbs are getting more popularity in many countries, and are advocated to provide antioxidant effects as daily supplements, yet whether muscular adaptation as well as body composition could be affected was never investigated. Purpose: to investigate the effects of 12-week eccentric resistance training with widely-used herb formula (panax ginseng and salvia miltiorrhiza) on body composition and strength in postmenopausal women. Methods: a double-blind randomized order was used and assign 16 apparently healthy and sedentary participants (age = 56 ± 1 year, height = 158 ± 1 cm, weight = 54 ± 2 kg, BMI = 21.8 ± 0.7 kg·m−2) into either the supplementation (S, N = 9) or the placebo group (P, n = 7). Both groups underwent 12 weeks of progressive unilateral eccentric leg extension exercise; supplementation group was fed with herbs (300 mg per capsule, 3 capsules) whereas the place took microcrystalline cellulose. Body composition and maximal isometric strength of knee extension were measured by using Dual-energy X-ray absorptiometry (DEXA), load cell respectively. Dietary record was also obtained before and after training. Results: DEXA measurements showed no significant change in bone mass density (BMD) on both thighs in the 2 groups, and the spine BMD decreased in both 2 groups after training instead (placebo: −2.43%, supplement: −2.92%) (p ≤ 0.05). There was also no difference on changes of body fat and muscle mass between groups; however, the maximal strength of right thigh was significantly improved in both groups (placebo: +20.3%, supplement: 4.9%) (p ≤ 0.05) and greater magnitude was observed in the placebo (placebo: 43.5 ± 4.3 kg, supplementation: 34.7 ± 2.1 kg) (p ≤ 0.05). Conclusions: our data showed eccentric resistance exercise did not appear to improve body composition. Panax ginseng and salvia miltiorrhiza supplementation along with training was likely to attenuate strength gain, instead of muscle mass in postmenopausal women. Practical Applications: antioxidant supplementation like the Chinese herbs used in current study appeared to bring no beneficial effects to people who want to gain muscle strength by doing eccentric exercise training.
Restrictions of Personal Protective Equipment on Mobility and Range of Motion on Firefighters
G. Ryan,1 K. Carver,1 R. Herron,2 S. Bishop,3 C. Katica,4 and G. Long1
1University of Montana Western; 2Auburn University at Montgomery; 3Montevallo University; and 4Pacific Lutheran University
Firefighting personal protective equipment (PPE) and accessories provide limited protection in potentially hazardous environments. However, PPE also induces fatigue, and may impede movement due to the weight and bulky nature of the gear. Purpose: The purpose of this experiment was to determine the effects PPE had on full body range of motion (ROM) of 10 experienced firefighters. Methods: Participants underwent a battery of ROM tests under both the control (undergarments) and PPE conditions. The test battery measurements included: (a) cervical rotation and flexion and extension; (b) shoulder flexion, extension, and abduction; (c) elbow flexion and extension; (d) lumber flexion and extension; (e) hip flexion, extension, and abduction; (f) knee flexion and extension; and (g) ankle plantar and dorsiflexion. Participants were asked to go to full ROM during each measurement. All measurements were taken on both sides of the body, and were measured to the nearest degree using a goniometer and recorded. Data was averaged and analyzed using an ANOVA, with post-hoc t-tests conducted on all significant findings. Results: A significant omnibus result was observed between the control and PPE group (p < 0.001). Post-hoc analysis indicated multiple significant differences: cervical rotation (C: 89.5 ± 1.6°, PPE: 81.7 ± 6.2°, p = 0.001); cervical extension (C: 90.0 ± 0.0°, PPE: 87.4 ± 3.0°, p = 0.02), right shoulder extension (C: 80.7 ± 12.7°, PPE: 71.3 ± 7.9°, p = 0.02); left shoulder flexion (C: 175.4 ± 11.1°, PPE: 167.1 ± 15.0°, p = 0.05), extension (C: 83.6 ± 10.1°, PPE = 74.8 ± 7.0°, p = 0.04), abduction (C: 177.9 ± 3.3°, PPE: 170.1 ± 13.0°, p = 0.04); left elbow flexion (C: 137.2 ± 9.2°, PPE: 128.6 ± 9.3°, p = 0.04); left knee flexion (C: 75.0 ± 12.2°, PPE: 86.5 ± 7.5°, p = 0.01); right ankle plantar flexion (C: 46.6 ± 10.0°, PPE: 37.4 ± 7.0°, p < 0.001); and left ankle plantar flexion (C: 44.1 ± 8.7°, PPE: 38.0 ± 8.2°, p = 0.003). No significant differences existed between the other variables measured. Conclusions: These findings suggests that PPE has a significant, but varying detrimental effect on ROM of firefighters over the body, including a potentially non-dominant side response, as more differences occurred on the left compared to the right side of the body. Practical Applications: These findings could provide benefit to firefighters and manufacturers to understand the restriction of PPE and improve design for safety and comfort of individuals wearing PPE. Additionally, understanding the restrictions of PPE could help strength and conditioning specialists design programs to improve functional strength in firefighters wearing PPE.
