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Medicine & Science in Sports & Exercise:
doi: 10.1249/01.mss.0000433641.29449.e5
Abstract

B-32 Free Communication/Poster - Running Performance: Assessment, Training, and Interventions

Free Access

May 29, 2013, 1:00 PM - 6:00 PM

Room: Hall C

682 Board #158 May 29, 3:30 PM - 5:00 PM

Physiologic Changes in Subjects During Simulated 50 and 100 Mile Ultra-marathon Runs

Robert S. Van Zant, Justin Grogg, Jennifer Szostek, Jason Exposito, Meghan Carroll. The University of Findlay, Findlay, OH.

(No relationships reported)

Physiologic stresses of body systems during ultra-marathon (>26.2 miles) runs may not only impair performance, but also threaten the athlete’s health. Little is known of the systematic physiologic changes in ultra-marathon runners before, during, and after such events.

PURPOSE: The purpose of this study was to frequently examine body weight (BW), blood parameters, nutrient (Kcal, CHO, fat, protein, Na, K, Mg) and fluid intake, urine output and vital signs of 4 recreational runners completing 50 or 100 mile ultra-marathons.

METHODS: Four subjects (1 male, 3 female; Age 35.5+5.4 y; VO2peak 52.9+7.2 ml.kg-1.min-1) participated in a simulated 50 (3 female) or 100 (male) mile ultra-marathon run on a controlled 5-mile asphalt loop course with minimal elevation change. One month prior to the run, all subjects underwent laboratory measures (BMI, percent body fat, blood lactate (BL) and glucose (BG), VO2peak, submaximal VO2 replicating intended run protocol). Complete blood count (CBC) was measured 1 hr pre-event and post event in all subjects. During the event BW, HR, SBP, DBP, BG, BL, RPE, lower extremity (LE) VAS pain rating, nutrient/fluid intake and urine output were measured every 5 miles. BW, nutrient/fluid intake, urine output and BG were measured 24 hr before and after the event.

RESULTS: No significant differences were noted between pre- and post event measures in BW, fluid intake, BG, and urine output. WBC, neutrophil (NEU) and monocyte (MON) blood levels were significantly (p<0.05) elevated 1 hr post event. Macronutrient intake was increased (p>0.05) 24 hr post event, and Mg intake was decreased (p<0.05) compared to pre-event. LE VAS was 4.75/10 (L) and 5.25/10 (R) 1 hr post event, decreasing to 2/10 (L&R) 72 hr post event. Event results (mile 5-50) showed no significant differences for BW (0.65 kg loss) and stable ranges for BG (17mg.dl-1), BL (0.1 mM), HR (12 bpm), SBP (17 mmHg) and DBP (9 mmHg). Subjects consumed on average 3,058 Kcal (74% CHO, 19% fat, 7% protein) and 7,155 ml fluid, and excreted 1,388 ml urine during the event.

CONCLUSIONS: Subjects maintained BW and BG with stable HR and BP responses during an ultra-marathon run and, with exception of Mg, had similar 24 hr post event nutrient consumption compared to pre-event diet. WBC, NEU and MON were increased 1 hr post event, as was LE VAS ratings up to 72 hr post event.

683 Board #159 May 29, 3:30 PM - 5:00 PM

No Difference in Metabolic Efficiency in Barefoot and Shod Conditions in Experienced Mid-Forefoot Runners

Kevin R. Vincent, Cindy Montero, Bryan P. Conrad, Joseph Wasser, Clarissa Lomonaco, Matthew Martenson, Heather K. Vincent. University of Florida, Gainesville, FL.

(No relationships reported)

It is not yet clear whether metabolic efficiency is different in barefoot and shod conditions in experienced mid-forefoot runners.

PURPOSE: This study compared the oxygen cost, metabolic parameters and select biomechanical variables between barefoot and shod running in trained mid-forefoot runners (N=21).

METHODS: men and women (30.0±10.9 years; 82% men, 15.6% body fat) performed two separate 20 minute treadmill running bouts at ∼77% of maximal heart rate. Rate of oxygen consumption (VO2), energy cost, fuel use and heart rate (HR) were collected continuously using a portable gas analyzer. Average exercise bout values, and values obtained at 3, 12, and 19 min were evaluated to determine whether condition differences occurred during the exercise bout. Three dimensional motion capture and force plates were used to determine kinematic and kinetic variables.

RESULTS: Participants ran at 185 ± 20 m/min for both conditions, at intensities corresponding to HR values of 146 bpm (shod) and 144 (barefoot). The oxygen cost area under the curve (AUC) values in the shod and barefoot conditions were 1461 ± 203 ml/kg*min and 1415 ± 222 ml/kg*min, respectively. The total energy expended in the shod and barefoot conditions was 974 ± 134 kJ and 979 ±142 kJ. The average non-protein respiratory exchange ratios, proportions and amount of fat and carbohydrate used were not different between conditions. Cadence was 2.5% higher and stride rate was 3% (p<.05). Peak ground reaction forces were higher in the shod condition compared to the barefoot condition (1756 ± 310 N versus 1703 ± 285 N; p<.05), and the vertical displacement of the center of gravity was less in the barefoot condition by 0.5cm.

Discussion: In trained mid-forefoot runners experienced with barefoot running, there are not significant metabolic differences and fuel use patterns between shod and barefoot running conditions longer than a few minutes in duration. It is likely that experienced participants were able to titrate kinematics and muscle activation to standardize energy output and fuel use for a given running distance and speed irrespective of shoe wear. Sponsored by the UF Sports Performance Center, and UF Running Medicine Clinic

684 Board #160 May 29, 3:30 PM - 5:00 PM

Comparison of Running Efficiency Wearing the Vibram FiveFingers® and Conventional Running Shoes

Steve Cusack, Susan Kwiecien, Deborah Atwell, Laura D’Amore, Corynne Pereira, Kimberly Pereira, Stephanie Rude, John Wygand, RM Otto, FACSM. Adelphi University, Garden City, NY.

(No relationships reported)

Human Performance Laboratory, Adelphi University, Garden City, New York 11530

The use of alternative footwear for activities of daily living, as well as recreational and sport participation is gaining popularity. A recent movement toward minimalist footwear, such as Vibram FiveFingers® (V5F) has its roots with barefoot locomotion. For individuals accustomed to a life of cushioned and raised heel footwear, the change may be traumatic, affect the biomechanics of locomotion and impact movement efficiency.

PURPOSE: Metabolic efficiency was evaluated to determine the acute and chronic (2 week adaptation period) effects of walking (80.4 m/min= W) and running (214.4 m/min = R) for subjects novice to wearing minimal footwear.

METHODS: 8 male and 6 female recreational athletes (age 22 ± 4 yrs), who were unfamiliar with wearing minimal footwear, were fitted for V5F and immediately performed the acute (A) trials of W and R with randomly assigned V5F footwear or the subject’s own running shoes (S) in a crossover design. After a 45 minute rest period, the crossover trials were conducted. Metabolic efficiency was obtained by open circuit spirometry at a 1% treadmill elevation. After a minimum 168 hour adaptation (14 days x ≥ 12 hrs/day) to minimal footwear, all subjects repeated the trials as part of the post-test.

RESULTS: For the 8 trials, VO2 (mL kg-1 min-1) was obtained for Pre S, Pre V5F, Post S and Post V5F (13.78±1.0, 13.49±1.0, 13.77±1.3, and 13.70±1.0) and (41.72±2.9, 41.24±3.1, 41.26±3.2, and 40.95±3.2) for W and R trials, respectively. There were no significant differences (P>.05) between V5F and S treatments in relation to VO2 , RR, VE, and HR within W and R trials, either acutely or following adaptation.

CONCLUSION: Adaptation to minimal footwear does not affect metabolic efficiency. The use of minimal footwear did not provide an advantage over standard running shoes despite a reduction in shoe mass (μ 217g). Chronic use of minimal footwear may provide alternative biomechanical stress of the lower extremity; however, the consequences are unknown.

685 Board #161 May 29, 3:30 PM - 5:00 PM

Marathon-Related Changes in Heart Rate and Heart Rate Variability

Vanessa Franco, David Salcido, Stacy Gerstel, Priya Khorana, Clifton Callaway, David Hostler, FACSM. University of Pittsburgh, Pittsburgh, PA.

(No relationships reported)

Recreational running confers multiple health benefits, but marathon running requires prolonged exertion that can result in cardiac events in amateur runners. Outside of studies in elite runners, there are few data about cardiovascular changes during a marathon.

PURPOSE: We sought to determine how heart rate (HR) and heart rate variability (HRV) change during a marathon and during recovery.

METHODS: We recorded continuous ECG from 8 recreational runners (75% male, aged 37±5) before, during, and after a marathon (completion time 3:00:10 to 5:14:30). We determined HR and HRV (standard deviation of RR-intervals) during 3-minute segments pre-race and at 6.2, 15, and 20 miles, during the last 3 minutes of the race, and post-race. RMANOVA was used to compare HR and HRV during the marathon. Resting HR and HRV were compared pre- and post-marathon using paired t-tests.

RESULTS: There was a great deal of variability in individual runners’ cardiac response to the marathon. Across all runners, HR did not significantly change throughout the course of the marathon. In contrast, HRV varied with time during the race (p < 0.05). Specifically, HRV increased from 0.007-0.008 ± 0.001-0.002 (range of means ± SEM) during the first 20 miles to 0.012 ± 0.002 during the last 3 minutes of the race. Resting HR increased from 80±3 bpm before to 93±6 bpm after the marathon (p = 0.059) while resting HRV decreased from 0.06±0.01 before to 0.04±0.01 after the marathon (p = 0.12). The magnitude of change in HR and HRV from pre- to post-marathon was not correlated with total finish time.

CONCLUSIONS: We found evidence that HRV increases near the end of a marathon in spite of a relatively constant HR during the same interval. Additionally, there is considerable variation among runners. Since all runners completed the marathon without cardiac issues, it is unclear whether increased HRV towards the end of the race represents a compensatory response or a pathophysiologic change that predisposes to further cardiac events. More data are required to determine if variations in HRV across time are a consistent feature of marathon runners.

686 Board #162 May 29, 3:30 PM - 5:00 PM

Influence of the Menstrual Cycle Phases on Running Economy

Elaina Mertens, Jessica Chow, Tracey Matthews, Vincent Paolone, FACSM. Springfield College, Springfield, MA.

(No relationships reported)

Maximal oxygen consumption (VO2max) is the most established method for predicting endurance performance, but when comparing two runners with similar VO2max levels, running economy (RE) is considered a reliable method for analyzing endurance running capabilities. The menstrual cycle may be an important component in RE as the increase in progesterone during the luteal phase of the menstrual cycle causes an increase in VE at rest. Increased resting VE is coupled with an increase in resting oxygen consumption, therefore it is hypothesized that increased progesterone levels may cause an increase in submaximal oxygen consumption and decrease in RE.

PURPOSE: To determine the influence of menstrual cycle phase on RE at a submaximal intensity.

METHODS: Nine eumenorrhoeic, fit distance runners (Mean ± SD: 20 ± 2 yrs, 57.54 ± 6.22 ml/kg/min for VO2peak) completed two 40 min submaximal runs: one during the mid-luteal phase and one during the mid-follicular phase at a velocity equivalent to 80% VO2peak. Dependent variables included rating of perceived exertion (RPE), respiratory exchange ratio (RER), breathing frequency (Fr), heart rate (HR), ventilation (VE), and VO2, and were measured at baseline and every 5 min during the submaximal runs. The running velocity was held constant, and therefore the submaximal VO2 represented RE. Repeated measures ANOVAs were utilized to examine if any differences or interactions existed for menstrual cycle phase and time for the dependent variables.

RESULTS: No significant difference (p >.05) existed in RPE, RER, Fr, HR, VE, or RE based on menstrual cycle phase.

CONCLUSION: There was no change in VE at baseline during the mid-luteal phase, possibly due to a lower than expected increase in progesterone levels, which may be common in fit distance runners. This suggests there may be a progesterone threshold level necessary to elicit increases in resting VE and oxygen consumption. There is no disadvantage for fit endurance runners physiologically when running at a submaximal intensity based on menstrual cycle phase.

687 Board #163 May 29, 3:30 PM - 5:00 PM

Changes in Running Form and Economy in Trained Male Endurance Runners Switching to Barefoot Shoes

Alexander T. Sougiannis, Michael W. Olson, Juliane P. Wallace, FACSM. Southern Illinois University Carbondale, Carbondale, IL.

(No relationships reported)

Minimalist running has been suggested to decrease force of impact on the heel and allow the runner to transition to a more forefoot strike style of running. However, there are many opponents of minimalist running who claim that minimalist running alters the type and not the incidence of injuries. There are also speculations as to whether minimalist shoes actually improve running economy in comparison to traditional running shoes.

PURPOSE: The purpose of this study was to analyze the biomechanical and metabolic differences between minimalist shoes and traditional running shoes in a novice runner.

METHODS: In a pilot study, one subject performed three separate running trials; a VO2 max test, and two 30 min run tests at 2.4m*s-1; one with traditional running shoes (TS), one with minimalist running shoes (MS). Reflective markers were positioned on the right side of the subject to monitor kinematics using a multi-camera system. Sagittal plane kinematics were observed over each 30 min session for 10 s at 5, 15, and 25 min running intervals. Kinematics variables of interest were: average foot angle, average leg angle, average ankle angle, leg angle at initial foot contact (IC), foot angle at IC, and the ankle angle at IC. VO2 and RER were collected continuously using a Medical Graphics metabolic cart.

RESULTS: VO2/kg, VO2, and RER showed consistent values in the two shoe types (TS; VO2/kg: 24.69 ±5, VO2: 2116.3 ±621.5, RER: 0.97 ±0.035, MS; VO2/kg: 28.1 ±4.9, VO2: 2409.9 ± 427.2, RER: 0.96 ± 0.045). No between condition differences were observed in the kinematics. There was a difference within the MS at 25 min for foot angle IC as midfoot contact (2.3 ± 1.5°) with greater plantar flexion (95.8± 0.9°) gradually transitioned to a heel contact (11.5 ± 3.2°) with more ankle dorsiflexion (88 ± 3.5°) (t=0.011 and t=0.021 respectively). The trend of the variability of the ankle angle increased in both conditions denoting a function of task, but the linear trend for the foot angle continued in the MS condition (r2 = 0.88) but not in the TS condition (r2 = 0.08).

CONCLUSION: There are no significant changes in running economy with first time use of minimalist shoes. Kinematics data can be used to infer that novices to MS running can transition gait patterns during long duration runs, but these changes are highly variable and indicate a prolonged learning period.

688 Board #164 May 29, 3:30 PM - 5:00 PM

Lower Body Muscle Activation is Similar When Running on Curved Non-motorized and Flat Motorized Treadmills

Luke R. Garceau, Kristof Kipp, Christopher Geiser, Andrew J. Starsky. Marquette University, Milwaukee, WI. (Sponsor: Paula E. Papanek, FACSM)

(No relationships reported)

Curve shaped, non-motorized treadmills have been recently developed and incorporated into rehabilitation facilities. It is unknown if the curved design imparts similar muscular demands, when compared to a standard flat motorized treadmill.

PURPOSE: Curve shaped, non-motorized treadmills have been recently developed and incorporated into rehabilitation facilities. It is unknown if the curved design imparts similar muscular demands, when compared to a standard flat motorized treadmill.

METHODS: Fourteen (7 female, 7 male) experienced endurance runners (mean ± SD: age = 20.5 ± 1.9 years; height = 174.21 ± 8.17 cm; body mass = 66.56 ± 8.22 kg) volunteered for this study. Subjects were outfitted with bipolar surface electromyography (EMG) electrodes on the right gluteus maximus, biceps femoris, rectus femoris, gastrocnemius medial head, and tibialis anterior. Testing consisted of three ten-minute conditions of treadmill running. The CT condition was performed on the curved treadmill at an intensity of “13” on Borg’s RPE scale. The other two conditions were performed at a zero percent grade on the motorized treadmill; the ST-RPE condition matched [CT] for RPE while the ST-S condition matched [CT] for running speed. Rectified smoothed EMG data from 24 strides per subject, per condition, per muscle, were used to calculate the peak (pkEMG) and average (avgEMG) EMG throughout the gait cycle. Repeated measures ANOVAs with Tukey HSD post hoc testing were used to make comparisons between the three test conditions for both variables assessed. The a priori alpha level was set at α = 0.05.

RESULTS: Analysis revealed significantly greater tibialis anterior pkEMG in the ST-S (0.103 ± 0.029 mV) and ST-RPE (0.110 ± 0.025 mV), when compared to the CT (0.075 ± 0.020 mV) condition (p < 0.005).

CONCLUSION: When running on a curved non-motorized treadmill, experienced endurance runners exhibited significantly lower peak muscle activation of the tibialis anterior, as compared to running on a standard flat motorized treadmill. However, besides the tibialis anterior, muscle activation of lower body musculature is similar when running at a matched speed or effort on a curved non-motorized and standard flat motorized treadmill.

689 Board #165 May 29, 3:30 PM - 5:00 PM

Effect of Yoga on Mile Time Performance in Male High School Runners

Brigid C. Nash, Tamara D. Hew-Butler, FACSM. Oakland University, Rochester, MI.

(No relationships reported)

Previous studies suggest that yoga exercises, specifically sun salutation flow of postures, may counteract tendon tightness, increase tendon elasticity, increase endurance running performance, and decrease the likelihood of injury.

PURPOSE: To determine if a one-week yoga intervention would improve flexibility, muscle tightness and mile time performance in male high school distance runners.

METHODS: 13 healthy male track distance athletes were recruited to participate in this randomized-control crossover study. Self-reported muscle tightness ratings (1: min - 10: max), posterior leg flexibility (sit and reach test) and mile time performance were assessed at baseline. Athletes were then randomized into two groups: the experimental group (A) underwent a 20 minute yoga intervention twice a week for 20 minutes while the control group (B) trained per usual. After a 1-week “washout” period, the groups were switched, with the former control group (B) undergoing yoga twice per week while the former experimental group (A) trained per usual. At the end of each intervention week, self-reported muscle tightness, flexibility and mile time performance were assessed.

RESULTS: No significant (p<0.05) differences were noted between the: yoga intervention; control condition; or baseline measures (mean±SD: yoga; control; baseline conditions, respectively) with regards to: muscle tightness (5.4±1.9; 6.7±2.5; 6.6±1.9), sit and reach flexibility (1.7±3.3; 2.2±2.6; 2.5±3.2 inches), or mile time performance (372.2±28.6; 372.6±33.0; 377.0±33.7 seconds). Compared to baseline (the “change” value: yoga or control minus the baseline value) non-significant trends were noted for the yoga intervention to: increase muscle tightness (1.3±1.6 vs. 1.2±1.7), decrease actual muscle tightness (0.4±1.6 vs. 0.7±1.7 inches), and increase performance (0.4±18.9 vs. 4.8±18.8 seconds) compared to the control condition (yoga vs. control, respectively).

CONCLUSION: Yoga practiced 20 minutes twice a week for one week did not significantly alter feelings of muscle tightness, sit and reach flexibility or mile time performance compared to the control condition. A trend towards increased mile time performance (4 seconds), however, was seen following the yoga intervention.

690 Board #166 May 29, 3:30 PM - 5:00 PM

Physiological Change in Experienced Adolescent Distance Runners After 12 Days at Altitude

Scott N. Drum, FACSM1, Hillary M. Clark2. 1Northern Michigan University, Marquette, MI. 2Western State Colorado University, Gunnison, CO.

(No relationships reported)

Physiological adjustments in young, sea level trained runners living and training at altitude for a short time has not been extensively explored.

PURPOSE: This study investigated the physiological changes in adolescent runners who trained and lived at altitude for a short duration. We hypothesized that improvement in performance variables at altitude would occur after about ten days (or the average length of stay).

METHODS: Twenty-four adolescent distance runners (male, n = 15) who attended and trained at a high altitude (> 7,700 ft above sea level) running camp were chosen for this study. A maximal oxygen uptake (VO2max) test via gas analysis was performed within 1-3 days of arrival at altitude from sea level and the same test protocol repeated after approximately 12-days of living and training above 7,700 ft. VO2max, time of fatigue (TOF), heart rate max (HRmax), and ventilation threshold (VT) were calculated and used as the primary variables. Paired t-tests were performed between pre and post VO2max tests on each major variable. A Bonferonni adjustment was made so that significance was set at P < 0.01.

RESULTS: Age, height, weight, body mass index (BMI), and time at altitude were obtained for each runner and included, respectively (mean ± SD): 16.1 ± 1.1 yrs, 170.3 ± 8.8 cm, 56.4 ± 7.4 kg, 19.4 ± 1.6 kg·cm2-1, and 11.9 ± 2.0 days. The following variables changed significantly over approximately 12-days from pre- to post-test, respectively: VO2max (54 vs. 57 ml·kg-1·min-1, P = 0.002), TOF (16.4 vs. 17.1 min, P = 0.008), and VT (2.7 vs. 2.8 L/min, P = 0.002). HRmax from pre- to post-test, respectively, did not significantly improve (188 vs. 187 bpm, P = 0.151).

DISCUSSION: In adolescent experienced distance runners arriving at altitude from near sea level, it seems they adjust comfortably after about 12-days of residency and training. In theory, oxygen delivery (i.e., cardiac output) and uptake improved along with tolerance to the build-up of metabolites despite no improvement in HRmax. Additionally, we speculate this group of young runners may also have begun to improve their total hemoglobin mass. This needs further study. Overall, it seems safe and effective for young runners to live and train high. Beyond 12-days at moderate altitude they might begin to feel stronger during workouts. This also requires further investigation.

691 Board #167 May 29, 3:30 PM - 5:00 PM

Breath-by-Breath Respiratory Exchange Ratio Variability Increases With Marathon Training

Scott R. Brown, George R. Biltz, Greg S. Rhodes, Chris J. Lundstrom, Stacy J. Ingraham. University of Minnesota, Minneapolis, MN.

(No relationships reported)

Currently, respiratory exchange ratio (RER) is used to assess changes in substrate utilization with endurance training. The results of RER studies have been inconclusive with respect to interpreting training response. Time series analysis of heart rate variability has shown that measures of variability can correlate with training effect. This study applies time series variability analysis to RER variability in novice marathon runners before and after training. Sample entropy (SampEn), a nonlinear method for variability analysis of time series data, characterizes the inherent regularity of a data sequence. A higher entropy score implies decreased predictability of sequential values - less self-similarity of the data. Submaximal, steady state RER time series variability, measured by SampEn, showed a statistically significant increase with marathon training.

PURPOSE: To assess the effects of 16 weeks of marathon training on RER variability, measured by SampEn, in college age, novice marathon runners.

METHODS: Fifty-nine novice runners (39 female, 20 male, ages 18-24), from a marathon- training course offered at the University of Minnesota, volunteered to participate in the study. Subjects underwent 16 weeks of marathon training along with pre-and post-training lab testing, which included: 2-mile time trial, VO2 max, and body composition by hydrostatic underwater weighing. RER variability was determined pre- and post-training by a 6-minute steady state run at 65% of their predicted VO2 max, based on concurrent 2-mile time trial. Gas exchange data was collected using a Medgraphics Ultima metabolic cart. SampEn analysis of RER variability was calculated using Kubios software. Matched pair t-tests were used to compare average RER and SampEn scores pre- and post-training.

RESULTS: SampEn measure of RER time series variability significantly increased from pre- to post-training (0.198 +/- 0.387, p = 0.0002). However, mean RER only trended to decrease with training (-0.012 +/- 0.079, p = 0.231). Subjects showed increased RER variability during sub-maximal steady state running after 16 weeks of marathon training.

CONCLUSION: Average SampEn scores for participants increased with marathon training. SampEn analysis of RER time series may detect trainability or metabolic adaptations with endurance training.

692 Board #168 May 29, 3:30 PM - 5:00 PM

Comparison of Running Energy Reserve Index (RERI) with Anaerobic Speed Reserve (AnSR)

Govindasamy Balasekaran, FACSM1, Nidhi Gupta1, Visvasuresh Victor Govindaswamy2. 1Nanyang Technological University, National Institute of Education, Human Bioenergetics Laboratory, Singapore, Singapore. 2Texas A & M University at Texarkana, Texarkana, TX.

(No relationships reported)

Running Energy Reserve Index (RERI) has been proven to be an accurate method in predicting run performances from sprint to middle distances (Balasekaran et al., 2011). However, the RERI have not been compared with a similar prediction technique such as the Anaerobic Speed Reserve (AnSR, Bundle et al., 2003).

PURPOSE: To compare RERI with AnSR technique.

METHODS: Fourteen trained athletes were recruited for this investigation (M ± SD; age: 25.1 ± 5.2 years, body mass index: 22.0 ± 1.6 kg·m-2, body fat percentage: 12.7 ± 3.9%, maximal oxygen consumption (VO2max): 55.09 ± 6.58 ml·kg-1·min-1). RERI is a ratio of maximal aerobic energy (EMAS) and maximal anaerobic energy (EMAnS) corresponding to maximal anaerobic speed (MAnS) and maximal aerobic speed (MAS), respectively while AnSR is a difference of maximal speed calculated using maximal anaerobic power (Spdan) and anaerobic power (Spdaer). To determine MAS, athletes performed six laboratory tests which were as follows: Astrand modified VO2max running protocol, submaximal discontinuous treadmill protocol, oxygen consumption (VO2) till exhaustion (Tlim) tests at velocity at VO2max (vVO2max) and at velocity below 95% of vVO2max [Vsub%95; median of velocity at lactate threshold and vVO2max (νΔ50) or νΔ50+5%vVO2max], and a series of run speeds on the treadmill to determine the speed and duration curve. MAnS was ascertained by a 50 m sprint on the track. The EMAS and EMAnS were determined at corresponding maximal speeds with a submaximal efficiency equation. Athletes also performed a protocol to determine Spdaer, speed corresponding to maximal aerobic power with a submaximal efficiency equation, and a 3s treadmill protocol to determine Spdan, highest speed at which the eight steps were completed successfully.

RESULTS: The RERI (2.33 ± . 24) was significantly correlated (r =.86, p < .0001) with AnSR (4.52 ± .53 m·s-1). The Bland and Altman plot indicated low mean bias (2.18) and narrow limits of agreement (2.87 to 1.50) between both methods.

CONCLUSION: Results indicate that the two methods, RERI and AnSR which are based on maximal aerobic and anaerobic energies are similar. Thus, RERI may be utilized as a comparable alternative to predict running performances.

693 Board #169 May 29, 3:30 PM - 5:00 PM

Reliability of Running Energy Reserve Index (RERI)

Nidhi Gupta1, Govindasamy Balasekaran, FACSM1, Visvasuresh Victor Govindaswamy2. 1Nanyang Technological University, National Institute of Education, Human Bioenergetics Laboratory, Singapore, Singapore. 2Texas A & M University at Texarkana, Texarkana, TX.

(No relationships reported)

Running Energy Reserve Index (RERI) has been proven to be an accurate method in predicting run performances from sprint to middle distances (Balasekaran et al., 2011). However, its reliability is unknown.

PURPOSE: To determine the reliability of RERI.

METHODS: Eight healthy untrained participants were recruited for this investigation [M ± SD; age = 27.6±2.8yrs, height =165.3±9.5cm, BMI = 23.8±2.1kgm-2, %BF = 26.2±5.8%, maximal oxygen consumption (VO2max) = 39.14±4.7mlkg-1min-1]. RERI is a ratio of maximal aerobic energy (EMAS) and maximal anaerobic energy (EMAnS) corresponding to maximal anaerobic speed (MAnS) and maximal aerobic speed (MAS), respectively. To determine MAS, athletes performed six laboratory tests which were as follows: Astrand modified VO2max running protocol, submaximal discontinuous treadmill protocol, oxygen consumption till exhaustion (Tlim) tests at velocity at VO2max (vVO2max) and at velocity below 95% of vVO2max [Vsub%95; median of velocity at lactate threshold and vVO2max (νΔ50) or νΔ50+5%vVO2max], and a series of run speeds on the treadmill to determine the speed and duration curve. MAnS was ascertained by a 50m sprint on the track. The EMAS and EMAnS were determined at corresponding maximal speeds with a submaximal efficiency equation. For reliability, the protocols to calculate RERI were repeated under identical conditions with the same participants on another day with a rest period of three-four days in between tests. Linear regression analysis was employed to determine speed-VO2 relationship to calculate EMAnS and EMAS. The positive exponential and hyperbolic non-linear regression equations were utilized to calculate MAS. The test-retest (inter-class correlation), Bland and Altman plot and coefficient of variation statistical techniques were utilized to determine reliability of RERI.

RESULTS: Test-retest trials of RERI revealed no significant differences (test = 2.30±.21 and retest = 2.27±.19, p ≥ .05) with a high correlation (r = .97, p ≤ .001) between tests. There was also low mean bias (.029), narrow limits of agreement (.133 to -.075) and low coefficient of variation (1.64) between repeated measurements.

CONCLUSION: Results indicate that the determination of RERI can be replicated in exercise settings with a high degree of reproducibility.

694 Board #170 May 29, 3:30 PM - 5:00 PM

Does Endurance Training Alter Energy Balance?

Brittany Inlow1, Birgitta Baker1, Conrad P. Earnest, FACSM2, Laura K. Stewart1. 1Louisiana State University, Baton Rouge, LA. 2University of Bath, Bath, United Kingdom.

(No relationships reported)

An examination of the effects of a training program that maximizes caloric expenditure may help gain a better understanding of potential strategies that may be used in future exercise training programs targeting weight loss.

PURPOSE: The purpose of this study was to explore whether endurance training alters energy balance via changes in resting metabolic rate (RMR), daily energy expenditure (EE) and energy intake (EI) in beginning marathon runners.

METHODS: Twenty-four individuals (17 females, 7 males; 21 + 0.3 years old) were assigned to one of two groups: 1) endurance (EN; n = 12), or 2) active control (AC; n = 12). The EN group completed 15 weeks of marathon training while the AC group maintained their usual exercise routine. Pre- and post-training primary outcome measures included: estimated VO2max (1.5 mile run/walk time), anthropometric indices, RMR (indirect calorimetry), EE (Actigraph Acceleromters), EI (3-day dietary intake). Additional measures of EE and EI were also obtained during a period of high running volume (Week 10) in both EN and AC groups.

RESULTS: At baseline, the EN group had significantly higher estimated VO2max values, and higher EE rates than the AC group. The EN group significantly increased EE during the tenth week of training (p = 0.009), while the AC group did not significantly change from baseline to Week 10. Analyses of post training measurements (Week 14) revealed that both the EN and AC groups significantly increased daily EE from baseline measures (p = 0.005) and both groups decreased time to complete 1.5 miles (p = 0.022). There were no changes in body weight, RMR, or EI (p > 0.05) during the course of the study.

CONCLUSION: The results of this study suggest that beginning runners following a marathon training program may experience an increase in EE without a concomitant increase in EI. Although marathon training improves cardiorespiratory fitness, changes in RMR and body weight do not appear to be likewise affected.

695 Board #171 May 29, 3:30 PM - 5:00 PM

The Reliability of Running Economy Expressed as Oxygen Cost and Energy Cost in Distance Runners

Andrew J. Shaw1, Stephen A. Ingham2, Barry W. Fudge2, Jonathan P. Folland, FACSM1. 1Loughborough University, Loughbrough, United Kingdom. 2English Institute of Sport, Loughbrough, United Kingdom.

(No relationships reported)

Running economy (RE) is commonly expressed as oxygen cost (OC); providing an index of ATP turnover at submaximal running speeds. Differences in substrate utilisation between repeated assessments could inflate between test variability of OC, reducing the reliability of this measure. Calculations of energy cost (EC) utilising the RER might mitigate for varying substrate utilisation, perhaps providing a more reliable assessment of RE.

PURPOSE: To compare the between test reliability of OC and EC measurements of RE in highly trained competitive runners, and contrast these reliability values with the smallest worthwhile change (SWC) in these measurements from a larger cohort of runners.

METHODS: Twelve trained male endurance runners (mean ± SD: age, 28 ± 6 yrs; VO2max, 76.0 ± 5.9 ml.kg-1.min-1) performed three discontinuous submaximal running assessments, separated by 7 days, each consisting of seven 3 min stages (1 km.hr-1 increments) to determine the reliability of OC (ml.kg-1.km-1) and EC (kcal.kg-1.km-1) at the 4 speeds below lactate turnpoint. Using the same submaximal protocol, the SWC for OC and EC were calculated from the between subject variation of RE assessed in twenty eight highly trained male endurance runners.

RESULTS: Low levels of within subject variation were seen for Oc and Ec measures of RE across the 3 submaximal assessments (Typical error of measurement (TE) < 3.85%; ICC > 0.73). No notable differences in TE were apparent between measures of OC and EC at any speed. When averaged across the four speeds, the TE (Oc, 2.74 vs Ec, 3.14%) was greater than the SWC (Oc, 1.13 vs Ec, 1.66%).

CONCLUSION: RE expressed as an OC and EC provided similarly high levels of reliability for highly trained endurance runners when assessed using a short-duration incremental submaximal exercise protocol. However, only when alterations in OC or EC exceed the TE can practitioners confidently interpret a meaningful change in RE when using the current protocol.

696 Board #172 May 29, 3:30 PM - 5:00 PM

Size Independent Economy of Locomotion is the same between Trained Male and Female Distance Runners

Leo J. D’Acquisto1, Amber Green2, Ryan Perkins1, Robert Pritchett1, Kevin Adkisson1. 1Central Washington University, Ellensburg, WA. 2University of Idaho, Moscow, ID.

(No relationships reported)

PURPOSE: The primary purpose of this investigation was to compare economy of locomotion between trained male and female runners when controlling for size dependent parameters such as resting metabolism, mass and stature.

METHODS: Trained male (M, N= 9) and female (F, N= 10) distance runners underwent anthropometric testing, resting metabolic assessment, and performed submaximal and maximal treadmill runs. Oxygen uptake (indirect calorimetry), HR (telemetry), and blood lactate (Bla) responses were monitored during the runs.

RESULTS: M runners were heavier (∼16%), taller (∼4%), and had a greater resting (standing) oxygen uptake (∼11%) compared to F (P<0.05). At a submax running effort of 12.9 km.hr-1, F ran at a greater speed relative to their stature (body lengths per minute; 128+5 vs 123+4, p<0.05). At this speed, (1) absolute rate of O2 uptake was greater in M (2.8+0.1 vs. 2.3+0.1 l.min-1, (p<0.05)), (2) net, mass specific O2 uptake was 36.9+1.1 (M) & 37.0+1.5 (F) ml.min-1.kg-1 (P>0.05), (3) size independent oxygen cost (SIC) for M and F was 0.300+0.029 & 0.289+0.034, respectively (P>0.05; SIC defined as net VO2 (ml) to move 1 kg body weight a distance equal to stature (McCann & Adams, 2003)), and (3) females had a greater HR (169+12 vs 145+8 bpm), blood lactate (3.2+1.4 vs 1.9+0.6 mM), and ran at a greater %VO2 max (80.6+8.4 vs 66+4.7)(p<0.05). M performed the max test at ∼16% greater speed (p<0.05) but at a similar %VO2 max (p>0.05) when compared to the F. M had a greater VO2 max (4.2+0.1 vs. 2.9+0.1 l.min-1 & 61.4+1.0 vs. 49.5+1.0 ml.min-1.kg-1) (P<0.05), whereas respiratory exchange ratio, peak Bla and HR were similar between M and F for the max run.

CONCLUSIONS: When controlling for differences in resting metabolic rate, mass and stature, females and males were found to have the same oxygen uptake at a given submaximal running speed, suggesting equal economy of locomotion independent of body size.

697 Board #173 May 29, 3:30 PM - 5:00 PM

The Effect of Shod Versus Barefoot Running on Lower Limb Muscle Activation

John K. Petrella, FACSM, Chase Inman, Alexis T. Bauer, Alan P. Jung, FACSM. Samford University, Birmingham, AL.

(No relationships reported)

PURPOSE: Little research has focused on the effect of footwear on lower limb muscle activation. While increased muscle activation may result in increased speed, a negative effect may exist for distance walking and running which includes muscle fatigue and injury. The purpose of this study is to determine the effects of being shod or barefoot on lower limb muscle activation when walking and running.

METHODS: Six college-aged men (n=2) and women (n=4) participated in the protocol (21.4±1yrs, 178.3±8cm, 83.8±26 kg). Average electromyography (EMG) amplitude (mV) over a 15 second measurement period was recorded for the tibialis anterior (TA), peroneus brevis (PB), medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SO) and peroneus longus (PL) Recordings were taken during the last 15 seconds of 3 minutes of walking (0.55 m/s) or running (3.6 m/s). Separate trials of barefoot or shod were completed for each speed. All trials were counterbalanced with 2 minutes recovery between trials. All EMG activity was recorded, transformed, and reported as root mean square (RMS) activity.

RESULTS: As expected, running increased muscle activation for all lower limb muscles from walking to running, regardless of being barefoot or shod (p<0.05). When comparing barefoot to shod during walking, there was no significant difference in EMG activity of any muscle (p=0.16 - 0.87). However, EMG activity during barefoot running was reduced in the PL (11%, p=0.04) and tended to be lower in the soleus (23%, p=0.07) compared to shod running.

CONCLUSIONS: Some lower limb muscles show reduced neural activation when running barefoot.

698 Board #174 May 29, 3:30 PM - 5:00 PM

Dynamic Stretching On 5-km Performance And Running Economy In Collegiate Cross-country Runners

Adriane Wunderlich1, Susan W. Yeargin2, Jacob Wilson3, James D. Kingsley1. 1Indiana State University, Terre Haute, IN. 2University of South Carolina, Columbia, SC. 3University of Tampa, Tampa, FL. (Sponsor: Alvaro N. Gurovich, FACSM)

(No relationships reported)

Dynamic stretching may not cause significant increases in hamstring flexibility. Therefore it may not cause a decrease in performance, as has been reported after static stretching. Furthermore, runners with stiffer hamstrings may have a higher running economy (RE) than more flexible runners. However, the effect of dynamic stretching on RE and running performance are currently unknown.

PURPOSE: To investigate the effects of dynamic stretching on RE and 5-km time trial (5kTT) compared to a control protocol in collegiate cross-country runners.

METHODS: Fifteen male cross-country runners (Age: 20 ± 1 yrs; Ht: 1.76 ± 0.06 m; Wt: 68.9 ± 6.4 kg; Body fat: 7.8 ± 2.3%; VO2max 58.1 ± 3.9 ml/kg/min) completed a random crossover design that included a half-mile warm-up run at 65% VO2max followed by either dynamic stretching or control protocol. The 15 minutes of dynamic stretching consisted of 8 different lower-body dynamic stretches that were repeated twice. The 15-minute control protocol consisted of quite rest. After each protocol, participants completed a 5kTT for evaluation of RE, via indirect calorimetry, and time. Sit-and-reach scores were recorded both before and after each protocol. RE was measured as the total calories expended during 5kTT and time was also recorded. A repeated measures ANOVA was used to examine a condition (control protocol vs. dynamic stretching) by time (pre vs. post protocol) interaction on the sit-and-reach score. RE, and 5-km performance time were examined using a one-way ANOVA across conditions.

RESULTS: There was no significant interaction or main effects for the sit-and-reach test. RE was not statistically different between conditions (Dynamic: 234 ± 26 kcals; Control: 239 ± 25 kcals; p>0.05). There was a significant difference found among 5kTT between conditions (Dynamic: 18.0 ± 0.9 minutes; Control: 18.4 ± 0.9 minutes; p<0.05).

CONCLUSION: These findings suggest that dynamic stretching does not increase hamstring flexibility nor affect RE but does increase performance time in NCAA male distance runners. Further investigations are needed to elucidate the physiological alterations that occur after static stretching.

This study was funded by the Graduate and Professional

Studies Graduate Fund at Indiana State University.

699 Board #175 May 29, 3:30 PM - 5:00 PM

Manipulation of Training Regiment and Dietary Pattern Enhanced Submaximal Performance in Ramadan Fasting Distance Runners

Ali M. Al-Nawaiseh, Mo’ath F. Bataineh. Hashemite University, Zarqa, Jordan. (Sponsor: Mathew James Green, FACSM)

(No relationships reported)

Muslim athletes are obligated to abstain from eating and drinking from dawn to dusk during the whole lunar month of Ramadan, this religious practice has been reported by many to interrupt regular training schedules and therefore influence performance.

PURPOSE: We investigated the effects of modified training protocols and altered dietary intake on the performance of Ramadan (daytime) fasting on distance runners.

METHODS: Fourteen competitive distance male runners (23.9 ± 3.1 yrs) who observed Ramadan participated in this study after signing an IRB-approved Informed consent. Participants reported to the lab at 10:00 am and rested for 30 minutes. A graded treadmill exercise protocol (Conconi) was conducted to assess oxygen consumption (VO2), rating of perceived exertion (RPE), heart rate (HR), and time to exhaustion on 3 separate occasions (3 days before Ramadan, at day 14 and day 28 of Ramadan).Subjects maintained their free living style for the first two weeks of Ramadan. For the second half of Ramadan participants were randomly divided into two groups (control and treatment). Treatment included training (modified schedule & increased load) and dietary (increased caloric and fluid intake and modified timing of intake)

RESULTS: Ramadan decreased energy intake (p < 0.0001), number of meals (p < 0.0001), and training loads (p < 0.0001). HR and VO2 at sub maximal speeds tended to decrease while RPE increased (p = 0.046) during Ramadan. Time to exhaustion tended to increase during Ramadan for both groups. However, the treatment group took longer to reach exhaustion (p = 0.021) and tended to have lower HR and VO2 compared to control group at the end of Ramadan. Body weight and body fluids were not affected by fasting.

CONCLUSIONS:Ramadan enhanced performance and this effect could be augmented by manipulation of dietary behavior and training protocol.

700 Board #176 May 29, 3:30 PM - 5:00 PM

Maximal Oxygen Deficit And Race Performance In Portuguese Elite Middle Distance Runners

Francisco Alves1, Bernardo Manuel1, Victor Reis2, Joana Reis1, Veronica Vleck1. 1Technical University of Lisbon - Faculty Human Kinetics, Lisbon, Portugal. 2University of Trás-os-Montes e Alto Douro, Vila Real, Portugal.

(No relationships reported)

PURPOSE: Middle distance performance in running is dependent on the ability of deriving high amounts of muscle power from both the aerobic and the anaerobic metabolic energy systems. The purpose of this study was to verify the association between the 1500 m performance and the anaerobic capacity measured by the maximal accumulated oxygen deficit (MAOD) method.

METHODS: 28 national and international level Portuguese runners were assigned to two groups according to season best time (SBT), ELIT (N=13; 26.2 ± 4.0 yr.; 66.1 ±4.2 kg; 1.79 ± 0.06m; 3:41,00 ± 5,38 min:s) and SUBELIT (N=15; 22.0 ± 3.7 yr.; 62.8 ± 7.4 kg; 1.76 ± 0.08 m; 3:41,00 ± 5,38 min:s). Every runner completed an incremental track test of 5 × 6 min duration and constant velocity steps, in order to establish the submaximal energy cost of running, and also the VO2peak and maximal aerobic velocity (MAV) and a supramaximal track test of 600 m for the estimation of MAOD. Respiratory data was collected breath by breath (K4b2, Cosmed, Italy).

RESULTS: MAOD was significant lower in ELIT than in SUBELIT athletes (29.32 ± 14.84 ml.kg-1 and 99.76 ± 9.72 ml.kg-1, respectively, p= 0.04), contrarily to MAV (6.11 ± 0.53 ms-1 and 5.76 ± 0.34 ms-1; p = 0.05) and the VO2peak that did not differ between groups. Estimated aerobic contribution during the 600 m supramaximal track run was 72.92 ± 12.02 % for the ELIT and of only 65.34 ± 6.23 % for the SUBELIT runners. However, submaximal running economy was similar in both groups. When the total group was considered, MAV showed to be the best predictor of 1500 m run performance (r2= 0.26).

CONCLUSIONS: Best 1500 m Portuguese runners, in spite of a good international competitive level, have a markedly aerobic profile, lacking muscle power and sprint adaptations.

701 Board #177 May 29, 3:30 PM - 5:00 PM

Resting Gene Expression Relationships With 40K Time Trial Performance

Timothy A. VanHaitsma, Alan R. Light, Kathleen C. Light, Ronald W. Hughen, Hannah M. Aizad, Andrea T. White, FACSM. University of Utah, Salt Lake City, UT.

(No relationships reported)

PURPOSE: Performance prediction has long been a goal of coaches and scientists. Ventilatory threshold and VO2max are two methods that have been used with varying success. Gene expression may be a novel method for performance prediction. The purpose of this study was to evaluate the predictive value of baseline leukocyte gene expression in receptors related to fatigue and energy metabolism for predicting 40k time trial performance compared to prediction equations using ventilatory threshold (VT).

METHODS: Twenty cyclists (36.1 ± 9.7 yr, 54.8 ± 5.9 mL/kg/min) performed a graded maximal exercise test to determine VO2max and VT and a 40k time trial (TT) one week later. A venous blood sample was obtained before TT. Leukocytes were manually separated for RNA extraction and quantitative real-time polymerase chain reaction (qPCR) analysis was performed on: 4 metabolite-detecting genes (acid-sensing, ASIC3; purinergic 2X sensing, P2X4; and 2 transient vanilloid receptors, TRPV1 and TRPV4); 2 indolamine receptors (dopamine, DRD4; and serotonin, HTR1D); 3 immune markers (IL-10, IL-6 and Toll-like receptor 4, TLR4); 4 transcription factors (cyclic AMP responsive element binding protein 1, CREB1; peroxisome proliferator-activated receptor alpha ,PPARα; 5’-AMP-activated protein subunit beta 1,PRKAβ1; Sirtuin 1, SIRT1); and 4 other genes (ryanodine receptor 1, RYR1; vascular endothelial growth factor A, VEGFA; superoxide dismutase 2, SOD2; glucocorticoid receptor, NR3C1. Individual regressions were run comparing each receptor with average power output for the 40k time trial.

RESULTS: VT was significantly correlated with TT average power output (r = .670, p < .001) while VO2max was not correlated with power output (r = .153, p = .260). Several individual receptors correlated with TT power output including NR3C1 (r = .567, p < .05), PPARA (r = .526, p < .05), and SIRT1 (r = .706, p< .05).

DISCUSSION: The receptors that best correlated with performance all are associated with increased metabolism and reduced inflammation. PPARA and SIRT1, in particular, are transcription genes that regulate many downstream receptors that control multiple aspects of exercise performance. Thus, expression of certain genes approaches VT in providing a useful, non-exercise based method for predicting exercise performance.

702 Board #178 May 29, 3:30 PM - 5:00 PM

Is Standing Broad Jump Performance Related To Running Economy Or Marathon Finishing Time?

James M. Smoliga1, Kaleen M. Lavin2, Allison M. Straub2, Gerald S. Zavorsky2. 1High Point University, High Point, NC. 2Marywood University, Scranton, PA.

(No relationships reported)

Plyometric training has been shown to concurrently improve muscular power and running economy (RE), however, there is limited data regarding how muscular power, as measured by a standing broad jump, is related to RE and marathon performance.

PURPOSE: To determine the relationship between RE, marathon finishing time (MFT), and standing broad jump performance.

METHODS: A heterogeneous group of 28 runners (10 females, 18 males) performed standing broad jumps using their left leg only (L), right leg only (R), and both legs (B), one to four weeks before a marathon (PRE) and 15 minutes after completion of a marathon (POST). Jump distance was normalized to height and the difference (DIFF) between POST and PRE jump distance was computed. Additionally, during PRE, RE was measured at three sub-maximal treadmill running speeds. Pearson product-moment correlations were computed to relate jumping parameters, RE, and MFT separately for males and females.

RESULTS: RE was not significantly correlated to MFT in females or males. There were no significant relationships between RE or MFT with any of the PRE jump parameters for either sex. A significant correlation between MFT and LDIFF (r = -0.71, p = 0.03) and RDIFF (r = -0.75, p = 0.02) was seen in females. In males, there was a significant correlation between MFT and BDIFF (r = -0.59, p = 0.02).

CONCLUSIONS: A pre-race standing broad jump is a poor predictor of RE and MFT, however a moderate to strong relationship exists between MFT and post-race change in standing broad jump performance. It is possible that individuals with greater post-race broad jump changes may have had greater neuromuscular fatigue or muscle damage in their fast twitch muscle fibers from running at a higher intensity. Thus, future research should determine the causes of post-race broad jump changes and whether this is indicative of muscle damage, or whether this can predict the time course for recovery following a marathon. Additionally, inconsistencies between females and males suggests either sex-specific differences exist in the relationship between broad jump and marathon performance, or the observed relationship is an artifact of the heterogeneous sample used. Future research should search for more valid field tests which relate to RE and marathon performance.

703 Board #179 May 29, 3:30 PM - 5:00 PM

Submaximal Test to Monitor the Training Response of Endurance Runners

Valorie Parker, Richard Robinson. University of Indianapolis, Indianapolis, IN.

(No relationships reported)

PURPOSE:Overtraining is a problem for endurance runners and there is a need for a valid, reliable, and practical test to monitor the training response.The purpose of the study was to develop a noninvasive, submaximal test for endurance runners similar to Lamberts et al. (2011) test for endurance cyclists.

METHODS:Five (n=3 males, n=2 females) intercollegiate cross country runners (age 19.8 yrs +/- 1.3, bodyweight 65.32 kg +/- 7.08, height 1.76 m +/- 0.14) completed eight weekly treadmill tests in which they ran continuously for 4 minutes at both 60% and 80% of their estimated maximum heart rate and 3 minutes at 90%. Running velocity (m/s), RPE (Borg 6-20), and stride length were measured at each stage and heart rate recovery was measured posttest (60 sec.). Daily training load was the product of workout duration and RPE (Foster 0-10) with the sum of weekly workouts equaling training load. Training load was correlated with the test variables to determine significant relationships (p < .05) and intraclass correlations were calculated to determine reliability of the test variables.

RESULTS:Training load had a significant negative correlation with stride length (r= -.719, p=.044) at 60% of maximum heart rate and significant positive correlations with velocity at 80% (r=.753, p=.031), velocity at 90% (r=.911, p=.002), stride length at 80% (r=.837, p=.009), stride length at 90% (r=.888, p=.003), and RPE at 90% (r=.814, p=.014). ICC’s ranged from 0.858 to 0.985 for nine of the ten test variables with heart rate recovery demonstrating an intraclass coefficient of .686.

CONCLUSIONS:Stride length at 60% of maximum heart rate and RPE at 90% demonstrated the expected relationship with training load and nine of the ten test variables demonstrated acceptable levels of reliability.

704 Board #180 May 29, 3:30 PM - 5:00 PM

Can Accelerometry-Based Physical Activity Monitors Accurately Estimate Exercise Intensity and Running Economy in Athletes?

Joshua J. Fleming1, James M. Smoliga2, Andrea J. Fradkin, FACSM1. 1Bloomsburg University of Pennsylvania, Bloomsburg, PA. 2High Point University, High Point, NC.

(No relationships reported)

Accelerometry-based physical activity monitors have been shown to be a valid estimator of exercise intensity across a range of activities. However, limited research has been conducted in their ability to quantify exercise intensity in an athletic population.

PURPOSE: To determine relationships between accelerometer data, exercise intensity, and running economy (RE) across multiple intensities in recreational runners.

METHODS: Ten recreationally active college-age students (6 males, 4 females) ran for five minutes on a treadmill at three sub-maximal intensities with three minutes rest between each speed. Treadmill speeds were determined using individual training history and were assigned to closely correspond to easy training pace, marathon pace, and 10km race pace. The volume of oxygen consumption (VO2) was continuously measured using a metabolic cart. RE was quantified for each speed as VO2 to travel 1km. Total activity counts were continuously recorded with an accelerometer and the Crouter equation was used to estimate exercise intensity. A repeated measures ANOVA determined differences in metabolic and accelerometry variables across speeds using data from the last 90 seconds of each speed. Pearson product moment correlations determined relationships between measured and accelerometer-estimated exercise intensities, as well as between accelerometer counts and RE.

RESULTS: There were significant differences in measured VO2 (p ≤ 0.001) but not RE (p = 0.717) between speeds. Accelerometer counts (p = 0.364) and estimated exercise intensities (p = 0.372) did not significantly differ between speeds. There were no significant correlations between measured and estimated exercise intensities or between accelerometer counts and RE at any speed.

CONCLUSIONS: While measured VO2 increased at faster speeds, counts recorded on the accelerometer remained unchanged resulting in inaccurate estimations of exercise intensities. This suggests acceleration of the body’s center of mass does not vary across running speeds in recreational athletes. Although RE and accelerometry data remained stable across speeds, they were not related. Thus, it seems accelerometry-based physical activity monitors are not a valid method to estimate exercise intensity or RE across different running speeds in athletes.

705 Board #181 May 29, 3:30 PM - 5:00 PM

Heart Rate Pacing vs. Running by Feel During an Ironman Triathlon

William M. Adams, Tracy L. Hicks, Douglas J. Casa, FACSM, Rebecca L. Stearns, Luke N. Belval, Brent C. Creighton, Robert A. Huggins, J. Luke Pryor. University of Connecticut, Storrs, CT.

(No relationships reported)

PURPOSE: To examine pacing differences in triathletes who race with and without heart rate during the bike and run portion of an Ironman triathlon.

METHODS: Subjects (n=37; 30 males, 7 females, Mean±SD; age=39±7y, height=174.0±9.9cm, weight=72.0±10.0kg, body fat=15.3±5.6%) participating in the 2012 Lake Placid Ironman volunteered for this study. Subjects were divided into two groups, athletes who monitor heart rate while racing (HR; n=17) and athletes who do not (NHR; n=20). Subjects’ heart rate and pace were monitored using a GPS watch and compared during four periods of the race; 1st bike loop (BL1), 2nd bike loop (BL2), 1st run loop (RL1), and 2nd run loop (RL2). Pre & post race urine specific gravity (USG) and percent body mass loss were used to measure hydration status.

RESULTS: Finish time for HR and NHR were 803.3±93.9min and 777.5±68.8min (p>0.05) respectively. Average post race gastrointestinal temperature (Tgi) was (38.31±1.00°C, 38.38±0.55°C, p>0.05) for HR and NHR groups respectively. Average percent body mass loss, pre- and post-race USG were 3.18±1.62%, 1.015±0.009, 1.025±0.007, respectively. Results demonstrated a significant main effect of time for heart rate for all loops (p=0.001). No significant differences in average heart rate between HR and NHR were observed for all loops (p=0.942). Pace for BL1 and BL2 was not significantly different between HR and NHR groups (p=0.254), however a significant main effect of time occurred between BL1 and BL2 (p=0.007). Pace for RL1 and RL2 was not significantly different between HR and NHR groups (p=0.630). RL1 and RL2 showed a significant effect of pace over time (p<0.001). All loops (BL1, BL2, RL1 and RL2) produced a significant overall time effect for pace (p<0.001), but were not significant between HR and NHR (p=0.661).

CONCLUSIONS: Although there was an overall effect for pace between loops for the bike and run portions of the competition, no differences in pace occurred between HR and NHR groups, despite similar measures of hydration status, finish time and finishing gastro-intestinal temperature (Tgi). Pacing via HR did not result in different pacing than those who relied on self-perceived exertion during competition.

706 Board #182 May 29, 3:30 PM - 5:00 PM

Effect of Training in Minimalist Running Shoes on Running Economy

Kurt Van Wagenen, Brenda Benson, A. Wayne Johnson, Ulrike Mitchell, Iain Hunter, Sarah Ridge. Brigham Young University, Provo, UT.

(No relationships reported)

PURPOSE: The popularity of running in minimalist shoes raises questions about their effect on running economy (RE) as compared to running in traditional running shoes. It has been suggested that minimalist shoes allow for better metabolic economy during running. This study assessed whether or not RE was significantly different between groups training in traditional (Trad) running shoes and transitioning to minimalist (Min) shoes before and after 10 weeks of running.

METHODS: Twenty five runners who had been running a minimum of 15 miles per week with no previous training in minimalist running shoes participated in this study. Subjects were randomly assigned to either the control group, which ran in traditional running shoes, or the minimalist group, which transitioned to minimalist shoes over 10 weeks. All subjects performed sub-maximal VO2 tests in both traditional and minimalist running shoes before and after the 10 week training period. The order of testing conditions was randomized, with the first condition lasting 6 minutes and the second condition lasting 3 minutes. The treadmill pace was based on the subject’s 5K or 10K pace and held constant throughout the duration of the testing sessions. Average VO2 data over the last minute of running in each condition was analyzed using a 2-way repeated measures ANOVA with statistical significance set at p<.05.

RESULTS: There were no significant differences in RE between groups during either of the running conditions during pre- or post-testing (p=.159). There was a significant difference in RE between pre and post-testing in both shoe conditions (MinVO2pre=42.7±1.3, MinVO2post=39.9±1.1; TradVO2pre=42.3±1.4, TradVO2post=39.1±1.0; p=.01), regardless of group. However, the difference between both groups’ RE improvement was not statistically significant for either shoe condition (p=.196).

CONCLUSIONS: Overall, RE improved for both training groups, however there was no significant difference in the improvement of RE between groups in either shoe condition. Improvements in RE may have been caused by more consistent training as a result of participation in this study. In addition, the sub-maximal test may have allowed for more variability in individual intensities, and therefore, may not be as sensitive as VO2max testing in assessing changes in RE specific to shoe type.

707 Board #183 May 29, 3:30 PM - 5:00 PM

Comparison Of Two Endurance Training Models In Amateur Runners

Carles Tur Carbonell1, Jordi Ferré2, Carlos González-Haro1. 1School of Medicine, University of Zaragoza, Zaragoza, Spain., Barcelona, Spain. 2Research Institute for Sport & Exercise Sciences, University of Liverpool John Moores, Liverpool, United Kingdom.

(No relationships reported)

Introduction: Polarized training (PT) is characterized by high intensity stimulus whereas threshold training (TT) is described at lower intensity stimulus.

PURPOSE: Compare the effect of two type of cross trainings following PT or TT on the maximal aerobic velocity (VAM).

METHODS: 10 amateur Spanish runners (9 males, 1 female; Age: 35 ± 2 yrs, height: 1.78 ± 0.02 cms, weight: 70.8 ± 1.69 kg, BMI: 22.26 ± 0.33 kg·m-2, and experience: 5 ± 2 yrs) carried out two VAM test each season, as proposed by Léger-Boucher and described elsewhere, pre and post training intervention (TI) during two consecutive seasons. TI in season one (TI1) consisted of 3 to 5 sessions of 77 % of Aerobic 1 (A1) < 65 % VAM, 20 % of Aerobic 2 (A2) 65 - 85 % VAM, 3 % of Aerobic 3 (A3) >85 % VAM , total absolute volume = 355 kms, and resistance strength training (2 sessions of 2 sets of 32 ± 18 reps · week-1 at 50 ± 15 % of 1 RM). TI in season two (TI2) consisted of 3 to 5 sessions of 76 % of A1, 7 % A2, 17 % A3, total absolute volume = 369 kms, and maximal strength training ( 2 sessions of 3 sets of 8 ± 4 reps · week-1 at 80 ± 5 % of 1 RM). Pre TI1 and TI2 VAM was assessed 4 weeks after the beginning of the season and Post TI1 and TI2 VAM was evaluated after 8 weeks of TI. VAM test was performed in a standardized recovery week. Paired samples t-test was used and significance differences was set at P<0.05.

RESULTS: Pre TI1 VAM was 50.80 ± 5.23, 14.81 ± 1.48 and Post TI1 VAM was 54.20 ± 5.24, 15.77 ± 1.46 (P<0.001); Pre TI2 VAM was 54.29 ± 6.02, 15.79 ± 1.68 and Post TI2 VAM was 57.71 ± 5.40, 16.75 ± 1.49 (P<0.01), ml·kg·min-1 , Km·h-1 , respectively. Also Pre TI1 to Pre TI2 and Post TI1 to Post TI2 were statistical significant (p<0.001). A2 TI1 was 8.75 ± 4.40 and A2 TI2 was 3.31 ± 1.28 (P<0.01) and A3 TI1 was 1.50 ± 1.58 and A3 TI3 was 7.81 ± 3.95 (P<0.001) Km · Week-1 respectively.

CONCLUSION: These results show that either PT or TT have a positive impact in VAM after TI. Despite of no differences were found between the two TI, Pre and Post TI2 were significantly higher than Pre and Post TI1 suggesting that in already trained athletes PT could have a major impact in VAM.

708 Board #184 May 29, 3:30 PM - 5:00 PM

The Effect of Cold Water Immersion on Repetitive 1600m Run Performances in College Aged Distance Runners

Michael J. Ryan, Jobey Knapton, Paul Reneau. Fairmont State University, Fairmont, WV.

(No relationships reported)

PURPOSE: This study aimed to test the effectiveness of lower body cold water immersion (CWI) to assist recovery in repetitive maximal 1600m run performances.

METHODS: Male and Female runners aged 19.6 ± 1.3 (n=22) were asked to perform two maximal 1600m time trials on a 400m track. Conditions were setup to mimic a track & field competition where the athlete might have to run multiple races in the same day. All athletes ran a minimal of 49 km per week (∼30 miles) for the eight weeks prior to testing. Athletes were allowed to perform their normal warm-up and males and females raced in separate trials. After the trials all participants performed a cool down jog for 15mins then the control group sat in chair for 12 mins and the experimental group stood in a cold water tank (15.5°C or 60°F) that covered about the length of the thigh for 12 mins. Caloric intake between trials was matched to participant’s body weight (8-10kcal/kg). After feeding subjects had a two hour recovery period before they returned to the track to warm-up and perform the second time trial. Time and RPE rating were recorded after each trial.

RESULTS: The average difference in time between trial 1 and trial 2 increased 2.18 ± 4.84 sec within the control group and decreased 1.36 ± 5.73 sec in the CWI group. Though this failed to reach significance (p=0.052) there was a trend that indicated the CWI had an overall positive effect on the second time trial performance. Furthermore, within the CWI group 7 out of 11 participants improved performance on the second time trial whereas within the control group 8 out 11 participants decreased performance on the second time trial. Every participant indicated a score of 20 on the Borg RPE Scale after each trial run.

CONCLUSIONS: Even though CWI failed to reach a statistical difference (p≤0.05), the use CWI may aid short-term recovery and improve performance during competitions that required repetitive performances.

709 Board #185 May 29, 3:30 PM - 5:00 PM

High Bike Placing Results In Poorer Run and Overall Finish in Ironman® Triathlon

Anton K.O. Stocker, Christopher W. Herman, Stephen J. McGregor. Eastern Michigan University, Ypsilanti, MI.

(No relationships reported)

PURPOSE: To use large sample size race datasets to test the hypothesis that strong bike performances result in poorer run performance and overall poorer finish in Ironman® triathlon.

METHODS: Participant demographic information, overall summary performance data, and intra-race split data were collected for 29 North American Ironman® triathlon events between 2002 and 2008 using online publicly available sources. Perl scripts were used to retrieve data from the online sources (www.perl.org), and SQL and Perl scripts were used to import and update data into a SQL database (MySQL Server 5.1.57 and MySQL Client 5.5.19; Oracle Corp., Redwood City, CA). Participants were ranked in all elements of the race, by division and overall finish. Data for mean divisional participation with n > 100, and male and female professional divisions were collected and ranked. Top 50 performances Overall (n=14,437, OA), for Run (n=14,439, R), Bike (n=13,956, B), and Swim (S) from each event resulted in a total dataset of 42,832 samples. Competitor rankings at the end of each discipline and rank changes between disciplines were calculated for Swim-Bike Delta (SBD), Bike-Run Delta (BRD), as well as difference between discipline and overall rank Bike-Overall Delta (BOAD) and Run-Overall Delta (ROAD). MANOVAs were performed using IBM SPSS 19.0 (Chicago, IL), α=0.05.

RESULTS: On average, R finished higher than B in final placing (29.3±0.2 vs 30.0±0.2, p<0.001). SBD was greatest for B (25.21±0.4) and significantly greater for OA than R (16.7±0.3 and 16.52±0.4, p<0.001). B lost places on the run (BRD = -16.7±0.3) while R gained (18.1±0.3) and OA gained slightly, but significantly (2.1±0.2), p<0.001 for all. Relative to their final placing, B performed better on the bike and poorer on the run (BOAD = -5.2±-.2, ROAD = 11.52±0.2, p<0.001) and R performed poorer on the bike and better on the run (BOAD = 13.4±0.2, ROAD = -4.7±0.2, p<0.001) while OA performed better than both bike and the run (BOAD = 6.5±0.1, ROAD = 4.4±0.1, p<0.001).

CONCLUSION: These data indicate that strong cyclists lose more places than strong runners gain on the run in Ironman® triathlons. Additionally, the top 50 overall finishers are more consistent across disciplines. This objective, large scale study should help triathletes prepare for optimal performance in Ironman® triathlon events.

© 2013 American College of Sports Medicine

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