Ratio and Allometric Scaling of Vertical Jump and Vertical Jump Power in College Football Players
B. Mann,1 M. Bird,2 J. Mayhew,2 J. Houser,3 and W. Brechue3
1University of Missouri; 2Truman State University; and 3A.T. Still University
The vertical jump (VJ) is a primary method for assessing lower-body power (LBP) in college football players. Comparisons among players are typically accomplished using absolute (cm) or ratio (cm·kg−1 body mass [BM]) standards. These approaches may underestimate the power characteristics and unfairly penalize players at the upper end of the strength:BM continuum. Allometric scaling has been proposed as a method of normalizing the distribution of raw variables and providing equality of distribution along the continuum. Purpose: To compare absolute, ratio, and allometrically scaled standards for evaluating VJ and force/power characteristics of the VJ in college football players. Methods: NCAA Division-II players (n = 41, age = 19.8 ± 1.2 years, 183.7 ± 6.1 cm, 101.3 ± 18.8 kg) performed VJ trials with a Vertec and on a force plate to measure peak force, and peak and average jump power from which jump height was calculated. Light (LT, n = 20) and heavy (HV, n = 21) groups were constructed by dividing the sample at the median BM. Results: VJ was significantly greater when measured with the Vertec (64.9 ± 9.5 cm) compared to the force plate derived measurement (45.9 ± 7.6 cm) by 42 ± 11%; however, the 2 measures were highly related (ICC = 0.932). The LT group (48.8 ± 5.7 cm) had significant higher VJ than the HV group (43.1 ± 8.3 cm). MANOVA indicated that HV produced significantly greater peak force and peak power than LT, while LT produced significantly greater force per kilogram and peak force per kilogram than HV. There were no differences in average power and average power per kilogram between groups. Linear regression of log-transformed values for each test indicated no significant group interaction and hence the common exponent principle was upheld. When force and power was scaled using the derived exponents from the current data and the standard exponent (BM0.67), there were no significant differences between the BM groups for any force or power measurement. Conclusions: Allometric scaling of jump power tests may be more appropriate for comparing college football players of different BM. While ratio scaling may be acceptable for comparing average power produced during jumping in players of different BM, it may penalize players with high BM. Practical Applications: While vertical jump height is the standard for assessing LBP, it is impacted by BM and obscures the performance indicator. If the objective of evaluating LBP among college football players is to discriminate training efficacy and/or player potential then a more equitable and useful comparison along the BM continuum would be achieved with allometric scaling with the standard exponent.
Speed, Agility, and Power Based Tests in Young Athletes
M. Femrite, and P. Appicelli
Winona State University
Evaluating the health, fitness, and performance of individuals is useful for determining areas in need of improvement, setting personal goals, and evaluating the effectiveness of training. While this is important for all individuals, testing and measuring performance is particularly emphasized in athletes. Traditionally, most of this testing has been performed on high school, college, and professional athletes. In contrast, there is limited data on young athletes. However, there is an increasing amount of training being done by young athletes. Therefore, there is a need to have normative and comparative data available for evaluation. Purpose: The purpose of this study is to provide reference and comparative data for young athletes in performance based tests. Methods: Forty five participants (female n = 20, male n = 25) of ages between 9 to 13 year old participated in this study. Subjects completed the following tests: vertical jump, T-test, pro-agility, edgren test, 5 and 10 m sprints. Data for males only were collected for 5 and 10 m sprints. Statistical comparison of results based on gender was performed via independent t-tests. Results: There was no significant gender difference in vertical jump or pro-agility. The mean vertical jump for males was 0.330 ± 0.070 m while females was 0.297 ± 0.059 m. The mean pro-agility for males was 5.87 ± 0.44 seconds while the females was 6.03 ± 0.13 seconds. Five and 10 m sprint data for males was 1.562 ± 0.085 seconds and 2.500 ± 0.139 seconds, respectively. Between males and females, the only significant difference (p ≤ 0.05) in test results were the T-test and edgren tests. The mean T-test for males was 11.86 ± 1.05 seconds while the females was 13.22 ± 1.06 seconds. The mean edgren test for males was 28 ± 4 while the females was 25 ± 2. Conclusions: There is minimal difference in athletic performance in youth based on gender. However, tests that involve a substantial horizontal shuffling component suggest a small but significant difference. Practical Applications: Practitioners can use these data for comparative purposes for evaluating young athlete performance.
The Differences in Mean and Peak Power Output During Brief High Intensity Cycling Exercise Separated by Various Passive Recovery Intervals
S. Mitchell,1 P. Hoppmann,1 M. Finn,1 R. Henderson,2 and P. Norrell1
1The University of South Alabama; and 2The University of Alabama
Repeated bouts of exercise are often performed during the same training session, and recovery is a critical element in performance. If an individual is not given enough time to recover from an acute bout of exercise, performance will decrease. When considering the literature examining recovery between bouts of high-intensity intermittent exercise, results are mixed. Furthermore, the development of power is contingent on exercise intensity and recovery. Purpose: The purpose of this study was to determine the effects of various passive recovery intervals on mean and peak power output between repeated short-term bouts of high-intensity intermittent cycling exercise. Methods: Participants included healthy, physically active males (n = 20). A 27.5 inch wheel off-road bicycle adapted to resistance load software was used to calculate performance markers for this study. Each testing protocol was separated by one week's time and protocol order was randomly assigned to each participant. Prior to assessment of performance markers, participants were familiarized to the equipment and testing protocol. After familiarization, participants performed a standardized warm-up, followed by three 30-second high-intensity tests, each separated by a specific recovery interval (protocol 1 = 10 minutes, protocol 2 = 15 minutes, protocol 3 = 20 minutes). The resistance load was based on the participant's bodyweight. Following each exercise trail, participants were instructed to refrain from movement and sit passively. Results: Results from the repeated measures ANOVA for mean power between exercise trials were significant for exercise protocols 1 and 2 (p ≤ 0.001, p ≤ 0.001). For protocol 1, further post-hoc analyses revealed a significant difference between trials 1 and 2 (p ≤ 0.001), trials 1 and 3 (p ≤ 0.001), and trails 2 and 3 (p ≤ 0.001). For protocol 2, significant differences were shown between trails 1 and 3 (p = 0.002) and trials 2 and 3 (p = 0.018). There were no significant differences in mean power between exercise trials for protocol 3. Results from the repeated measures ANOVA for peak power were significant between exercise trials for protocol 1 (p ≤ 0.001). Within protocol 1, post-hoc analysis revealed a significant difference between exercise trials 1 and 3 (p = 0.002) and between exercise trials 2 and 3 (p = 0.008). There was no significant difference in peak power between exercise trials 1 and 2. Finally, a repeated measures ANOVA showed no significant differences in peak power between exercise trials for protocols 2 and 3. Conclusions: Mean power outputs between exercise trials were reduced during the 10 minutes and 15 minutes protocols, suggesting these allotted times may not be long enough to allow for recovery. However, mean power output was not significantly reduced between exercise trials when they were separated by 20 minutes of passive recovery. When considering peak power, output was only significantly reduced when exercise trials were separated by 10 minutes of passive recovery. Conversely, peak power was not significantly reduced when exercise trial were separated by 15 or 20 minutes of passive recovery. Practical Applications: If the goal of an individual's cycling training is to increase both mean and peak power outputs during brief high-intensity intermittent exercise, results from the present study suggest separating bouts by at least 20 minutes of recovery.
The Relationship Between Vertical and Horizontal Stiffness and Maximal Running Speed in 11–15 Year Old Boys
R. Lloyd,1 R. Meyers,1 M. Hughes,1 J. Cronin,2 and J. Oliver1
1Cardiff Metropolitan University; and 2Aukland University of Technology
Purpose: Leg stiffness has been established as an important predictor of maximal running speed in male youth  and research has shown that vertical stiffness properties increase naturally from childhood to adolescence . However, the examination of both vertical and horizontal stiffness development and their respective relationships with maximal running speed in male youth remains unclear. Consequently, the aim of the current study was to establish how vertical and horizontal stiffness relate to maximal running speed in a large cohort of school age boys. Methods: Three hundred and thirty-six boys (aged 11–15 years) were analyzed for sprint performance over a 30 m track that included an optical measurement system (Optojump, Microgate, Italy) positioned at floor level for the final 15 m section . Vertical and horizontal stiffness were calculated from contact and flight times  from the 2 fastest consecutive strides for each participant over 2 trials. Inclusion criteria required participants to reach maximal speed during the 15–30 m section; those who had already achieved maximal speed before the data collection zone or were still accelerating at the end of the data collection zone were removed from analysis. One-way ANOVAs and Pearson correlation coefficients were used to determine any significant between group differences and the strength of relationships between vertical and horizontal stiffness (absolute and relative values) and maximal running speed respectively. Results: Between group differences are presented in Table 1 for both absolute and relative measures of vertical and horizontal stiffness. Whole group analysis showed that all 4 measures of stiffness were significantly correlated with maximal running speed (p ≤ 0.05). The strength of the correlations for absolute and relative vertical stiffness components were large (r = 0.5) and very large (r > 0.7) respectively, while the strength of relationships for relative and absolute measures of horizontal stiffness were small (r < 0.3). Conclusions: Absolute vertical stiffness increases significantly while absolute horizontal leg stiffness remains relatively unchanged in boys with advancing age. When normalized for leg length and body mass, vertical stiffness appears to increase post-peak height velocity (PHV) while horizontal stiffness declines. Both absolute and relative vertical stiffness appear to correlate more strongly with maximal running speed than horizontal stiffness. Practical Applications: The current study reinforces the importance of vertical stiffness for maximal running speed and consequently exercises that promote rate of force development and high velocity movement speeds should be a key training focus for developing sprint speed in male youth. The decrement in relative horizontal stiffness seen in the post-PHV participants will likely reflect an increased limb length and greater reliance on muscular power and technical factors that can produce high amounts of net positive horizontal force.
References:  Chelly, SM, and Denis, C. Med Sci Sports Exerc 33: 326–333, 2001.,  Lloyd et al. J Strength Cond Res 25: