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Medicine & Science in Sports & Exercise:
doi: 10.1249/01.mss.0000417526.38002.a4
Abstracts

Abst A-FreeCommSlides

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A-25 Free Communication/Slide - Physical Activity Behavior Change Strategies

MAY 30, 2012 9:30 AM - 11:30 AM

ROOM: 2020

582 Chair: Nathaniel Thom. SAIC, San Diego, CA.

(No relationships reported)

583 MAY 30 9:30 AM - 9:45 AM

Does Self Efficacy Predict Intervention Modality Preferences in Overweight Individuals? Results from the REACT Study

Robert Powell1, Miriam Seidel1, Gretchen Piatt2. 1University of Pittsburgh Diabetes Institute, Pittsburgh, PA. 2University of Michigan, Ann Arbor, MI.

(No relationships reported)

INTRODUCTION: Heightened self-efficacy is correlated with greater success toward the adoption and maintenance of healthy lifestyle behaviors like exercise and eating. Moreover, self-efficacy is associated with self-regulated learning strategies, such as type of learning environment. However, it is undetermined whether self-efficacy is associated with selection of a specific modality of lifestyle intervention.

PURPOSE: To determine if self-efficacy of exercise and eating is associated with selection of intervention modality in participants from the Rethinking Eating and ACTivity Study (REACT).

METHODS: Participants were screened for BMI ≥ 25 kg/m2 and waist circumference (WC) (> 35 inches in women and > 40 inches in men) in 8 rural, underserved communities in southwestern, Pennsylvania. Eligible participants were assigned to 4 Group Lifestyle Balance intervention groups: Face to Face (FF) (n=119), DVD (n=113), internet (INT) (n=101), and self-selection (SS) (n=101). Participants in SS were empowered to select the modality of their choosing (60% chose FF, 40% INT, 0% DVD). Self-efficacy was measured using the 9 item Self Efficacy for Exercise questionnaire (SEE) and the 20 item Weight Efficacy Lifestyle questionnaire (WEL). Each questionnaire uses a 0-10 point likert scale.

RESULTS: These analyses focus on the SS group. 101 participants were enrolled in SS (75% female, 96% Caucasian, mean age 52 ± 12.7). Baseline weight, BMI and WC were 209.9 lbs ± 39.2; 35 kg/m2 ± 5.7; and 43.5 ± 5.4 inches, respectively. Mean baseline self-efficacy scores were 6.76 ± 2.37 for SEE and 6.78 ± 1.77 for WEL. Those who chose FF had significantly greater baseline WEL scores compared to those choosing INT (7.2 vs. 6.2, p< 0.01). After adjusting for age, gender and income, a significant association remained between WEL scores and FF modality choice (p=.005), but not SEE scores and modality choice (FF= 6.9 vs. INT = 6.6, p=0.55).

CONCLUSION: These data indicate that heightened self-efficacy for eating is associated with choosing a face to face lifestyle intervention in overweight/ obese individuals. Perhaps assessing self-efficacy, prior to enrollment, may aid in tailoring interventions to meet participant needs. Future analysis will assess additional factors to help determine modality preferences.

584 MAY 30 9:45 AM - 10:00 AM

The Effects of a Self-Determination Theory Based Exercise Intervention in Sedentary Overweight or Obese Women

Ya-Ting Hsu, Janet Buckworth, FACSM, Brian Focht, FACSM, Ann A. O’Connell. The Ohio State University, Columbus, OH.

(No relationships reported)

Women are more likely to be physically inactive and overweight, and thus, we need an effective theory-based approach to help sedentary overweight/obese women adopt and maintain regular exercise.

PURPOSE: (1) Examine effects of a Self-Determination Theory (SDT)-based exercise intervention (SD) compared to an exercise-only group (EX) on physical activity (PA), physical variables, SDT-based variables, self-regulation, self-efficacy (SE) and quality of life, (2) investigate the relationship between the psychological variables and PA, and (3) identify the influential predictors of PA adherence.

METHODS: Project CHANGE (to being a Confident, Healthy, And Goal-directed Exerciser) was a randomized control trial with 8-week PA intervention plus 4-week follow-up. The SD group received SDT-based exercise and behavioral intervention and the EX group only received traditional exercise training. Evaluations were conducted at baseline, pre/post, and follow-up. The final sample size was 21 (NSD = 11; NEX = 10).

RESULTS: Weekly PA did not differ significantly between the groups at post-intervention when baseline PA was controlled (p = .947). However, the majority (70%) of the SD participants (vs. 27.3% EX) remained active at the follow-up and met the public health PA recommendation (χ2 (1) = 3.834, p = .05). For both groups, integrated regulation (p = .005), perceived autonomy support (p = .015), and goal-setting (p = .001) significantly increased over time. Scheduling SE (p = .023) was significantly higher in the SD group, regardless of time.

Regardless of treatment group, exercise adherents (defined as exercising greater or equal to 150 min/week at the 4-week follow-up) had significantly greater intrinsic motivation (p = .041), integrated regulation (p = .003), identified regulation (p = .008), scheduling (p < .001) and coping SE (p = .037), and goal-setting (p < .001) and planning (p < .001) than non-adherents. Confidence and ability to self-regulate were important for exercise adherence. Goal-setting was the most influential predictor among these variables.

CONCLUSION: The results warrant additional testing of Project CHANGE as a method to help overweight/obese women start and maintain PA. A higher fidelity SDT intervention with larger sample size is necessary to examine the treatment effect.

585 MAY 30 10:00 AM - 10:15 AM

The Emotional Responses of Older Adults to Physical Activity Promoting Technology

Kyungo Kim, Blake Lindley, Leticia Malavasi, Andiara Schwingel, Wojtek Chodko-Zajko, FACSM. University of Illinois at Urbana-Champaign, Urbana, IL.

(No relationships reported)

Understanding the perceptions and emotions of older adults when they encounter new technology is important. Although learning to use and adopt new technology can often provide a significant benefit, many older adults decline to adopt new technologies due to feelings of anxiety and discomfort they experience when exposed to unfamiliar items.

PURPOSE: This study was designed to explore the perceptual and emotional reactions of four older adults to a number of commercially available products.

METHODS: Participants were invited to examine four devices, two TV remote controls and two commercially available step counters. For both the TV remotes and the step counters, a very simple and a very complex version of each type of item were provided. Participants were invited to inspect each item carefully and then participate in a 60-90 minute semi-structured interview. All interviews were transcribed and analyzed.

RESULTS: Three dominant themes emerged from data; (1a) It is easy, this is for me, (1b) It is too difficult, (2) I am smart, I can figure it out, and (3) I do not need this: Why should I care? Themes 1a and 1b confirm that older adults often gravitate towards simple and familiar version of technology. Themes 2 and 3 provide evidence of a more nuanced perspective. Some seniors have high levels of self-efficacy and believe themselves to be capable of using and understanding new technology but they do not always see the need to change.

CONCLUSION: Perceived complexity, perceived benefit, exposure frequency, previous experience, education level, and socio-economic status were factors that appeared to differentiate between older adults who were likely to be ‘early adopters” and those who were not. Technology design and interface, and appropriate technological education as also emerged as factors that might influence older adults’ inclination toward technology. Our findings contribute to our understanding of the complexities underlying older adult’s emotional responses to new technology.

586 MAY 30 10:15 AM - 10:30 AM

(S)Partners For Heart Health: A School- And Web-based Nutrition And Physical Activity Intervention

Joseph J. Carlson1, Joey C. Eisenmann2, Karin A. Pfeiffer, FACSM1, Kimbo yee1, Stacey LaDrig1, Darijan Suton1, Natalie Stein1, David Solomon1, yolanda Coil1. 1Michigan State University, East Lansing, MI. 2Helen Devos Children’s Hospital, Grand Rapids, MI.

(No relationships reported)

PURPOSE: Evaluate the effectiveness of a school- and web-based intervention on nutrition and PA behaviors and CVD risk factor status.

METHODS: Non-randomized pilot study of 181 5th grade students (104 girls and 77 boys) participating in the (S)Partner intervention (n=86) or comparison schools (n=95) from fall 2008-spring 2009. Both groups received an 8 lesson nutrition and PA curriculum during physical education (PE), while the (S)Partner students also received web-based goal setting and mentoring by college students. Baseline and 6 month assessments included a food frequency questionnaire (FFQ), a curriculum based nutrition and PA behavior survey, and frequency and duration of moderate-to- vigorous (MVPA), and screen time (ST). CVD risk factors included anthropometrics, blood pressure (BP), blood lipids, C- reactive protein (CRP) and estimated VO2max via the Progressive Aerobic Cardiovascular Endurance Run (PACER).

RESULTS: At baseline, 73% and 66% of children did not meet MVPA recommendations (mean ± SD=4.5 ± 2.1 d/wk) and ST (3.3± 2.5hrs/d) respectively. However the PACER scores indicated that 86% were aerobically fit. The FFQ revealed a low nutrient density with 50-99% not meeting food group or nutrient targets. The % not meeting CVD risk factor targets included: overweight or obese 38%; dyslipidemia 30%; CRP 7%; and BP 6%. The pre-post evaluation revealed modest nutrition improvements favoring the (S)Partners including a 0.3 serving whole grain increase (p=0.02), and trends for a 2 g fiber (p=0.13) and 400 mg K+ (p=0.10) increase. The nutrition and PA survey indicated both groups improved, with between group effects favoring the (S)Partners (composite p ≤ 0.002). There were no group differences in MVPA, ST or the PACER. CVD risk factors changes included a 7% TC decrease in the comparison (p ≤ 0.001) and a 4% HDL increase in the (S)Partners group (p≤0.01).

CONCLUSIONS: Compared to a standard PE curriculum, the (S)Partner intervention produced modest improvements in nutrition behaviors. PA and CVD risk factors changed minimally in both groups. Based on this initial pilot and focus groups, areas identified to increase the % of children adhering to nutrition and PA behaviors to improve CV health status included: enhancing the web-based communication, adding incentives, and increasing parental involvement.

587 MAY 30 10:30 AM - 10:45 AM

Physical Activity And Change In Health-related Quality Of Life In Older, Knee Osteoarthritis Patients

Alexander R. Lucas, Brian C. Focht, FACSM, Matthew J. Garver, Steven T. Devor, FACSM, Kevin Hackshaw, Justin Dials, Charles F. Emery. The Ohio State University, Columbus, OH.

(No relationships reported)

Physical activity (PA) interventions consistently result in improvements in health-related quality of life (HRQL) among older, knee osteoarthritis (KOA) patients. However, the HRQL benefits accompanying PA have been shown to dissipate during post-treatment follow-up periods and recent evidence suggests the deterioration in the effect of PA on HRQL may be related to failure to maintain regular PA participation.

PURPOSE: The purpose of the single blind, randomized controlled IMPACT pilot trial was to examine the comparable efficacy of traditional exercise training (TRAD) and a group-mediated cognitive-behavioral exercise intervention (GMCB) for improving HRQL and physical activity participation in older, KOA patients.

METHODS: A total of 80 KOA patients (M age = 64 years) were randomly assigned to the GMCB (n = 40) or the TRAD (n = 40) interventions. Assessments of HRQL were obtained at baseline, 3 months and 12 months using the Physical (PHS) and Mental Health Summary (MHS) Scales of the RAND SF-36.

RESULTS: Results of an intention to treat analysis involving a 2 (Treatment) × 3 (Time) ANCOVA controlling for age yielded a significant Treatment × Time interaction (p<0.05) for the PHS. No significant main effects or interactions were observed for the MHS (p > .05). Post hoc analysis revealed that while both the GMCB (Cohen’s d = .86) and TRAD (d = .59) interventions resulted in significant improvements in the PHS at 3 months, the increase in PHS was only maintained within the GMCB intervention at 12 month follow up (d = .79). Partial correlation analyses also revealed that accelerometer-determined minutes PA was significantly correlated with the PHS (r = .42; p < .01) at 12 month follow-up.

CONCLUSIONS: These findings suggest that a GMCB exercise intervention, designed to promote PA adherence, resulted in superior long-term changes in HRQL relative to a traditional exercise intervention alone. Additionally, greater minutes of objectively-determined PA were related to higher HRQL following the cessation of the structured exercise interventions. These results underscore the importance of promoting long-term maintenance of PA in sustaining the HRQL benefits that accompany PA interventions targeting older KOA patients.

Supported by NIH/NIAMS R21 AR054595

588 MAY 30 10:45 AM - 11:00 AM

Does the Relationship Between Affect and Exercise Intensity Apply to High-Intensity Interval Exercise?

Mary E. Jung, Wendi L. Wright, Amy E. Wright, Philip N. Ainslie, Jonathan P. Little. University of British Columbia, Kelowna, BC, Canada.

(No relationships reported)

Exercise guidelines promote moderate- over vigorous-intensity activities under the assumption that moderate-intensity exercise is better tolerated and will lead to improved adherence. Traditional forms of continuous moderate-intensity exercise are time consuming, which is problematic given that lack of time is the most commonly reported barrier to regular exercise participation. Recent evidence indicates that low-volume high-intensity interval training (HIT) promotes similar health benefits as continuous moderate-intensity exercise in significantly less time. A bout of HIT consists of brief intervals of vigorous exercise interspersed with short rest periods. The rest periods, and the decreased time commitment, may make HIT more palatable than continuous vigorous-, or even continuous moderate-intensity exercise. The affective response and tolerability to HIT have yet to be empirically tested.

PURPOSE: To compare the affective response during HIT to continuous moderate- and vigorous-intensity exercise.

METHODS: In counter-balanced randomized order, 38 sedentary adults completed continuous moderate-intensity exercise (CMI: 40 min @ ∼65% maximal heart rate [HRmax]); continuous vigorous-intensity exercise (CVI: 20 min @ ∼ 90% HRmax); and acute HIT (10 × 1-min intervals @ ∼ 90% HRmax interspersed with 1-minute recovery). Affect was assessed using the Feeling Scale (FS) at 6 time points during each exercise bout, as well as pre-post. Perceived enjoyment for each type of exercise was assessed following each bout.

RESULTS: There was a significant interaction between time and condition (p = .02), such that HIT elicited significantly greater positive affective responses throughout exercise than CVI (p < .01). Positive affect during CMI was greater than both HIT and CVI (p < .01). Perceived enjoyment was also significantly different between conditions (p = .02), with CMI and HIT rated as more enjoyable than CVI and no differences between CMI and HIT.

CONCLUSIONS: CMI elicited the most positive affect. Despite an equal relative exercise intensity, affect was more positive in HIT compared to CVI. These findings suggest that the rest periods built into HIT may modify the exercise intensity-affect relationship, contributing to greater perceived enjoyment for vigorous exercise performed as intervals.

589 MAY 30 11:00 AM - 11:15 AM

Reinforcing Value Of A Moderately Physiologically-challenging Active Video Game Versus A Minimally-challenging Active Video Game

Megan L. Williamson1, Gabriel Sanders1, Andrew Carnes1, Antonio S. Salvo2, Ellen L. Glickman, FACSM1, Jacob E. Barkley1. 1Kent State University, Kent, OH. 2University of Nevada, Las Vegas, Las Vegas, NV.

(No relationships reported)

BACKGROUND: Physically-interactive active video games (AVG) require greater energy expenditure to play relative to traditional sedentary video games. However, not all AVGs are challenging enough to be considered at least moderate-intensity physical activity. Therefore, simply playing AVGs does not guarantee that one is participating in moderate-intensity physical activity. Because only certain AVGs provide an avenue to increase physical activity in youth it is important to understand how motivated children are to play these moderately physiologically-challenging AVGs versus other, minimally-challenging AVGs.

PURPOSE: The purpose of the current investigation was to assess the oxygen consumption (VO2 ml·kg-1·min-1) and relative reinforcing (motivating) value (RRV) of a moderately physiologically-challenging AVG (Nintendo Wii-Sports Boxing (Wii Boxing)) versus a minimally-challenging AVG (Nintendo Wii Lego Star Wars (Wii Lego)).

METHODS: VO2 was recorded in children, (N = 9, 7.8 ± 1.3 years old) during three, 10-minute conditions; resting in a recumbent position, playing Wii Boxing and Wii Lego. Resting was completed first and the order of AVG play was randomized. After completing the three conditions, children performed an operant button pressing computer task using a progressive fixed ratio schedule to assess the RRV of Wii Boxing versus Wii Lego. Children worked to earn access to a total of 11 minutes for Wii Boxing or Wii Lego or a combination of the two games. The output maximum (Omax) or maximum number of responses performed to earn access to each game was the measure of RRV.

RESULTS: There was a significant (p ≤ 0.03) step-wise increase in VO2 from resting (4.3 ± 1.2 ml·kg-1·min-1) to Wii Lego (5.3 ± 1.5 ml·kg-1·min-1) and from Wii Lego to Wii Boxing (11.7 ± 4.2 ml·kg-1·min-1). There was no significant difference (p = 0.92) in Omax between Wii Lego (114.5 ± 171.1 presses) and Wii Boxing (126.1 ± 219.3 presses).

CONCLUSION: As expected, oxygen consumption in the moderately physiologically-challenging AVG was significantly greater than the minimally physiologically-challenging AVG. Despite this greater physiologic challenge, children’s motivation to play Wii Boxing was almost identical to that of the minimally physiologically-challenging Wii Lego.

590 MAY 30 11:15 AM - 11:30 AM

Desired Physical Competence and Perceived Fitness among Community Health Center and Fitness Center Older Adults

NiCole R. Keith, FACSM1, Stephanie Greer1, Lakenvia Ledford2. 1Indiana University Purdue University, Indianapolis, Indianapolis, IN. 2Indiana University, Bloomington, IN.

(No relationships reported)

Physical fitness is a positive health indicator that delays functional decline and disability while enhancing performance of activities of daily living and independence. Perceived physical fitness and desire for physical competence may be related and could influence overall capabilities.

PURPOSE: We examined the relationship between the desire for physical competence and perceived physical fitness among people who are black and white race aged ≥ 40 yr.

METHODS: To assess this relationship in a group with a wide range of scores, one-half of the participants were recruited from a medically affiliated fitness center (FC) and one-half from a safety net community health center (CHC). The Older Adults Desire for Physical Competence (DPC) survey (Rejeski et al. 2006) and Perceived Physical Fitness Scale Questions (PFSQ - Abadie et al. 1988) were used during the assessment. Participants were read the DPC survey and asked to respond to whether they had “no desire whatsoever,” a “low desire,” “moderate desire,” “strong desire,” or “very strong desire,” to perform certain physical activities. Next participants were read the PFSQ and asked whether they “strongly disagreed,” “disagreed,” were “undecided,” “agreed,” or “strongly agreed,” with statements related to their physical fitness. Analysis: IBM SPSS Statistics 19 was used to perform Spearman correlations that determined the association between variables.

RESULTS: There were 101 males, 100 females, 59 black and 142 white participants aged 54.7±6.1 yr (range = 40-81yr). The mean DPC survey score was 61.8 ± 16.22 (range = 18-80; possible range 0-80). The Mean PFSQ score was 36.78 ± 9.53 (range = 13-60; possible range 0-60). Results demonstrated that desire for physical competence was correlated with perceived physical fitness (r = 0.443, p<0.001).

CONCLUSION: Previous research shows that physical activity and exercise training are associated with a desire for physical competence in older adults. This desire may also influence perceived and actual physical fitness. We found no other studies identifying a relationship between the desire for physical competence and physical fitness. Future research will examine these associations with measured physical fitness. Such relationships may inform intervention strategies to improve physical fitness in older adults.

B-19 Free Communication/Slide - Resistance Exercise

MAY 30, 2012 1:00 PM - 3:00 PM

ROOM: 2005

591 Chair: Gary Liguori, FACSM. North Dakota State University, Fargo, ND.

(No relationships reported)

592 MAY 30 1:00 PM - 1:15 PM

Changes in Maximal Strength With Two Different Models of Daily Undulating Periodization in Trained Powerlifters

Michael C. Zourdos1, Andy V. Khamoui1, Edward Jo1, Bong-Sup Park1, Sang-Rok Lee1, Lynn B. Panton, FACSM1, Robert J. Contreras1, Michael J. Ormsbee1, Jacob M. Wilson2, Jeong-Su Kim1. 1The Florida State University, Tallahassee, FL. 2The University of Tampa, Tampa, FL.

(No relationships reported)

Daily Undulating Periodization (DUP), which consists of hypertrophy, strength, and power training all in a given week, has been demonstrated to produce greater strength gains than linear periodization in trained males. However, the traditional DUP (TDUP) configuration calls for strength training to be performed just 48 hours following hypertrophy training each week. Thus, in TDUP, performance during strength training may be compromised due to residual fatigue from hypertrophy training, which might impede overall strength adaptations.

PURPOSE: To determine if a model of DUP, which provides greater separation between hypertrophy and strength training each week by separating hypertrophy and strength training with a power training day (HPS), yields greater one-repetition maximum (1-RM) gains than TDUP.

METHODS: Fifteen well-trained powerlifters (age: 21.13±1.19 body weight: 83.8±11.4kg) were assigned to one of two DUP training groups for six weeks: 1) TDUP (HSP, n=6): hypertrophy (Mon), strength (Wed), and power (Fri) training or 2) HPS (n=9): hypertrophy (Mon), power (Wed), and strength (Fri) training each week. Subjects performed the squat and bench press during each session with the addition of the deadlift exercise during the strength session only. One-RM strength was assessed on the three performed exercises before and after the 6-week training period in accordance with USA Powerlifting (USAPL) standards. Data were analyzed using a 2×2 repeated measures ANOVA, and significance was set at p<0.05.

RESULTS: Following the 6-week training period main time effects were found for squat (+9.23%), bench press (+5.97%), deadlift 1-RMs (+7.05%) as well as for the average total (sum of the three lifts, +7.46%). A significant group × time interaction was observed only in the bench press 1-RM. Our post-hoc analysis revealed that the main time effect in bench press 1-RM was driven primarily by HPS, which significantly increased 1-RM (8.13%) while HSP did not.

CONCLUSION: Both DUP models effectively increased strength in trained powerlifters. However, a modified model (HPS) can further facilitate strength gains in certain exercises than TDUP. Further analysis will be necessary to understand the underlying mechanisms behind these findings.

593 MAY 30 1:15 PM - 1:30 PM

Post Activation Potentiation: A Meta Analysis Examining The Effects Of Volume, Rest Period Length, And Conditioning Mode On Power

Jacob M. Wilson1, Pedro J. Marin2, Nevine Duncan1, Jeremy P. Loenneke3, Edward Jo4, Michael C. Zourdos4, Lee Brown, FACSM5. 1The University of Tampa, Tampa, FL. 2European University Miguel de Cervantes, Valladolid, Spain. 3The University of Oklahoma, Norman, OK. 4The Florida State University, Tallahassee, FL. 5California State University, Fullerton, Fullerton, CA. (Sponsor: Lee Brown, FACSM)

(No relationships reported)

Post activation potentiation (PAP) is a phenomenon whereby muscular performance is enhanced acutely by a previous activity, that is executed at a relatively higher intensity (e.g. a one repetition maximum (1-RM) back squat performed prior to a vertical jump).

PURPOSE: The primary objective of this investigation was to identify the optimal prescription (e.g. volume, rest period length, and conditioning mode) needed to maximize PAP as it concerns power.

METHODS: A meta-analysis using 31 primary studies was performed with a total of 141 effect sizes. In order to be included in the analysis the study must have had a primary focus on the effects of a conditioning mode on a specific outcome variable which directly measured power (force × velocity ) or used an outcome variable associated with power such as the vertical jump, sprint or Wingate test.

RESULTS: The mean overall ES for muscle power was 0.38 [95% CI: 0.21, 0.55]. Moderating variables Significant differences were found between moderate intensity 1.06 [95% CI: 0.54, 1.57; n: 15] and heavy intensity 0.31 [95% CI: 0.13, 0.49; n: 121] (P < 0.05). Significant differences were found between single sets 0.24 [95% CI: 0.37, 0.44; n: 95) and multiple sets 0.66 [95% CI: 0.36, 0.95; n: 46] (P < 0.05). Significant differences were found between rest periods of 3-7 minutes 0.54 [95% CI: 0.31, 0.77; n: 75] and >10 minutes 0.02 [95% CI: -0.33, 0.38; n:31] (P < 0.05), as well as between rest periods of 7-10 minutes 0.70 [95% CI: 0.10, 1.30; n: 11] and >10 minutes 0.02 [95% CI: -0.33, 0.38; n:31] (P < 0.05).

CONCLUSIONS: Our results suggest that post activation potentiation optimized with multiple sets, performed at moderate intensity (60-84 % 1-RM), with a rest period length corresponding to 3-7 minutes.

594 MAY 30 1:30 PM - 1:45 PM

Effects of Short-Term Isokinetic Reciprocal Action Training on Neuromuscular Performance

Martim Bottaro1, Rafael R. Cunha1, Rodrigo L. Carregaro2, André Martorelli1, Diego Jesus1, Rogerio A. Guedes1, Lee E. Brown, FACSM3. 1University of Brasilia, Brasilia, Brazil. 2Federal University of Mato Grosso do Sul, Campo Grande, Brazil. 3California State University at Fullerton, Fullerton, CA.

(No relationships reported)

Previous studies have shown that preloading an antagonist muscle, such as performing reciprocal muscle actions (RA), may increase acute agonist neuromuscular performance. In addition, studies have suggested that very short-term training programs (2-3 training sessions) may also be useful for increasing muscular performance.

PURPOSE: To examine the effects of three days of RA isokinetic training on knee extension (KE) neuromuscular performance.

METHODS: Twenty nine young men (21.1 ± 2.3 yrs) were randomly assigned to three training groups: 1) RA (n=11; 4 sets of 10 reciprocal isokinetic concentric knee flexion [KF] and KE at 60°.s-1); 2) non-preload traditional training (TR; n=10; 4 sets of 10 unilateral isokinetic KE at 60°.s-1); and control (CO; n=8). All subjects were tested for maximal strength isokinetic KE at 60°.s-1and 180°.s-1 before and after 3 days of training. Electromyography from the agonist vastus medialis (VM) and antagonist biceps femoris (BF) muscles were recorded.

RESULTS: Peak torque (PT) results are presented in Table 1. There were no significant changes in VM activation among groups and between pretest and posttest. However, BF co-activation showed a significant decline after the RA (-14.0 at 60°.s-1and -37.0% at 180°.s-1) and TR (-24.0 at 60°.s-1and -33.0 % at 180°.s-1). There were no significant changes in muscle co-activation in the CON group (-3.0 at 60°.s-1and 3.0% at 180°.s-1).

CONCLUSION: These results indicate that 3 sessions of RA at 60°.s-1 resulted in a greater increase in PT at slow and fast velocities when compared to non-preload TR training. Less co-activation from the RA may suggest that the training-induced strength gains in KE were caused by a decrease in activation of the BF muscle.

Table 1
Table 1
Image Tools

595 MAY 30 1:45 PM - 2:00 PM

Greater Energy Expenditure in Unilateral vs. Bilateral Weight Training

Evan H. Nakachi, J. Brent Feland, Dennis Eggett. Brigham Young University, Provo, UT. (Sponsor: J. Ty Hopkins, FACSM)

(No relationships reported)

Several studies have been conducted on the energy expenditure of traditional bilateral weight training. However, there have not been studies that examined the energy expenditure of unilateral weight training. Generally, unilateral weight training requires greater stabilization than bilateral weight training and should require greater energy expenditure with equal workloads.

PURPOSE: To compare the energy expenditure between unilateral and bilateral weight training.

METHODS: Seven male volunteers (age: 22.5 ± 6.5 y, wt: 80 ± 21 kg, ht: 181 ± 9 cm) were randomly assigned to an initial unilateral or bilateral workout followed by an opposing workout at least two days later. The unilateral workout was performed one limb at a time in an alternating manner. The bilateral workout was performed with both limbs working in unison. The workouts consisted of 2 groups of 3 exercises done in a circuit for 4 sets of 10 repetitions at 60% 1RM. A portable metabolic system recorded the metabolic activity of each lifter’s workout plus 10 minutes of EPOC.

RESULTS: The total energy expenditure for the workout plus 10 minutes of EPOC was significantly greater for the unilateral vs. the bilateral workout (962 kJ vs. 1303 kJ p=0.003). The energy expenditure (EE), oxygen consumption (VO2) and heart rate (HR) for the workout plus 10 minutes of EPOC were significantly greater in the unilateral workout compared to the bilateral workout (EE: 37.79 kJ/min vs. 34.16 kJ/min p=0.019; VO2: 21.7ml/kg/min vs. 19.3 ml/kg/min p=0.039; HR: 152.4 bpm vs. 147.9 bpm p=0.033). Time to complete the workout excluding the 10 minutes of EPOC took significantly more time in the unilateral workout than the bilateral workout (24.5 min vs. 18.2 min p=0.003).

CONCLUSIONS: The unilateral workout produced greater total EE than the bilateral workout, but took more time to complete. Longer workout time could explain the difference in total EE, but it could not explain the unexpected higher average EE and HR of the unilateral workout. This occurred despite requiring 35% more time to complete the unilateral workout. Lower average EE and HR is expected when taking more time to do the same amount of work. Instead the unilateral workout utilized an average of 11% more kJ per minute and produced higher HR than the bilateral workout.

596 MAY 30 2:00 PM - 2:15 PM

Training for Maximal vs. Explosive Strength Elicits Distinct Neuromuscular Adaptations

Neale A. Tillin1, Matthew T.G Pain2, Jonathan P. Folland2. 1University of Roehampton, London, United Kingdom. 2Loughborough University, Loughborough, United Kingdom.

(No relationships reported)

Maximal and explosive force production (peak and slope of the force-time curve, respectively) are distinct components of neuromuscular strength that are both influenced by the level of agonist activation. However, training for maximal strength may elicit distinct neural adaptations to those elicited when training for explosive strength, but this hypothesis has not previously been tested.

PURPOSE: To compare the neuromuscular adaptations to training for maximal vs. explosive strength.

METHODS: 19 untrained males completed either maximal strength (MS; n = 9) or explosive strength (ES; n = 10) training. Both groups performed 4 sets of 10 isometric knee extensions, 4 times a week for 4 weeks. In each contraction the MS group were instructed to contract to 75% of their maximal voluntary force (MVF) and hold for 3-s, whilst the ES group were instructed to push as fast and hard as possible for ∼1-s. Pre and post training measurements included recording MVF (greatest force of 3 maximal voluntary contractions) and force at 50, 100 and 150 ms from force onset during the same explosive contractions as those performed in training by the ES group. To assess agonist activation, EMG of the three superficial quadriceps was recorded at MVF and between 0-50, 50-100, and 100-150 ms during the explosive contractions. EMG variables were normalised to a maximal M-wave elicited via supramaximal stimulation of the femoral nerve, and averaged across the three muscles.

RESULTS: MVF increased in both groups (MS, +21%; ES, +11%; P≤0.001), but this increase was greater in the MS group (ANOVA; group × time, P<0.05). This appears to be due to an increase in agonist normalised EMG at MVF in the MS (+28%; P<0.05), but not the ES group. In contrast, explosive force at all time points increased in the ES group by 13-54% (P<0.01), but was unchanged in the MS group. This appears to be due to greater normalised agonist EMG between 0-50 ms in the ES group (+42%; P<0.05), whist normalised agonist EMG in the MS group during the explosive contractions was unchanged.

CONCLUSION: This is the first study to document distinct neuromuscular adaptations to training for maximal vs. explosive strength. Specifically, MVF and agonist activation at MVF increased in the MS group, whilst explosive force and initial agonist activation during explosive contractions increased in the ES group.

597 MAY 30 2:15 PM - 2:30 PM

Increase in Muscle Size Following 5-wk Resistance Training is Exaggerated by Concurrent Aerobic Exercise

Tommy R. Lundberg1, Rodrigo Fernandez-Gonzalo2, Sofie Åkerström1, Per A. Tesch2. 1Mid Sweden University, Östersund, Sweden. 2Karolinska Institute, Stockholm, Sweden.

(No relationships reported)

While chronic aerobic and resistance training aim at contrasting physiological outcomes, it has been questioned if skeletal muscle adaptations, typically induced by resistance exercise and resulting performance features, are compromised if combined with aerobic exercise.

PURPOSE: The object of the study was to explore the effects of a 5-wk resistance training program with or without concurrent aerobic exercise, on muscle size, strength and power.

METHODS: Ten moderately trained men (25±4 yrs, 184±6 cm and 83±13 kg) performed 5 wks of unilateral knee extensor aerobic and resistance exercise (AE+RE). The opposing limb was subjected to resistance exercise (RE) only. Subjects completed 12 RE and 15 AE sessions, such that RE was scheduled 6 hrs after AE on the same day. AE sessions consisted of ∼45 min unilateral exercise at ∼70% of peak power on a one-legged cycle ergometer. RE comprised 4 × 7 maximal concentric-eccentric knee extensions using flywheel ergometry. Maximal isokinetic and isometric strength and flywheel peak power were measured before and after training. Endurance performance was determined by a one-legged incremental workload test. M. quadricep volume was assessed by magnetic resonance imaging (MRI).

RESULTS: While both legs showed improved endurance performance (time to exhaustion) after training (p<0.05), the increase was more prominent after AE+RE than RE (27 vs. 19%). The increase (p<0.05) in peak power was similar for AE+RE (400 to 514W) and RE (406 to 502W). Maximal isometric strength increased (p<0.05) by 9 (AE+RE) and 11% (RE), respectively. Neither strength nor power differed between legs before or after training (p>0.05). All four individual quadricep muscles showed increased (p<0.05) volume. The increase in total quadricep volume was greater (p<0.05) for AE+RE (14%) than RE (8%). Signal intensity of MRI scans increased (p<0.05) by 12% after AE+RE, with no change in RE (p>0.05).

CONCLUSIONS: The results suggest that performing exhaustive aerobic exercise 6 hrs prior to resistance exercise over 5 wks, does not compromise gains in strength or power resulting from resistance exercise only. If anything, it appears the combined approach promotes a more robust increase in muscle size, not necessarily fully accounted for by an increase in contractile material.

598 MAY 30 2:30 PM - 2:45 PM

Changes in Plasma Free Testosterone and Cortisol Concentrations During Plyometric Depth Jumps

Gregory A. Brown, FACSM1, Bryce M. Abbey1, Michael W. Ray2, Brandon S. Shaw3, Ina Shaw4. 1University of Nebraska Kearney, Kearney, NE. 2BNSF Railway Company, Ft. Worth, TX. 3Tshwane University of Technology, Johannesburg, South Africa. 4Monash South Africa, Johannesburg, South Africa.

(No relationships reported)

Although plyometrics are widely used in athletic conditioning and have numerous benefits, the acute physiological responses to plyometrics have not been well described.

PURPOSE: The purpose of this study was to investigate the changes in plasma free testosterone and cortisol responses to a single session of plyometric depth jumps.

METHODS. Twenty recreationally-trained college aged subjects (10 men, 22.6 ± 1.3 y, 175.6 ± 8.0 cm, 78.9 ± 12.4 kg, 8.0 ± 2.9 % body fat; 10 women 21.4 ± 1.3 y, 167.4 ± 7.7 cm, 65.6 ± 7.3 kg, 23.2 ± 6.7 % body fat) participated in a single session of eight sets of 10 box depth jumps from a height of 0.8 meters with three minutes of passive recovery between each set. All testing began at 8:00 a.m. Blood samples were collected without stasis at rest, immediately after the fourth set of depth jumps, and immediately after the final set of depth jumps. Plasma samples were analyzed for free testosterone and cortisol concentrations using ELISA. Data were analyzed using a 2 way (Gender X Time) repeated measures ANOVA.

RESULTS: There were significant (P<0.05) differences in the resting free testosterone concentrations between women (12.1 ± 7.2 nmol/l) and men (95.3 ± 9.3 nmol/l). Plyometric depth jumps elicited an ∼11% increase (P<0.05) in plasma free testosterone concentrations in women and an ∼22% increase (P<0.05) in plasma free testosterone concentrations in men. The increase in plasma free testosterone concentrations was greater in men than in women (P<0.05). Resting plasma cortisol concentrations were not different between men (295.0 ± 5.0 nmol/l) and women (295.3 ± 6.2 nmol/l). Plyometric depth jumps elicited an ∼64% increase (P<0.05) in plasma cortisol concentrations in men and women, with no differences due to gender.

CONCLUSIONS: These data suggest that plyometric depth jumping from a height of 0.8 meters elicits increases in serum testosterone and cortisol concentrations similar to previous observations with 8 sets of 10-RM squats. However, women demonstrated less of an increase in free testosterone concentrations than did men.

599 MAY 30 2:45 PM - 3:00 PM

Effects Of Eight Post Activation Potentiation Protocols On Jump And Sprint Performance In College Athletes

Fernando Naclerio1, Avery Faigenbaum2, Eneko Larumbe3, Paul E. Friedman2, Nicholas Ratamess2. 1Greenwich university, chatham Maritime, Kent, United Kingdom. 2The College of New Jersey, Ewing, NJ. 3European University of Madrid, Urbanizacion el Bosque s/n, Spain.

(No relationships reported)

PURPOSE: The aim of this study was to examine the effects of 8 different parallel squat (PS) postactivation potentiation (PAP) protocols with and without neuromuscular vibration on jumping and sprint performance in college athletes

METHODS: 15 male athletes (20.3± 1.3 yr, 179.50±5.3 cm, 81.0±10.8 kg) were exposed to 3 basic conditions: 1) PS with 80% 1 RM on stable surface (S); 2) PS with 80% 1 RM onto a whole body vibration platform (1.7 to 2.3 mm amplitude and 40Hz) (V) and 3) control sham condition with no PS or V. Each of the three conditions was performed for 1 set of 3 reps or 3 sets of 3 reps followed by a passive period of 1 min or 4 min rest before performing 3 reps of countermovement jump (CMJ), 1 drop jump (DJ) and a 30 m sprint. In order to determine 80% of the 1RM as the performance reference, before (T1) and after (T2) the intervention protocols, the subjects performed a 1 RM squat, CMJ, a progressive drop jump test on the force plate, as well as a maximum 30 m sprint on a Woodway Force 3.0 treadmill. The CMJ, DJ height, power as well as the velocity and power of the 30m sprint were measured after each protocol and compared with the performance measured at T1 and T2 as well as between the results obtained in each of the particular conditions.

RESULTS: We found that there were no significant (p>0.05) differences between the height, power or velocity assessed in CMJ, DJ or the 30m sprint respective to the results obtained following T1 or T2

CONCLUSIONS: Neither, S or V protocols with shorter (1min) or longer (4min) rest periods elicited any PAP effect on height and power achieved on CMJ and DJ as well as on measures of speed and power in the 30 m sprint in male college athletes. The large variability in performance observed among subjects as well as their level of fitness performance may have masked the possible PAP effects produced by the stable or V protocols. In order to achieve the possible benefits of a PAP strategy with or without V, practitioners should evaluate different combinations of intensity, volume, rest periods and exercise stimuli in order to elicit the desired effects in performance in their athletes.

B-66 Free Communication/Slide - Cardiac Rehabilitation (Clinical Exercise Physiology Association)

MAY 30, 2012 3:15 PM - 5:15 PM

ROOM: 3014

600 Chair: Dalynn T. Badenhop. University of Toledo Medical Center, Toledo, OH.

(No relationships reported)

601 MAY 30 3:15 PM - 3:30 PM

Skeletal Muscle Wasting And Muscle Function In Heart Failure Patients Of Different Ages - Effects Of Endurance Training

Marcus Sandri, Volker Adams, Norman Mangner, Gerhard Schuler, Stephan Gielen. University of Leipzig, Leipzig, Germany. (Sponsor: Jonathan N. Myers, FACSM)

(No relationships reported)

INTRODUCTION: Despite its prognostic implications the mechanisms of skeletal muscle wasting in chronic heart failure (CHF) are still not completely understood. We have previously documented activation of the catabolic ubiquitin-proteasome system (UPS) with an increased expression of Murf-1 in skeletal muscle biopsies of CHF patients. However, it is unclear, if the second skeletal muscle specific E3-ligase MafBX is also involved in the wasting process and how Murf-1 and MafBX respond to exercise training in CHF patients of different age groups.

METHODS: 60 CHF patients and 60 healthy subjects (HS) were randomized to 4 weeks of bicycle ergometer training at 70% of the heart rate reserve 4 × 20 min/day or to a control group (C). Before and after the intervention a spiroergometry, echocardiography, a force endurance measurement and a muscle biopsy of the vastus lateralis muscle were performed. Expression of the E3 ligases Murf-1 and MafBX was quantified by real-time PCR standardized for 18S-rRNA and Western blot.

RESULTS: (1) Clinical Training Effects: In younger CHF patients (n= 15, age 45±3 years, BMI 26.8±2.7, LV-EF 26.8±2.6%) training improved force endurance from 31±3 to 45±4 seconds (p=0.004 vs. control). In elderly CHF patients (n=15, age 68±4 years, BMI 25.3±2.9, LV-EF 27.4±3.0%) training increased force endurance from 35±4 to 47±7 seconds (p=0.01 versus control). (2) Molecular Training Effects: At baseline Murf-1 mRNA expression in CHF patients was elevated versus HS at 624±59 versus 401±25 rel. units (p=0.007) and protein expression at 0.82±0.09 versus 0.57±0.04 rel. units (p=0.01). MafBX mRNA and protein expression did not differ in CHF patients and healthy subjects and did not change with age. Training was associated with a reduction of Murf-1 expression by 34.3% (p=0.02) in younger CHF patients and a reduction of 24.3% (p<0.05) in elderly. MafBX did not show any significant response to training.

CONCLUSIONS: Exercise training equally improves skeletal muscle function in younger and older patients with CHF. These clinical data underline the importance of exercise-based rehabilitation programs to prevent CHF related muscle wasting. On a molecular level, the activation of Murf-1 is reduced by the training intervention while MafBX levels remain unaffected by both CHF and the training intervention.

602 MAY 30 3:30 PM - 3:45 PM

N Terminal-pro-brain (b-type) Natriuretic Peptide But Not Left Ventricular Ejection Fraction Is Correlated With Exercise Capacity In Postinfarction Patients

Fernando Ribeiro1, Nortón Luis Oliveira2, Alberto Jorge Alves3, Madalena Teixeira4, Fátima Miranda4, Cristina Azevedo4, José Alberto Duarte3, José Oliveira3. 1CESPU, Polytechnic Health Institute of the North, Gandra PRD, Portugal. 2University of Porto, Faculty of Sport, 4200.450 Porto, Portugal. 3University of Porto, Faculty of Sport, Porto, Portugal. 4Centro Hospitalar de Gaia/Espinho, Vila Nova de Gaia, Portugal.

(No relationships reported)

Attempts to correlate exercise capacity with traditional systolic function markers such as left ventricular ejection fraction (LVEF) could only demonstrate weak correlations. Circulating levels of brain natriuretic peptide and N-terminal-pro-brain (B-type) natriuretic peptide (NT-pro-BNP) have emerged as a sensitive and accurate method for assessment of left ventricular function.

PURPOSE: The aim of this study was to determine whether NT-pro-BNP levels are associated with LVEF and exercise capacity as measured by cardiopulmonary exercise testing in patients with coronary heart disease.

METHODS: We prospectively studied 79 consecutive patients (age: 57.5 ± 10.5 years; height: 1.68 ± 0.08 m; weight: 78.2 ± 12.6 kg) with recent history of acute myocardial infarction (AMI) referred for cardiopulmonary exercise testing. All patients underwent resting blood sample collection for NT-pro-BNP assessment, resting echocardiography and cardiopulmonary graded exercise test six weeks after AMI (65% percutaneous coronary intervention). First, associations among exercise capacity and the variables age, sex, NT-pro-BNP levels, LVEF were tested by Pearson correlation. Then, partial correlation between exercise capacity and NT-pro-BNP levels was ascertained controlling for age and sex.

RESULTS: Exercise capacity (VO2 peak: 29.3 ± 7.1 ml/kg/min) was significantly associated with age (r = -0.538, p<0.001) and NT-pro-BNP levels (548.8 ± 521.7 pg/ml; r = -0.316, p<0.05). After adjustment for age and sex, higher values of VO2 peak remained associated with low levels of NT-pro-BNP (r = -0.249, p<0.05).

CONCLUSIONS: Exercise capacity is not related to conventional measures of systolic function, such as LVEF, being correlated with NT-pro-BNP even after adjustment for age and sex. Our results suggest that biochemical detection of left ventricular function is best associated with exercise capacity than echocardiography-based measures. Our findings may be applied to patients unable to perform cardiopulmonary exercise testing; in such patients the assessment of NT Pro BNP can provide useful clinical information.

Acknowledgments: To The Portuguese Fundação para a Ciência e a Tecnologia (FCT) for the following grants: SFRH/BPD/69965/2010 and PTDC/DES/113753/2009.

603 MAY 30 3:45 PM - 4:00 PM

Submaximal Exercise Testing During Outpatient Cardiac Rehabilitation Identifies Reduction In Abnormal Heart Rate Recovery

Phil A. Lees1, Jane Hedgpeth-Kessler2, Susan Rodearmel1. 1California State University, East Bay, Hayward, CA. 2John Muir Health, Walnut Creek, CA. (Sponsor: Jonathan Myers, FACSM)

(No relationships reported)

Abnormal heart rate recovery (HRR) values at 1-min (HRR1 ≤ 12 bpm) and 2-min (HRR2 ≤ 22 bpm) immediately following exercise testing have been shown to be independent predictors of overall mortality risk. Recent studies suggest that exercise training can improve post-exercise HRR, and routine assessment of HRR during exercise testing has been proposed. However, most of this earlier work was retrospective in design and/or used symptom-limited maximal exercise testing.

PURPOSE: To evaluate the use of a submaximal exercise test with active cool down for identifying HRR abnormalities and for measuring changes in HRR resulting from outpatient cardiac rehabilitation (CR).

METHODS: Twenty patients (aged 62±10y) referred to Phase II CR following myocardial infarction (MI), coronary artery bypass surgery (CABG), percutaneous coronary intervention (PCI) or stable angina, were consecutively enrolled in a study program with supervised exercise training sessions 3 days/week for up to 12 weeks. Submaximal fitness evaluation treadmill tests (fit-evals) were performed twice during the CR program - once at the beginning, and once at the end - and peak workloads were limited by rating of perceived exertion (RPE) = 13. Fit-evals were adapted to include a six-minute active recovery phase immediately following the peak workload with HR recorded at the end of each recovery minute.

RESULTS: A total of fourteen patients (70%) exhibited abnormal HRR during initial fit-eval, decreasing to only six patients (30%) with abnormal HRR during final fit-eval. As a result of completing CR, HRR1 increased by 72% (10.1±7.0 to 17.4±7.6 bpm, p < 0.001) and HRR2 increased by 48% (20.2±9.7 to 30.0±10.0 bpm, p < 0.001). In addition, HR reserve increased by 31% (45.9±10.2 to 60.1±13.8 bpm, p < 0.001) and HR peak increased by 10.7% (116±14.3 to 128±13.3 bpm, p < 0.001), but there was no significant change in resting HR. All but one of the patients were taking β-blockers.

CONCLUSIONS: A submaximal exercise test is suitable for use in outpatient CR programs to track HRR improvements in patients with recent MI, CABG, PCI or angina, and to identify high-risk patients with abnormal HRR. Completion of an outpatient CR program provides overall improvements in HRR and HR peak, and offers the greatest risk-reduction benefit to those patients entering CR with abnormal HRR.

604 MAY 30 4:00 PM - 4:15 PM

Effects of Supplemental Home-Based Walking on Cardiac Rehabilitation Clinical Outcomes

Addison Pica1, Peggy A. Plato2, Trish Sevene1, Craig J. Cisar, FACSM2. 1CSU Monterey Bay, Seaside, CA. 2San Jose State University, San Jose, CA.

(No relationships reported)

Cardiac rehabilitation (CR) programs focus on improving aerobic endurance and modifying cardiovascular risk factors through lifestyle changes, including physical activity and diet. Moderate physical activity, such as walking, modifies multiple cardiovascular risk factors, and is a convenient and behaviorally feasible form of exercise.

PURPOSE: To evaluate the effects of supplemental, home-based walking on resting systolic blood pressure (SBP), waist circumference, and quality of life (QoL) in CR patients.

METHODS: Sixteen Phase 2 CR patients (13 M, 3 F, 67 ± 3 yrs, 170.5 ± 2.2 cm, 89.8 ± 3.6 kg) wore pedometers for 4 weeks outside of the CR facililty. Resting SBP, waist circumference, and QoL were measured at weeks 1 (pre), 8 (mid), and 12 (post). Pedometers were worn between weeks 8 and 12. Average weekly steps were used to categorize patients into low and high step groups. Steps (M ± SEM) for the low and high groups were 9,505 ± 1727 and 37,585 ± 10,627, respectively, p<0.001. Two-way repeated measures ANOVA was used to evaluate group and time differences.

RESULTS: There was a significant interaction effect for SBP (p = 0.016), with pressure increasing in the low step group over the 12 week program (pre: 112 ± 4 mm Hg, mid: 126 ± 5, post: 130 ± 6) and minimal change in the high step group (pre: 120 ± 8 mm Hg, mid: 116 ± 7, post: 118 ± 7). Although waist circumference decreased 2.2 ± 1.4 cm in the high step group and increased 1.7 ± 1.5 cm in the low step group over the 12 week program, there were no significant group or time effects. The change in waist circumference over 12 weeks (post-pre) was significantly correlated with average weekly steps (R = -0.585, p=0.017), indicating that as steps increased, waist circumference decreased. Scores on the Dartmouth QoL Index significantly improved over the 12 week program, with lower scores indicating a higher QoL (22.9 ± 1.5 pre vs. 17.2 ± 1.0 post, p=0.003). There were no differences in QoL scores between the low and high step groups.

CONCLUSION: Supplemental walking affected SBP, with better outcomes in patients who accumulated more walking steps outside of the CR program. Increased walking correlated with reductions in waist circumference. The amount of supplemental walking did not affect QoL scores, but QoL improved during the 12 week CR program.

605 MAY 30 4:15 PM - 4:30 PM

Investigating The Use Of Aerobic Exercise Incorporating Balance Training With A Cardiac Rehabilitation Population

Mairi C. McKinley1, Scott M. Graham2, Christopher Connaboy3, Ewan MacArthur2, Morag Thow4. 1University of Abertay Dundee, Dundee, United Kingdom. 2University of the West of Scotland, Paisley, United Kingdom. 3Edinburgh Napier University, Edinburgh, United Kingdom. 4Glasgow Caledonian University, Glasgow, United Kingdom.

(No relationships reported)

INTRODUCTION: Scotland currently exhibits the highest rates of Coronary Heart Disease (CHD) in the UK. Heart health can be greatly improved through appropriate lifestyle change with exercise as a core element. Within the UK, Phase IV Cardiac Rehabilitation (CR) exercise classes are widely utilised to deliver community-based exercise. CR Phase IV populations are predominantly aged with multiple co-morbidities. The American College of Sports Medicine recognises that these individuals should be prescribed programmes that use intrinsic balance, proprioception, reaction and muscular endurance types of exercise in addition to more traditional CV types of exercise (ACSM, 2009).

PURPOSE: To investigate the effectiveness of an alternative format of aerobic exercise using Fitzone™, a piece of apparatus that incorporates balance activities, as compared to a traditional CR exercise class format.

METHODS: Sixteen participants (m=8, f=8, mean body mass: 81.9 ±21.6 kg, age: 69 ±7.9 yrs) were recruited from Phase IV classes and randomly allocated to either Exercise group (Ex) or Zonefit (ZF) group. Subjects participated in two classes per week for a period of four consecutive weeks. During exercise, RPE values (Borg 6-20 scaling) were collected with Heart Rate continuously recorded using Suunto Team System. Berg’s Balance Scale (BBS) (1989) was used prior to, and post, main exercise period. All exercise patterns and movements were transferrable to the Fitzone™ equipment. All exercises were performed in the same order for both groups and all exercise sessions for comparable lengths of time.

RESULTS: All male subjects in the ZF group improved their balance scores (p=0.004), female values decreased, while the majority of CR group either maintained or decreased their balance values. Similar RPE and HR patterns were observed across the groups.

CONCLUSIONS: The use of non-traditional apparatus such as the Fitzone™ may provide comparable cardiovascular benefits to traditional CR exercise formats with additional improvements in balance and proprioception.

606 MAY 30 4:30 PM - 4:45 PM

Energy Expenditure During An Exercise Training Session For Cardiac Patients

Xavier Melo1, Helena Santa-Clara1, Diana A. Santos1, Rodrigo Martins1, José P. Almeida1, Luís B. Sardinha1, Bo Fernhall, FACSM2. 1Faculty of Human Kinetics, Technical University of Lisbon, Lisbon, Portugal. 2University of Illinois at Chicago College of Applied Health Sciences, Chicago, IL.

(No relationships reported)

BACKGROUND: The measurement of energy expenditure during cardiac rehabilitation (CR) exercise sessions and the guidance of CR training by caloric expenditure consistent with available data indicating a dose of physical activity (PA) in the range of 13 to 26 METs.h-1.wk-1 necessary to attain modest weight loss, have received very little attention.

PURPOSE: We aimed to characterize energy expenditure (EE) in one entire combined aerobic and strength exercise session among patients enrolled in a 3 d.wk-1 maintenance CR program.

METHODS: Twelve overweight/obese male patients with coronary artery disease (age: 62.6 ± 8.5 yrs, weight: 79.7 ± 9.9 kg; BMI: 27.7 ± 2.9 kg.m-2) were assessed during one entire training session. Subjects were instructed to exercise at a 60-70% heart rate reserve (HRR) intensity. Resting (REE) and total energy expenditure (TEE) were measured using indirect calorimetry (K4b2, Cosmed, Rome, Italy). Activity energy expenditure (AEE) was calculated with TEE and REE. Training sessions consisted of a combined aerobic [circuit workout (ACW) and game situation (soccer, basketball or volleyball)] and strength training regimen.

RESULTS: Mean duration of the training session was 75.3 ± 1.5 min, of which 59.0 ± 6.0 min were spent above moderate intensity (3 METs). The average TEE corresponded to 457 ± 80 kcal (3.7 ± 0.5 METs.h-1; 13.9 ± 1.7 METs.h-1.wk-1) and AEE was 309 ± 76 kcal. Warm-up, ACW, game, strength, stretching and transitions fulfilled 11.9 ± 2.4 %, 30.8 ± 5.3 %, 23.7 ± 4.3 %. 15.4 ± 2.2 %, and 1.9 ± 1.1 % of the TEE, respectively. Mean intensity of the fundamental part of the session was: ACW, 6.6 ± 0.4 METs, 59 ± 10 % HRR; Game, 5.8 ± 0.4 METs, 60 ± 15 % HRR; Strength, 3.7 ± 0.2 METs, 46 ± 10% HRR. Significant intensity (METs) differences were observed between the strength part and the ACW and game activities.

CONCLUSION: A combined aerobic and strength regimen training following standard exercise prescription practices is an effective tool to promote PA above the moderate intensity in coronary artery disease patients, allowing patients to meet the EE recommendations for modest weight loss. Future studies will need to evaluate if patients will actually lose weight following this program.

607 MAY 30 4:45 PM - 5:00 PM

Characterization Of Physical Inactivity In Patients Enrolling In An Early-outpatient Cardiac Rehabilitation Program.

Leonard A. Kaminsky, FACSM1, Cemal Ozemek1, Katrina Riggin2, Scott J. Strath3. 1Ball State University, Muncie, IN. 2Indiana University Health-Ball Memorial Hospital, Muncie, IN. 3University of Wisconsin - Milwaukee, Muncie, IN.

(No relationships reported)

A study by Matthews, C.E., et. al. (Am J Epidemiol 2008; 167:875-881) analyzed NHANES data from 6,329 participants (aged 6-85 y) and reported a mean sedentary time of 54.9% of the observed measurement period. Inactivity time has been associated with numerous adverse health outcomes. Information about inactivity time in different populations is needed.

PURPOSE: The primary purpose of this study was to determine how much daily time patients entering an early outpatient cardiac rehabilitation (CR) program spent being physically inactive. The secondary purpose was to examine descriptive correlate characteristics of time spent being physically inactive in this population.

METHODS: One-hundred and twenty-two patients (60.5 ± 11.3 y) enrolling in an early outpatient CR program wore an Actigraph GT3X accelerometer (Pensacola, FL) for one-week prior to beginning CR. Subjects data were included if the accelerometer provided at least 4 days with at least 12 hr/day of wear-time. Physical inactivity was determined by time spent with <100 activity counts/min. Descriptive characteristics included: age, gender, education level, employment status, income level, marital status, dog ownership, and 6 minute walk test distance (6MWT). Data analyses were performed with IBM SPSS Statistics software version 19 (Armonk, NY). Descriptive characteristics were computed as mean ± standard deviation and point-biserial correlation coefficients were determined to compare physical inactivity time, as assessed by accelerometry, to identified correlate characteristics.

RESULTS: Data from this study show that on average, patients entering a CR program spent 72.9 ± 9.3% of the waking day engaged in physical inactivity (observation time 890 ± 90 min/day). Significant correlates of inactivity time were age (r=.27, p< 0.01), being employed (r=.27, p< 0.01), dog ownership (r=-.17, p< 0.06), and 6MWT distance (r=-.22, p< 0.05).

CONCLUSION: These results demonstrate that patients at entry to an early outpatient CR program have a relatively high level of inactivity time. CR professionals regularly counsel patients to be physically active, however they also need to encourage their patients to limit their inactivity time.

This work was supported by an American Heart Association Midwest Affiliate Grant-in-Aid.

608 MAY 30 5:00 PM - 5:15 PM

Using the Duke Activity Status Index to Estimate Functional Capacity in Patients Entering Cardiac Rehabilitation

Lindsey Krajewski, Susan Haapaniemi, Amy Fowler, Barry Franklin, FACSM, Judith Boura, Brenda White. Beaumont Health System, Royal Oak, MI.

(No relationships reported)

The Duke Activity Status Index (DASI) is a self-administered questionnaire that is used to estimate functional capacity (FC) using the DASI 1 equation: VO2 = 0.43 × raw score + 9.6. Metabolic equivalents (METs) are then calculated by dividing VO2, expressed as mL/O2/kg/min, by 3.5. Another method of estimating METs from the DASI raw score: DASI raw score/3.5 (DASI 2), was validated in 476 women with cardiac risk factors. However, the validity of this method in other populations requires clarification.

PURPOSE: The present study compared 2 methods of estimating METs from the DASI raw score: DASI 1 and DASI 2 with estimated METs from graded exercise testing (GXT) results in men and women entering a phase II (PII) cardiac rehabilitation (CR) program.

METHODS: Patients (122 men; 27 women) who entered PII CR and completed a GXT post event and a DASI questionnaire prior to PII entry were evaluated. Estimated GXT METs, based on the achieved entry treadmill speed, grade and duration, were correlated with 2 methods of calculating entry DASI METs. Differences between men and women and patients on and off beta blockers (βB) were also calculated.

RESULTS:

For all patients, a strong linear trend between GXT METs and DASI 1 METs was noted (r = 0.47; P <0.0001). There were no significant differences in any of the paired variables. However, the DASI 2 method overestimated FC in all subsets.

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CONCLUSIONS: The DASI 1 method of estimating FC in coronary patients entering PII CR was comparable to values derived from conventional GXT. In contrast, the DASI 2 method routinely overestimated MET capacity. For patients entering PII CR without a preliminary GXT, the DASI 1 equation may be helpful in formulating appropriate workloads for training.

B-67 Free Communication/Slide - Older Adults

MAY 30, 2012 3:15 PM - 4:45 PM

ROOM: 2005

609 Chair: David R. Brown, FACSM. Centers for Disease Control and Prevention, Atlanta, GA.

(No relationships reported)

610 MAY 30 3:15 PM - 3:30 PM

Multi-modal Training Incorporating High Velocity Resistance Training Improves Bone Density and Function in Older Adults

Jenny Gianoudis1, Christine Bailey1, Peter R. Ebeling1, Caryl A. Nowson2, Kerrie Sanders1, Keith Hill3, Robin M. Daly2. 1University of Melbourne, Melbourne, Australia. 2Deakin University, Melbourne, Australia. 3La Trobe University, Melbourne, Australia.

(No relationships reported)

Recent evidence suggests that power training, characterised by high-velocity muscle contractions, may be more effective for improving bone density and muscle function than traditional progressive resistance training (PRT). However, few studies have evaluated its effectiveness in a ‘real world’ community setting.

PURPOSE: To investigate the effects of a multi-modal exercise program coupled with osteoporosis education/awareness, termed ‘Osteo-cise: Strong Bones for Life’, on bone density, body composition and functional power and performance in older adults.

METHODS: 162 men and women (mean 67 years, range 59 to 86) at increased risk for falls/fractures were randomised to: 1) the ‘Osteo-cise’ program (n=81) or 2) a control group (n=81). Exercise consisted of high-velocity PRT, weight-bearing activities (60-180 impacts/session) and balance training 3 days per week for 12 months. DXA was used to assess total body fat mass (FM) and lean mass (LM) and hip and spine BMD at baseline and 12 months. Lower limb and back 1-RM muscle strength and functional power [stair climbing test] and performance [4-square test, functional reach, timed-up-and-go (TUG), sit-to-stand] were assessed at baseline, 6 and 12 months.

RESULTS: A total of 150 participants (93%) completed the study and the groups were matched at baseline. Exercise attendance averaged 59%. After 6 months, there were significant exercise-induced improvements in back and leg muscle strength [net gains 13% and 12%, P<0.01], which were maintained after 12 months. There was no effect of exercise on weight, LM or FM. However, exercise resulted in a significant net gain of 1.0% and 1.1% in femoral neck and lumbar spine BMD relative to controls (both P<0.05). In addition, there were significant improvements in stair climbing power [net gain 4.7% (1.0, 8.4), P<0.05], sit-to-stand [12.7% (6.0, 19.3), P<0.001] and the 4-square balance test [0.4 sec (-0.7, -0.1), P<0.05] after 6 months training. These benefits were maintained after 12 months.

CONCLUSION: The ‘Osteo-cise: Strong Bones for Life’ multi-component community-based exercise program is effective for improving bone density, muscle strength and functional muscle power and performance in older adults at risk of fracture.

Supported by J.O. & J.R. Wicking Trust (ANZ Trustees) and Osteoporosis Australia.

611 MAY 30 3:30 PM - 3:45 PM

Physical Activity Level and Poor Disability Profile Among Adults with Arthritis

Jennifer Hootman, FACSM, David Brown. CDC, Atlanta, GA.

(No relationships reported)

PURPOSE: To assess the relationship between physical activity (PA) and an overall disability profile among adults with arthritis based on the International Classification of Function (ICF).

METHODS: Data were from the 2009 Behavioral Risk Factor Surveillance System, an annual telephone health survey conducted in all 50 states and the District of Columbia. Arthritis (n= 151,120) was defined as a ‘yes’ response to “Have you ever been told by a doctor or other health care professional that you have arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?”. ICF-based outcomes were: 1) severe pain (PAIN); >7 on a 0-10 scale; 2) activity limitation (AL); limitation in usual activities due to arthritis; 3) social participation restriction (SPR); arthritis interfered with social activities such as shopping, going to movies or social gatherings (A lot vs A little/Not at all); 4) POOR disability profile; persons who reported PAIN, AL, and SPR. Respondents were asked frequency and duration of moderate/vigorous intensity non-occupational PA for at least 10 minutes at a time. Total minutes per week were summed (1 vigorous minute = 2 moderate minutes) and categorized as: Inactive (0 min/wk = referent), Insufficient (10-149 min/wk), and Recommended (150+ min/wk). Logistic regression was used to estimate the relationship (adjusted odds ratio = aOR, 95% confidence interval = CI) between PA level and each ICF outcome adjusting for age, sex, race/ethnicity, education, body mass index, and self-rated health status. All analyses used statistical weights to account for the complex sample design.

RESULTS: Among adults with arthritis, higher levels of PA were associated with significantly lower odds of PAIN (34-42%↓), AL (16-36%↓), and SPR (55-63%↓). The prevalence of having a POOR disability profile by PA level was 26.2% (CI 25.2-27.2) inactive, 12.7% (CI 12.0-13.4) insufficient, and 6.7% (CI 6.4-7.1) recommended. PA was also associated with 41-63% lower odds of having a POOR disability profile (Recommended: aOR 0.37; CI 0.34-0.41, Insufficient aOR 0.59; CI 0.54-0.64).

CONCLUSIONS: At least 1 in 10 adults with arthritis have a poor disability profile. Increasing PA in this population may improve one’s disability profile, although this needs to be tested in prospective randomized controlled trials.

612 MAY 30 3:45 PM - 4:00 PM

Effects of Combined Exercise Program On Functional Fitness For Community-Dwelling Elderly Japanese Women

Hiroshi Kohno1, Hidenori Asai2. 1Toyo Univ. Human Life Design, Asaka-Shi, Saitama, Japan. 2Ehime Univ., Matsuyama-Shi, Ehime, Japan.

(No relationships reported)

PURPOSE: To examine the effects of combined exercise program for the functional fitness promotion program composed of the exercise program and facilitating program for the elderly Japanese women.

METHODS: Participants: The subjects were asked to participate in anti-fall class at the health check event for more than 60 year old community-dwelling people. The subjects were 14 females (64.8±3.8 yrs, BMI26.7±3.5) in the intervention group (IG) and 13 females (65.1±4.8 yrs, BMI 25.4±3.0) in the control group (CG).

Intervention: The program was constituted of a home-based exercise program and group learning to improve balance ability and muscle strength. The exercise program was composed of stretching for flexibility, resistance exercise for muscle strength, and standing on a balance-ball to improve dynamic balance ability. The facilitating program was designed to enhance subjects’ self efficacy for the exercise program using stages of change model. The classes were held once a week for 6 months. Information on functional fitness(Sitting & Standing, Zig-Zag Walking, Hand Working time, and Self-Care Working time) were measured using standardized tests before and after the intervention period. The CG received an ordinary exercise advice booklet.

RESULTS: Before the intervention period, functional fitness level in the IG was not significantly different from those in the CG. The program adherence and class participation were 80.9±22.0% and 89.3% at the end of the intervention period, respectively. IG showed significant improvement in functional fitness as Sitting & Standing time (IG: 4.7±0.7 sec. to 4.2±0.9 sec. ,P<0.05, CG: 4.9±0.8sec. to 4.8±1.0 sec. ,NS, deltaP<0.05), Zig-Zag Walking (IG: 6.2±0.8 sec. to 5.8±0.6 sec. ,P<0.01, CG: 6.0±0.5sec. to 5.8±0.7sec.,NS, deltaP<0.05), Self-Care Working time(IG: 6.9±1.2 sec. to 5.9±0.9sec. ,P<0.001, CG: 7.2±2.0sec. to 7.3±1.8 sec. ,NS, deltaP<0.05), 10times sit and standing time from chair(IG: 9.0±1.3 sec. to 8.6±1.8sec. ,P<0.05, CG: 9.8±1.3sec. to 9.6±1.1 sec. ,NS, deltaP<0.05 )compared to CG.

CONCLUSIONS: These results suggested that the combined exercise program was effective for functional fitness for the elderly Japanese women.

613 MAY 30 4:00 PM - 4:15 PM

Get Fit for Active Living Older Adult Exercise and Educational Program: Adherence at 1-Year Follow-Up

Liza Stathokostas, Rob Little, Mark Speechley, Don H. Paterson, FACSM. University of Western Ontario, London, ON, Canada.

(No relationships reported)

Long term adherence rates to exercise programs in older adults are low. “Get Fit for Active Living” (GFAL) is an 8-week evidence-based physical activity education program developed for older adults by the Canadian Centre for Activity and Aging. This community-based program educates older adults about the importance of exercise and provides them with experience in developing an exercise routine, which in turn motivates them to continue their exercise.

PURPOSE: To determine exercise adherence at 12-month follow-up in previously sedentary older adults.

METHODS: 173 previously sedentary but healthy participants (mean age 70.4 ± 5 years; 111 females, 62 males) were recruited at five sites across Canada and participated in an 8-week program where each week they attended two exercise sessions and one education session led by a GFAL-trained facilitator. Post-program, participants were encouraged to continue their exercise routine. At 12 months, participants were asked if they were currently exercising according to a definition that reflected the current exercise guidelines for older adults, with responses also reflecting the short form exercise stages of change questionnaire.

RESULTS: 149 participants (86%) remained in the study at 12 month follow-up (mean age 72.1 ± 5 years; 92 females, 57 males). 64% (n=95/149) reported currently meeting the exercise guidelines for older adults. 95% of the sample (n=141) reported participating in exercise, but not necessarily meeting the guidelines. 52% of older adults indicated they were in the maintenance stage of exercise behaviour, 12% were in the action stage, and 23% were in the preparation stage.

CONCLUSIONS: This short-term community-based 8-week intervention was effective in increasing the exercise adherence in community-dwelling older adults above rates commonly observed in the literature.Supported by CIHR.

614 MAY 30 4:15 PM - 4:30 PM

Evaluation Of Inactive Adults’ Ability To Maintain A Moderate-intensity Walking Pace

David A. Rowe, FACSM1, Minsoo Kang, FACSM2, Rona Sutherland1, Elizabeth A. Holbrook3, Tiago V. Barreira4, Moira Watson1. 1University of Strathclyde, Glasgow, United Kingdom. 2Middle Tennessee State University, Murfreesboro, TN. 3Roanoke College, Roanoke, VA. 4Pennington Biomedical Research Center, Baton Rouge, LA.

(No relationships reported)

Current physical activity guidelines emphasize the moderate intensity threshold, and recognize the additional health benefits of higher intensities. However, walking interventions rarely monitor or manipulate intensity, and often result in minimal health benefits despite increasing walking volume (steps/day). Consequently, an examination of self-paced walking intensity in inactive adults is warranted, as well as methods to regulate walking intensity in this population.

PURPOSE: To determine self-selected walking pace in currently inactive adults and investigate the efficacy of auditory stimuli to regulate moderate intensity walking.

METHODS: Currently inactive adults (N=25; 76% female; age=34±13 yr; height=1.65±0.10 m; weight=77.55±21.52 kg; BMI=28.58±7.48 kg/m2) completed a treadmill walking trial at 2.7 mph (moderate intensity), during which cadence and steady-state VO2 were measured. Two overground 10-min trials were then completed: a self-paced “brisk” walk (Trial 1) and a moderate-paced walk (≈3MET; Trial 2) in which cadence was prompted by a clip-on metronome matched to the treadmill cadence. Data were analyzed using RM t-test, Cohen’s d, Bland-Altman plot, and one-way RM ANOVA.

RESULTS: Mean energy expenditure and cadence during the treadmill trial were 3.88±0.53 METs and 114±8 steps/min. During self-paced walking (Trial 1) cadence was 124±8 steps/min (range = 106-146). Cadence during metronome-paced walking (Trial 2) was slower for all participants (114±8 steps/min; range = 100-131; p < .05, d = 1.23). From the Bland-Altman plots, 95% of participants walked within ±3 steps/min of the metronome cadence, and remaining participants were within ±10 steps/min. There were no significant differences (p > .05) among the minute-by-minute cadences across the 10 min of either condition.

CONCLUSIONS: Energy expenditure during a 2.7 mph treadmill walk was higher than the expected 3 MET. Inactive adults walk at a higher cadence during self-paced “brisk” walking, compared to walking at a metronome-guided moderate pace. While the natural walking pace of inactive adults appears to be at an intensity known to produce health benefits, and can be maintained for bouts of 10 minutes, the use of auditory feedback is an effective method for prompting walking at a prescribed intensity in inactive adults.

615 MAY 30 4:30 PM - 4:45 PM

Efficacy Of A Student Led, Community-based Falls Prevention Program

Cheryl Der Ananian1, Melanie Mitros2, Matthew Buman1. 1Arizona State University, Phoenix, AZ. 2Arizona Living Well Institute, Apache Junction, AZ.

(No relationships reported)

PURPOSE: Current guidelines suggest the use of multi-factorial fall prevention programs (FPPs) that include lower-extremity strength and balance exercises to prevent falls in community-dwelling older adults; however, the effectiveness of sustainable, low cost, community-based FPPs is limited.

METHODS: This 24-week quasi-experimental study examined the efficacy of a community-based, multi-component exercise plus education FPP (Stay in Balance, [SIB]) delivered by allied healthcare students. All participants initially received the 12-week SIB program and participants were non-randomly assigned at baseline to either continue the SIB exercise program at home or as a center-based program for an additional 12 weeks. Adults age 60 and older (n=69) at risk of falling (fall history or 2+ fall risk factors) were recruited to participate. The primary aim was to evaluate time and group-by-time effects of the SIB program on physical performance [(Timed Up & Go (TUG)]. Secondary aims were to examine time and group- by- time changes in functional balance [Berg Balance Scale (BBS)] and muscular strength. Mixed effects repeated measures using SAS Proc Mixed were used to examine group, time and group by time effects. Non-normally distributed outcome variables were log-transformed.

RESULTS: After adjusting for age, gender and body mass index, TUG scores, improved significantly over time (F(2,173) = 8.92, p=0.0; T0 - T2 diff = 1.2 [1.0]). Berg Balance Scores (F(2,173) = 29.0, p<0.0001; T0 - T2 diff = 4.96 [0.72]), chair stands (F(2,171) = 10.17, p<0.0001; T0 - T2 diff = 3.1 [0.7]) and arm curls (F(2,3.61) = 12.7, p<0.02; T0 - T2 diff = 2.7 [0.6]) also all improved significantly over time. There were no significant group or group- by- time effects observed for any of the outcomes.

CONCLUSION: The SIB program improved falls risk factors including physical performance, functional balance, and muscular strength. Findings suggest that having participants continue to perform strength and balance exercises at home after completion of a center-based FPP program is an effective way to maintain changes in physical functioning and balance parameters.

Supported by the 2009 ACSM Foundation Research Grant and 2009 ASU GPSA award.

B-68 Free Communication/Slide - Respiratory

MAY 30, 2012 3:15 PM - 5:00 PM

ROOM: 2007

616 Chair: Hans C. Haverkamp. Johnson State College, Johnson, VT.

(No relationships reported)

617 MAY 30 3:15 PM - 3:30 PM

Prevalence of Exercise Induced Desaturation in Highly Endurance Trained Men at Sea Level

Robert F. Chapman, FACSM1, Courtney Zimmerman1, David A. Tanner1, Timothy P. Gavin, FACSM2, Craig A. Harms, FACSM3, Joel M. Stager1. 1Indiana University, Bloomington, IN. 2East Carolina University, Greenville, NC. 3Kansas State University, Manhattan, KS.

(No relationships reported)

It has been reported that 52% of highly endurance trained men with VO2max > 68 ml/kg/min demonstrate exercise induced desaturation (SaO2 ≤ 91%) during heavy exercise (Powers et al, 1988). However, this often-cited prevalence rate comes from a single study using a cohort of 25 men who performed maximal cycle ergometry. As SaO2 at VO2max is reported to be significantly lower during treadmill versus cycle ergometry exercise in the same subjects (Gavin & Stager, 1997), we hypothesized that the prevalence of desaturation would be greater than previously reported in a larger cohort of highly endurance trained men during treadmill exercise.

PURPOSE: This study quantified the prevalence of arterial desaturation in highly endurance trained men during maximal treadmill exercise.

METHODS: Data from 124 male distance runners with VO2max > 60 ml/kg/min (range 60.3 - 84.7 ml/kg/min) were retrospectively examined from previously published studies completed in the Indiana University Bloomington Human Performance Laboratory. Runners completed a constant speed, progressive grade treadmill exercise test to volitional exhaustion, and SaO2 was measured in all subjects using the same oximeter (HP 47201A). Arterial desaturation (AD) was defined as SaO2 ≤ 91% during the final minute at maximal exercise.

RESULTS: With increasing VO2max, the prevalence of AD increased (biserial correlation rb = 0.99, p<0.01). AD prevalence for VO2max of 60.0 - 64.9 ml/kg/min, 12 of 23 subjects, 52%; for VO2max of 65.0 - 69.9 ml/kg/min, 23 of 36 subjects, 61%; for VO2max of 70.0 - 74.9 ml/kg/min, 25 of 39 subjects, 64%; for VO2max of ≥75.0 ml/kg/min, 17 of 24 subjects, 71%. Compared to the established prevalence and criteria for arterial desaturation in highly trained cyclists (52% of men with VO2max > 68 ml/kg/min), a significantly larger percentage of our runners desaturated during maximal treadmill exercise (55 of 79, or 71%; χ2=9.83, p<0.01).

CONCLUSION: These results indicate that the prevalence of exercise induced desaturation in highly trained men during maximal treadmill exercise is greater than has been previously suggested, with the greatest prevalence of desaturation associated with the highest values for VO2max. This suggests the higher cardiac outputs with increasing VO2max may play a primary role in exercise induced desaturation.

618 MAY 30 3:30 PM - 3:45 PM

Exercise-induced Arterial Hypoxemia And Respiratory Mechanics In Young Healthy Women

Paolo B. Dominelli, Glen E. Foster, Giulio S. Dominelli, William R. Henderson, Michael S. Koehle, Donald C. McKenzie, A William Sheel. University of British Columbia, Vancouver, BC, Canada.

(No relationships reported)

Many young adult male athletes with a high maximal O2 consumption (VO2max) show exercise-induced arterial hypoxemia (EIAH). In women, EIAH may occur at submaximal exercise intensities and at lower fitness levels, but this is controversial. Greater EIAH in women may be attributed to their increased mechanical constraints to ventilation owing to smaller airway diameters.

PURPOSE: To determine if women with varying fitness levels develop EIAH and the relationship to mechanical constraints to ventilation.

METHODS: Subjects (n=20, mean±SE; VO2max =48±2, range 36-61 ml·kg-1·min-1) completed a step-wise maximal test on a treadmill. Arterial blood gases (PaO2), corrected for esophageal temperature, and oxyhemeglobin saturation (SaO2) were measured at rest and during the last 30 s of each exercise stage. Pressure-volume loops were obtained using an esophageal balloon-tipped catheter. Expiratory flow limitation (EFL) was determined by superimposing tidal flow-volume loops on the maximum expiratory flow-volume curve. EIAH groups were classified as absent (ΔPaO2<10mmHg), mild (ΔPaO210-20mmHg) or severe (ΔPaO2>20mmHg).

RESULTS: All groups were similar with respect to age, height, weight, forced vital capacity and resting PaO2. Twelve subjects developed mild or severe EIAH and seven subjects showed EFL (range 15-45% of tidal volume). Maximal exercise PaO2 was related to A-aDO2 (r2=0.84, P<0.001) and absolute VO2max (r2=0.28, P=0.02) but not relative VO2max (r2=0.14, P=0.1). At maximal exercise, compared to the non-EIAH group, the mild and severe groups had significantly lower PaO2 (95±3 vs. 82±2 and 76±2 mmHg) and SaO2 (96±0.5 vs. 93±0.5 and 92±1 %) and a greater A-aDO2 (19±2 vs. 28±2 and 35±2 mmHg), respectively (P<0.05). Three of the 8 mild group and 4/4 of the severe group developed EIAH at a submaximal VO2 (range 56-85% V. O2max). Six of the 7 women displaying EFL developed EIAH (PaO2 at VO2max 73-87 mmHg). Tidal esophageal pressure swings were greater in the severe group compared to the mild or non-EIAH groups (58±5 vs. 48±3 and 42±3 cmH2O, P=0.027, respectively).

CONCLUSION: Healthy women with a wide range of aerobic fitness levels develop EIAH at maximal and submaximal exercise intensities. Mechanical ventilatory constraints are related to EIAH in women, but are not the exclusive cause. Funding: NSERC

619 MAY 30 3:45 PM - 4:00 PM

Accuracy of Non-invasive Estimates of Dead Space/Tidal Volume Ratios During Exercise in Morbidly Obese Subjects

Gerald S. Zavorsky1, Vipa Bernhardt2, Allison M. Straub1, Kaleen M. Lavin1, Tony G. Babb, FACSM2. 1Marywood University, Scranton, PA. 2University of Texas Southwestern Medical Center, Dallas, TX.

(No relationships reported)

The measurement of the physiologic dead space/tidal volume ratio (VD/VT) is a useful indicator of gas exchange that requires an invasive arterial PCO2 (PaCO2) measurement for its calculation.

PURPOSE: To determine the accuracy of non-invasive estimates of VD/VT based on end-tidal PCO2 (PETCO2) in obese subjects.

METHODS: 38 morbidly obese subjects (50 BMI) underwent a ramped exercise test to exhaustion. Mixed expired CO2 (PECO2) and PETCO2 were determined simultaneously with arterial blood gases (radial arterial catheter) at rest, minute 4 (submax) and at peak exercise. VD/VT was calculated using VD/VT = (PaCO2 - PECO2)/PaCO2. Estimates of VD/VT were calculated using either PETCO2 alone (VD/VT[ET]) or an estimated PaCO2 derived from Jones et al. (VD/VT[J], J Appl Physiol 1979) in place of PaCO2. Mean differences between actual and estimated VD/VT values were analyzed with paired t-tests.

RESULTS: At rest, mean values for actual VD/VT and estimated VD/VT[ET] and VD/VT[J] were not different: 0.37 (0.06) for all [(mean (SD)]. At submax and peak exercise, VD/VT[ET] was significantly higher than actual VD/VT (submax: VD/VT = 0.23 (0.05) vs VD/VT[ET] = 0.27 (0.03), p < 0.01; peak: VD/VT = 0.20 (0.06) vs VD/VT[ET] = 0.25 (0.03), p 0.05; peak: VD/VT[J] = 0.19 (0.05), p > 0.05).

CONCLUSION: While mean VD/VT at rest in this cohort of obese subjects was higher than normal (normal: 0.28 - 0.35), it showed the same decrease during exercise (normal at max: < 0.21). Thus, gas exchange in obese individuals is impaired at rest but improves during exercise. VD/VT[ET] overestimated actual VD/VT during exercise. VD/VT[J] accurately estimated VD/VT and thus could be used as a non-invasive alternative during cardiopulmonary exercise tests in obese subjects.

620 MAY 30 4:00 PM - 4:15 PM

Pulmonary Diffusing Capacity for Nitric Oxide is Related to Marathon Finishing Time

Kaleen M. Lavin, Allison M. Straub, Kathleen A. Uhranowsky, Gerald S. Zavorsky. Marywood University, Scranton, PA.

(No relationships reported)

Pulmonary diffusing capacity for nitric oxide (DLNO), measured at rest, can predict aerobic capacity (Acta Physiol, 2010, 198; 499-507). Since DLNO is a simple, time-efficient measurement requiring minimal effort, it may also be a good performance predictor in endurance events.

PURPOSE: (1) to define the relation between DLNO and marathon finishing time, and between DLNO and aerobic capacity; (2) to evaluate the accuracy of DLNO in predicting aerobic capacity and marathon finishing time relative to that of pulmonary diffusing capacity for carbon monoxide (DLCO).

METHODS: Prior to the 2011 Steamtown Marathon (Scranton, PA), 28 runners [age = 37 (SD) (9) years, weight = 70 (13) kg, height = 173 (9) cm, percent body fat = 17 (7) %] completed a test battery that included measurement of DLNO and DLCO at rest, and a graded exercise test to determine aerobic capacity. One to three weeks later, all runners completed the marathon (range: 2:22:38 to 4:48:55). Linear regressions determined correlations between finishing time and a variety of anthropometric characteristics, resting lung function variables, and exercise parameters.

RESULTS: Whereas both DLCO and DLNO were predictive of finishing time over the full range of finishers, DLNO (mL/min/mmHg/m2) showed a stronger coefficient of determination (r2 = 0.30, SEE = 33.4 min, p < 0.01) compared to DLCO. This pattern was stronger in runners meeting Boston Marathon qualification standards (r2 = 0.74, SEE = 11.8 min, p < 0.01). In non-qualifiers, neither DLNO nor DLCO predicted marathon finishing time. The fastest treadmill velocity sustained for one minute during the graded exercise test was most predictive of marathon finishing time in the non-qualifiers.

CONCLUSION: DLNO is performance-limiting only in Boston Qualifiers. This suggests that alveolar-capillary membrane conductance is a limitation to performance in faster runners. Additionally, DLNO predicts marathon finishing time and aerobic capacity more accurately than DLCO.

621 MAY 30 4:15 PM - 4:30 PM

The Effect of Aerobic Interval Training on Pulmonary Diffusing Capacity

Joseph M. Flaherty, James M. Smoliga, Kathleen A. Uhranowsky, Gerald S. Zavorsky. Marywood University, Scranton, PA.

(No relationships reported)

The lungs, unlike the heart and peripheral skeletal muscle, are said to be inadaptable with endurance training. However, since pulmonary diffusing capacity for nitric oxide (DLNO) is related to aerobic capacity (Acta Physiol, 2010, 198; 499-507), then high intensity aerobic interval training (HIT) could improve DLNO via the improvement in aerobic capacity.

PURPOSE: To investigate whether HIT in the short term improves DLNO.

METHODS: Twenty eight apparently healthy sedentary females [age 32 (SD) (10) yrs, weight 63 (14) kg] were randomly assigned to either a control group (sedentary behavior) or a HIT group (40-min cycling 3x per wk at about 85% heart rate reserve (HRR) for 6 weeks, about 250 kcal per session). Both groups performed pre and post procedure testing.

RESULTS: Aerobic capacity increased by +0.15 (0.17) L/min in the HIT group (p < 0.01) and +0.16 (0.25) L/min in the control group (p = 0.04). However, peak power output improved by +15 W more in the HIT group compared to the control group (p < 0.01). There was no relation between the change in aerobic capacity (L/min) with the change in DLNO (p > 0.05), or, the change in peak power output with the change in DLNO (p > 0.05).

CONCLUSION: The 8% increase in aerobic capacity with training was not sufficient to elicit an improvement in DLNO. It is likely that subjects in the control group did not fully abide to maintain their sedentary lifestyle during the testing period and this may have influenced the results.

622 MAY 30 4:30 PM - 4:45 PM

Effect of Abdominal Binding on Cardiorespiratory Function during Exercise in Paralympic Wheelchair Rugby Players

Christopher R. West1, Ian G. Campbell2, Vicky L. Goosey-Tolfrey3, Lee M. Romer, FACSM2. 1University of British Columbia, Vancouver, BC, Canada. 2Brunel University, Uxbridge, United Kingdom. 3Loughborough University, Loughborough, United Kingdom.

(No relationships reported)

Spinal cord injury (SCI) causes a lesion-dependent impairment in cardiorespiratory function that may limit exercise capacity. Abdominal binding improves resting cardiorespiratory function in individuals with cervical SCI. However, no study has evaluated the ergogenic effects of abdominal binding during exercise in this population.

PURPOSE: We asked whether abdominal binding enhances cardiorespiratory function during exercise in highly-trained athletes with cervical SCI.

METHODS: Eight GB Paralympic wheelchair rugby players with traumatic cervical SCI (C5-C7) completed three experimental trials in two randomised conditions (bound and unbound). During trial one, participants were assessed for respiratory muscle function (gastric [Pga], esophageal [Pes], and transdiaphragmatic [Pdi] pressure), operating lung volumes (end-expiratory lung volume [EELV] and end-inspiratory lung volume [EILV]), and cardiorespiratory responses during incremental sub-maximal treadmill propulsion (5 W every 4 min). In trials two and three, peak cardiorespiratory responses were obtained during a maximal incremental treadmill protocol (0.2% gradient every 40 s) and a maximal 4-min push in the field, respectively.

RESULTS: In trial one, binding increased end-expiratory Pga and Pdi (p<0.01), and reduced EELV (p=0.017), EILV (p=0.035) and the slope of the heart rate-oxygen uptake relationship (p=0.026). In trial two, binding increased peak oxygen uptake (1.43 ± 0.35 vs. 1.29 ± 0.33 L/min) and reduced peak blood lactate concentration (3.8 ± 1.0 vs. 4.6 ± 1.2 mM). In trial three, binding increased push distance (718 ± 82 vs. 699 ± 78 m) and reduced peak blood lactate concentration (6.8 ± 1.8 vs. 7.9 ± 2.0 mM). Peak oxygen uptake in the laboratory correlated with the distance covered during the maximal 4-min push (r=0.57, p=0.034), suggesting that the improvement in field-based exercise performance with binding was underpinned by an improvement in aerobic capacity.

CONCLUSION: Abdominal binding provides a simple, easy-to-use tool that can be used to enhance cardiorespiratory function during exercise in highly-trained athletes with cervical SCI.

Supported by UK Sport

623 MAY 30 4:45 PM - 5:00 PM

Is Dynamic Linearity A Consistent Feature Of Vo2 Kinetics In The Moderate-Intensity Domain?

Matthew D. Spencer, Juan M. Murias, John M. Kowalchuk, Donald H. Paterson, FACSM. University of Western Ontario, London, ON, Canada.

(No relationships reported)

Whether moderate-intensity exercise (MOD) transitions of different magnitudes yield similar pulmonary O2 uptake profiles (VO2p kinetics) within an individual (i.e., dynamic linearity) remains unclear. Additionally, the precise mechanism(s) responsible for regulating VO2p kinetics remain elusive, though recent studies support an intra-individual O2 delivery dependence/independence threshold. Insights into the balance between local muscle O2 delivery and O2 utilization can be gleaned from the ratio of NIRS-derived muscle deoxygenation (Δ[HHb])-to-VO2 to determine whether O2 delivery may constrain VO2p kinetics.

PURPOSE: To compare the VO2p and Δ[HHb] responses to 5 discrete MOD step increases in work rate (WR).

METHODS: Healthy males (n = 14; 24±5 yrs) each completed 4-8 repetitions of leg cycling MOD transitions from 20W (6min) to 6min at 50W, 70W, 90W, 110W and 130W. VO2p and Δ[HHb] responses were modeled as a mono-exponential; responses were then scaled to a relative % of the respective response (0-100%). The transient Δ[HHb]/VO2p ratio was calculated as the average Δ[HHb]/VO2 during the 20-120s period of the on-transient.

RESULTS: When considered as a single group, neither the phase II τVO2p (27±9, 26±11, 25±10, 27±14, 29±13s for 50-130W transitions, respectively) nor the Δ[HHb]/VO2 ratio (1.04±0.13, 1.10±0.13, 1.08±0.07, 1.09±0.11, 1.09±0.09, respectively) were affected by WR (p>0.05); yet the VO2 gain (G; ΔVO2/ΔWR) increased with increasing WR transitions (8.6±1.3a, 9.1±1.2a,b, 9.5±1.0b, 9.5±1.0b, 9.9±1.0c mL·min-1·W-1; p<0.05 for a, b, c). When subjects were stratified into two groups (fast (n=6), τVO2p130W < 25s < τVO2p130W, slow (n=8)), progressively greater τVO2p values were observed in the slow (p<0.05) but not fast (p>0.05) group. The increasing G persisted (p<0.05) and did not differ between groups (p>0.05). Finally, the Δ[HHb]/VO2 ratio was smaller (p<0.05) in fast vs. slow, but was unaffected by WR.

CONCLUSION: Larger magnitude MOD transitions yielded slower adjustments of VO2p compared to smaller magnitude MOD transitions in those with slow VO2p kinetics; yet, the progressive slowing does not appear to be a result of progressively poorer O2 delivery. Larger magnitude MOD transitions appear to require a greater G, regardless of τVO2p.

Supported by NSERC

C-17 Free Communication/Slide - Endocrine

MAY 31, 2012 8:00 AM - 9:45 AM

ROOM: 2014

624 Chair: Serge von Duvillard, FACSM. Norwegian School of Sport Sciences, Oslo, Norway.

(No relationships reported)

625 MAY 31 8:00 AM - 8:15 AM

Effects of Menstrual Cycle Phase on Glucose and Glucoregulatory Responses to Prolonged Exercise.

Robert R. Kraemer, FACSM1, Michelle Francois1, Jennifer R. Worley1, Sharon N. Rogers1, V. Daniel Castracane2. 1Southeastern Louisiana University, Hammond, LA. 2Texas Tech University Health Sciences Center, Odessa, TX.

(No relationships reported)

Amylin, a beta-cell peptide, works in combination with insulin to regulate blood glucose levels by controlling the influx of glucose into the bloodstream and preventing hyperglycemia. Glucoregulatory hormones are important to meet metabolic demands of moderate-intensity exercise during exercise and recovery. Increases in both estrogen and progesterone, as seen in the midluteal phases of the menstrual cycle, can increase glycogen storage in muscle and liver; estrogen will reduce hepatic gluconeogenesis which affects circulating insulin.

PURPOSE: To determine the effect of estrogen/progesterone levels on plasma amylin, insulin, and glucose responses to prolonged (90 min) treadmill exercise. Thus, we hypothesised that menstrual cycle stage would affect glucoregulatory hormone responses to continuous physical activity.

METHODS: Five healthy young women (mean±SD, 24.6±5.1y, 67.4±14.4kg) were monitored for 2 months to determine menstrual cycle length. Subjects completed a preliminary session to determine exercise workloads. In randomized fashion, subjects in an overnight fasted state, completed a control trial (no exercise) and two 90-min exercise trials at 60% VO2max, one during the early follicular phase (EFX) and the other during the midluteal phase (MLX) of their menstrual cycle. Blood samples were analyzed at rest, during exercise (54 and 90 min), and post-exercise (20 min).

RESULTS: There was a significant (p < 0.05) effect for time and time × trial for glucose with greater glucose levels after 54 min of exercise in the EFX trial than the same time point in the control trial [89.2±4.1 vs. 96.5.48 mg/dL], but no difference between the MLX and control trial. Although there was a time effect (p < 0.05) for insulin with values for EFX and MLX declining from pre-values [4.31±2.41 and 5.68±4.06] to 90 min exercise [2.87±1.55 and 3.37±2.41 μU/mL, respectively], there was no time × trial interaction. There was no time effect or time × trial interaction for amylin with amylin values with values for EFX and MLX declining from pre-values [20.12±14.2 and 15.18±8.65] to 90 min exercise [15.32±10.19 and 14.14±7.43 pM, respectively].

CONCLUSIONS: Data suggest that although stage of the menstrual cycle affects blood glucose responses to prolonged submaximal exercise, it does not affect insulin and amylin responses.

626 MAY 31 8:15 AM - 8:30 AM

Moderate Intensity Walking and Blood Glucose Control in Women with Gestational Diabetes Mellitus

Dawn P. Coe, Jo M. Kendrick, Bobby C. Howard, David R. Bassett, Jr., FACSM, Dixie L. Thompson, FACSM, Scott A. Conger, Jennifer D. White. University of Tennessee, Knoxville, TN.

(No relationships reported)

It is recommended that pregnant women accumulate 150 minutes per week of moderate intensity activity. Research has shown a beneficial effect of walking on glucose control in women with gestational diabetes mellitus (GDM). These studies incorporated low intensity walking and glucose control was limited to one hour post exercise.

PURPOSE: To determine the effect of postprandial moderate intensity walking on glucose control in women with GDM.

METHODS: Subjects were eight women with GDM, treated by diet with no medications and no contraindications to exercise. Each woman wore a continuous glucose monitoring system (CGMS; Medtronics, Inc.) for five days. Two randomly assigned conditions were compared: 30 minutes of moderate intensity treadmill walking (80 m·min-1; WALK) versus 30 minutes of sitting (CON). The CGMS was inserted on Day 1. On Day 2, subjects ate a fixed carbohydrate meal (60 g) after a two hour fast and were asked to perform one of the conditions (WALK or CON) thirty minutes after finishing the meal. No assessments were completed on Day 3. Day 4 was identical to Day 2 except the subjects experienced the condition they did not complete on Day 2 (WALK or CON). On Day 5, the CGMS was removed. Means and Area Under the Curve (AUC) for glucose were calculated and analyzed using paired t-tests.

RESULTS: Thirty minute postprandial glucose (baseline) was not different between the WALK and CON conditions (116.8 ±8.7 mg/dL vs. 118.6±16.7mg/dL). Immediate post treatment glucose was lower in the WALK condition compared to CON (87.0±6.6 mg/dL vs. 120.7±13.4 mg/dL; P<0.01). AUCs for glucose were significantly different on the WALK day compared to the CON day for up to three hours following treatment (Hour1 94.8±4.0 vs. 116.8±12.9;P=0.001, Hour2 182.9±9.7 vs. 215.4±22.3;P=0.003, Hour3 274.9±20.8 vs. 309.5±31.3;P=0.018). There was a trend towards differences in glucose AUCs between the WALK and CON conditions in hours four through six post treatment (Hour4 369.3±33.9 vs. 408.1±42.5, P=0.058; Hour5 458.5±47.6 vs. 509.4±57.2, P=0.057; Hour6 544.8±60.0 vs. 607.6±72.4, P=0.053).

CONCLUSIONS: Moderate intensity activity induces greater postprandial glucose control compared to sedentary activity. Consistent participation in moderate intensity activity may be used as an effective adjunctive therapy for the treatment of GDM.

627 MAY 31 8:30 AM - 8:45 AM

Short, Frequent Bouts Of Activity Reduce Glucose Excursions And Insulin Concentrations In Obese Individuals

Michael E. Holmstrup1, Timothy J. Fairchild2, Stefan Keslacy3, Ruth Weinstock4, Jill A. Kanaley, FACSM5. 1Delaware State University, Dover, DE. 2Murdoch University, Perth, Australia. 3Syracuse University, Syracuse, NY. 4SUNY Upstate Medical University, Syracuse, NY. 5University of Missouri, Columbia, MO.

(No relationships reported)

Sedentary behavior is thought to negatively influence insulin sensitivity, and may impact metabolic function, regardless of adherence to general physical activity guidelines. Long bouts of exercise may be difficult to combine with a busy lifestyle.

PURPOSE: To determine the effect of physical activity comparing 1 h continuous exercise vs. intermittent exercise combined with frequent meal consumption on glucose excursions and insulin secretion in healthy, obese individuals.

METHODS: Eleven healthy, obese subjects (>30 kg/m2) underwent three 12 h study days including sedentary behavior (SED), exercise ((EX) 1 h morning exercise, 60-65% VO2 max), and physical activity ((PA) 12 hourly, intensity-matched 5-minute bouts), where each subject completed all three conditions. Meals were provided every 2 h, and were identical across conditions. Blood was sampled every 10 min for 12 h. Baseline and integrated area under the curve (AUC) for serum glucose, insulin and c-peptide concentrations, as well as insulin pulsatility were determined.

RESULTS: No significant differences in baseline glucose, insulin or c-peptide concentrations across study conditions were observed (P>0.05). Glucose AUC for 12 h and 2 h were significantly different across study days, with AUC attenuated with PA compared to the EX condition (P<0.05). The 12 h incremental insulin AUC was reduced by PA compared to SED behavior(173,985±3556.8 v. 227,352±4581.2 pmol/L*min for 12h, respectively; P<0.05). Similarly, a significant main effect of condition in the 2 h incremental insulin AUC was found, with PA reducing AUC compared to SED (P<0.05), but no differences between the EX and SED conditions. A significant reduction in 2 h c-peptide AUC was demonstrated with EX and PA compared to the SED condition (P<0.05). There were no significant differences noted in insulin secretory parameters across experimental conditions.

CONCLUSION: Short bouts of physical activity throughout the day attenuate the glucose response and reduce insulin concentrations compared to 1 h of morning exercise followed by sedentary behavior. Reductions in insulin levels with intermittent physical activity may be due to augmented insulin clearance, as no differences in insulin secretion were found.

628 MAY 31 8:45 AM - 9:00 AM

Race and Parity Influence Relationships Among Fitness, Central Fat Accumulation, and Insulin Sensitivity

Katherine H. Ingram, Barbara A. Gower, Gary R. Hunter, FACSM. University of Alabama at Birmingham, Birmingham, AL.

(No relationships reported)

Fitness level and adiposity, particularly central adiposity, are both known to influence insulin sensitivity. It has been reported that both parity and race affect the accumulation of intra-abdominal adipose tissue (IAAT), but it is unknown whether these characteristics influence the relationships among IAAT, fitness level, and insulin sensitivity.

PURPOSE: To examine the influence of race and parity in the relationships among fitness level, central adiposity, and insulin sensitivity.

METHODS: We assessed VO2max, intra-abdominal adipose tissue (IAAT), SI, calculated from the minimal model method, and the HOMA index of insulin resistance in 212 overweight, premenopausal, non-Hispanic white (NHW) and African American (AA) women (age 34 ± 6.2; BMI = 27.5 ± 4.7) matched for age and BMI. Univariate ANOVA was used to examine differences in means from groups based on self-reported race and parity. Stepwise multiple regression was used to find the strongest predictors of insulin sensitivity among the groups. SI was log-transformed for normality for these analyses.

RESULTS: In all women, SI correlated with VO2max (r=0.19, p = 0.007), but not IAAT (r = -0.07, p= 0.33), when controlled for BMI and age. Non-parous women (n=89) were younger (31.3 ± 6.5 vs. 36.4 ± 5.1), had less IAAT (69.6 ± 31.4 vs. 85.4 ± 30.3), and a higher VO2max (29.5 ± 4.0 vs. 27.7 ± 3.6), but showed no difference in SI, when compared to parous women (n=114). Further stratified by race, NHW women were more insulin sensitive (3.5 ± 1.8 vs. 2.5 ± 1.9 [x 10-4 min-1/(μIU/ml)]), had a higher VO2max (29.2±4.0 vs. 27.6±3.6), and more IAAT (92.7±30.4 vs. 65.1 ± 25.9) than AA women. Among VO2max, IAAT, BMI, and Age, regression analyses revealed that VO2max is the strongest predictor of HOMA in non-parous NHW women (R2=0.17, p < 0.01), while IAAT is the strongest predictor of HOMA in both parous (R2=0.12, p < 0.05), and non-parous (R2=0.17, p < 0.01) AA women and is the strongest predictor of SI in parous (R2=0.07, p < 0.05), and non-parous (R2=0.20, p < 0.01) NHW women. BMI is the strongest predictor in parous AA women (R2=0.17, p < 0.01).

CONCLUSIONS: Our data demonstrates that the relationships among fitness level, central adiposity, and insulin sensitivity in women vary as a result of race and reproductive history.

629 MAY 31 9:00 AM - 9:15 AM

Glucose Metabolism In Wistar Rats At Different Ages: Effects Of Exercise Training

Ana Carolina Ghezzi, Lucieli Teresa Cambri, José Diego Botezelli, Rodrigo Augusto Dalia, Michel B. Araujo, Pedro Paulo Menezes Scarioti, Maria Alice Rostom Mello. São Paulo State University -UNESP, Rio Claro, Brazil.

(No relationships reported)

BACKGROUND: Studies have described the metabolic syndrome as an association between some disorders such as hiperinsulinemia, glucose intolerance, dyslipidemia, hypertension and obesity. It is known that aging can contribute to the development of signs of the metabolic syndrome. Objective: Evaluate glucose metabolism in Wistar rats of different ages, subjected or not to exercise training.

METHODS: The rats were evaluated at: two months Group I, four months Group II, six months Group III and twelve months Group IV of age. Additionally, one group Group V was subjected to exercise 4th to the 12th month of age and another Group VI, to the same exercise 4th to the 8th month of age. The training consisted of one hour of swimming with a workload 80% of the maximal lactate steady state attached to the thorax. We analyzed the glucose tolerance (GTT) as well as serum glucose in the fed state. Longitudinal soleus muscle slices weighing approximately 25-35 mg were incubated in Krebs-Ringer bicarbonate buffer enriched with glucose (5.5 mM, containing [3H] 2-deoxiglucose (0,5 μCi/mL)) for evaluation of muscle glucose uptake.

RESULTS: Serum Glucose: Groups I: 98±14a; Groups II: 109±8a; Groups III: 119±29a; Groups IV: 152±29b; Groups V: 140±24b; Groups VI: 150±18b. Area under the serum glucose curve: Groups I: 9768±3326a,c; Groups II: 10670±2094a,b,c; Groups III: 11205±1004a,c; Groups IV: 12314±1122b,c; Groups V: 8428±853a; Groups VI: 9433±1200a,c. Muscle glucose uptake: Groups I: 1.40±0.34; Groups II: 2.10±0.24; Groups III: 2.50±0.40; Groups IV: 1.96±0.54; Groups V: 2.43±0.24; Groups VI: 2.39±0.50. Different letters mean significance difference among the groups. ANOVA two-way with Newman Keuls post hoc.

CONCLUSION: Aging caused changes in the serum glucose concentrations and in the area under the serum glucose curve during the GTT, but glucose uptake by isolated soleus was unchanged. Physical training counteracted the aging-related alterations in the area under the serum glucose curve, because the animals in group V did not show glucose intolerance. In summary, aging brings glucose metabolism alterations in wistar rats and exercise training at controlled intensity can be beneficial in counteracting some of these alterations. Supported by FAPESP (proc 2010/12896-0).

630 MAY 31 9:15 AM - 9:30 AM

Effects Of Caloric Restriction Compared To Caloric Balance On The Response Of The IGF-I System

Paul C. Henning, Bradley C. Nindl, FACSM, Kevin R. Rarick, Dennis S. Scofield, Joseph R. Pierce, Michael J. Stanger, Harris R. Lieberman. U.S. Army Research Institute of Environmental Medicine, Natick, MA.

(No relationships reported)

Insulin-like growth factor-I (IGF-I) is a key regulator of metabolism during altered energy states. IGF-I declines during caloric restriction, but few data are available that provide resolution for IGF-I and IGF-I binding protein (BP) responses within the context of altered caloric composition.

PURPOSE: To examine the response of the IGF-I system and glucose concentrations during altered dietary intakes.

METHODS: A double-blind, placebo-controlled crossover design was used in which 25 men and women (24±1 yr) underwent 3, 48-hr experimental treatments with total caloric intakes and diet composition over the 48-hr as follows: 1) caloric restriction (CR) (321±8 kcal, 78/0/22), 2) carbohydrate diet condition (CHO) (4678±26 kcal, 98/2/0), and 3) carbohydrate-fat (CHO/F) diet condition (4694±118 kcal, 72/1/27). Blood was sampled for glucose, IGF-I (total and free) and IGFBPs1-4 using commercially-available immunoassays. Data were analyzed using repeated measures ANOVA with a Tukey HSD post-hoc test when appropriate and are presented as mean ± SE.

RESULTS: In response to caloric restriction, mean glucose concentrations were lower for CR (85 ± 2 mg/dl, p<0.05) compared to CHO (99 ± 2.6 mg/dl) and CHO/F (97 ± 2.3 mg/dl). Total IGF-I declined by 7% during CR (pre=516 ± 35 ng/ml, post=478 ± 34 ng/ml, p=0.051) compared to CHO (pre=515 ± 31ng/ml, post=533 ± 31 ng/ml) and CHO/F (pre=524 ± 37 ng/ml, post=510 ± 30 ng/ml). Free IGF-I decreased by 43% during CR (pre=1.9 ± 0.26 ng/ml, post=1.1 ± 0.23, p<0.05) compared to CHO (pre=1.8 ± 0.28ng/ml, post=1.7 ± 0.3 ng/ml) and CHO/F (pre=1.9 ± 0.28 ng/ml, post=1.6 ± 0.25 ng/ml). IGFBP-1 increased dramatically by 445% during CR (pre=11± 1.4ng/ml, post=59.9 ± 6.8, p<0.05) compared to CHO (pre=13 ±1.5ng/ml, post=35.5 ± 7.7) and CHO/F (pre=14.1 ± 1.7ng/ml, post=30.3 ± 4.9 ng/ml) with no changes for IGFBP-2, IGFBP-3 and IGFBP-4.

CONCLUSIONS: Our findings indicate free IGF-I decreases and IGFBP-1 increases during caloric restriction, but are not altered with isocaloric diets differing in carbohydrate and fat content. Changes in free IGF-I and IGFBP-1 (most likely influencing IGF-I bioavailability) are sensitive to caloric restriction, and their measurement may be valuable in monitoring responses to refeeding in those consuming suboptimal calories.

631 MAY 31 9:30 AM - 9:45 AM

Effect Of Chronic Hyperinsulinemia On Insulin Signaling And Mitochondria In Lean And Obese Human Myocytes

Melissa A. Reed1, Jill M. Maples2, Todd M. Weber2, Walter J. Pories2, Joseph A. Houmard, FACSM2, G Lynis Dohm2, Timothy P. Gavin, FACSM2. 1West Chester University, West Chester, PA. 2East Carolina University, Greenville, NC.

(No relationships reported)

PURPOSE: The purpose of this study was to determine if exposure to chronic hyperinsulinemia would down-regulate the insulin-signaling pathway in skeletal muscle myocytes from lean insulin sensitive and obese insulin resistant individuals. This study also examined the effects of chronic hyperinsulinemia on mitochondrial content and fatty acid oxidation.

METHODS: Insulin signaling, mitochondrial content and fatty acid oxidation were measured in myotubes pooled from lean insulin sensitive and obese insulin resistant individuals following a 4 day incubation of either low (80 pM) insulin or high (5000 pM) insulin.

RESULTS: Insulin signaling was not down-regulated due to chronic hyperinsulinemia in either group. Rather, AS160 was increased in the lean group after chronic hyperinsulinemia (low insulin: 0.973 + 0.325 vs. high insulin: 1.932 + 0.400 p<0.05). Complete oxidation of FA (FAO) was significantly reduced in the obese compared to lean group (lean FAO low insulin 0.532 + 0.044 vs. obese FAO low insulin 0.410 + 0.005, p< 0.05; lean FAO high insulin 0.571 + 0.036 vs. obese FAO high insulin 0.404 + 0.009 p < 0.05) independent of insulin incubation. In the current study, mitochondrial content was not different between the lean and obese groups for either insulin condition (lean low insulin COXIV protein 0.813 + 0.146 vs. obese low insulin COXIV protein 0.755 + 0.181; lean high insulin COXIV protein 0.792 + 0.120 vs. obese high insulin COXIV protein 0.684 + 0.091).

CONCLUSION: Chronic hyperinsulinemia increases insulin signaling in lean insulin sensitive myocytes compared to obese suggesting the obese exhibit a blunted response. Also, chronic hyperinsulinemia did not affect fatty acid oxidation or mitochondrial content in the lean or obese group but the obese group experienced dysregulated fatty acid metabolism independent of insulin suggesting an inherent defect in the obese compared to the lean group.

C-18 Free Communication/Slide - Exercise and Aging

MAY 31, 2012 8:00 AM - 9:45 AM

ROOM: 2016

632 Chair: Wojtek Chodzko-Zajko, FACSM. University of Illinois at Urbana-Champaign, Urbana, IL.

(No relationships reported)

633 MAY 31 8:00 AM - 8:15 AM

Exercise Dosing to Maximize Muscle Re-Growth in Older Adults

Kristina M. Vaughn, Edward K. Merritt, Craig Tuggle, Samuel L. Windham, Anna Thalacker-Mercer, Louis J. Dell’Italia, Marcas M. Bamman, FACSM. University of Alabama at Birmingham, Birmingham, AL.

(No relationships reported)

Although resistance training (RT) has shown the most promise among tested interventions to combat aging muscle atrophy, the optimal prescription to induce muscle re-growth (i.e. hypertrophy following atrophy) has yet to be identified. In our hands, the commonly recommended prescription for beginners of 3 d/wk moderate-high intensity RT generally leads to a blunted hypertrophic adaptation in 60-75 y vs. 20-35 y old adults, and over one-third of 60+ y adults fail to experience any hypertrophy at all.

PURPOSE: In an effort to optimize the RT prescription for older adults, we determined the muscle hypertrophy response to four different RT prescriptions of varying frequency and intensity.

METHODS: After 4 wk of moderate intensity pre-training, 70 adults 60-75 y were randomly prescribed 3x/wk high (H) intensity RT (HHH3); 2x/wk H (HH2); 2x/wk H separated by 1x/wk low (L) intensity (HLH3); or 1x/wk H + 1x/wk L (HL2) for 30 wk. DXA, MRI, and muscle biopsies were performed across time to assess changes in muscle mass and myofiber size.

RESULTS: Although analyses are ongoing, at the time of abstract submission a prescription × time intrxn (P<0.05) and post hoc testing revealed DXA-determined (n=58) improvements in lean mass occurred with all prescriptions but HL2, and gains were greatest in HLH3. A similar DXA intrxn (P<0.05) was noted in the leg compartment, with the greatest gains in HLH3. MRI-determined (n=56) adductor muscle size increased most (prescription × time, P<0.05) in HHH3 and HLH3; quadriceps muscle size increased in all prescriptions by mid-training but only HHH3 and HLH3 sustained the hypertrophy at 30 wk. Myofiber cross-sectional area results thus far on n=40 have not revealed prescription × time intrxns for type I or type II myofiber hypertrophy.

CONCLUSIONS: An important finding from this work is that differential responses in older adults (i.e. the degree of muscle re-growth) are detectable when varying the RT dose prescribed. Results appear to favor a 3 d/wk prescription that includes 2 d of H training interspersed by 1 d of L training. Overall this study supports the notion that exercise doses should be carefully titrated to provide the evidence base for prescription targeting specific outcomes of interest. SUPPORT: 5R01 AG017896.

634 MAY 31 8:15 AM - 8:30 AM

Sarcopenia Indices: Age- And Gender-related Differences In Body Composition, Strength, And Muscle Quality

Ashley A. Walter1, Trent J. Herda2, Pablo B. Costa3, Andrea M. Valdez1, Abbie E. Smith4, Kristina L. Kendall1, David H. Fukuda1, Jeffrey R. Stout1, Joel T. Cramer, FACSM5. 1University of Oklahoma, Norman, OK. 2University of Kansas, Lawrence, KS. 3California State University-San Bernardino, San Bernardino, CA. 4University of North Carolina-Chapel Hill, Chapel Hill, NC. 5Oklahoma State University, Stillwater, OK.

(No relationships reported)

Sarcopenia is the age-related loss of muscle and function. It is likely that losses in strength may occur prior to any detectible changes in lean mass. Muscle quality, a ratio of strength to lean mass, may be able to account for changes in both variables for early detection of sarcopenia.

PURPOSE: To examine age- and gender-related differences in body composition, strength, and muscle quality in older adults.

METHODS: 114 men and women (mean±SD age: 68.3±7.6 yrs; height: 167.7±9.3 cm; weight: 72.3±13.8 kg) age-stratified by decade (50s n=20; 60s n=51; 70s n=37; 80s n=7) completed a whole-body dual-energy x-ray absorptiometry (DEXA) scan for total body lean mass (LM), total body fat mass (FM), total leg LM (TLLM), dominant arm lean mass (DALM), appendicular lean mass (ALM), and SMI (ALM/ht2). Muscle strength (kg) was measured by handgrip dynamometry (HG) and leg press 1-RM (LP). Handgrip muscle quality (HGMQ) and lower-body muscle quality (LMQ) were expressed relative to DALM or TLLM. Ten separate two-way factorial ANOVAs (gender [men vs. women] × age [50s vs. 60s vs. 70s vs. 80s]) were used to compare mean values. An alpha of p≤0.05 was considered statistically significant for all comparisons.

RESULTS: For body composition, men in 50s, 60s, and 70s had greater DALM than 80s. LM, TLLM, and SMI in 50s, 60s, and 70s > 80s. Men were greater than women for LP, LM, TLLM, and SMI, while women > men for FM regardless of age, and DALM was greater for men than women in 50s, 60s, and 70s. FM or ALM did not change with age. For muscle strength, HG in 50s, 60s, and 70s > 80s for both genders and LP in 50s than 60s, 70s, and 80s for men and women. For muscle quality, HGMQ in 50s and 60s > 80s and LMQ in 50s > 80s for both genders and men had greater LMQ than women.

CONCLUSIONS: Body composition variables, such as DALM in men as well as LM and TLLM in both genders showed decrements later in the age span (8th decade). Strength variables, HG and LP, and muscle quality for the lower body (LMQ) exhibited decrements earlier in the age span (after the 5th and 6th decades). These findings tentatively supported the hypothesis that simple changes in body composition may not be sensitive enough to detect early losses in strength and muscle quality that are likely precursors to sarcopenia.

This study was funded by grants from Abbott Nutrition and the General Nutrition Corporation.

635 MAY 31 8:30 AM - 8:45 AM

The Relationship Between Physical Activity and VO2max in Healthy Seniors

Kara Boyd1, Dean Palmer1, Graeme Carrick-Ranson1, Naoki Fujimoto1, Sheryl Livingston1, Dan Creson1, James McLoughlin1, Jeff Hastings1, Benjamin Levine, FACSM2. 1Institute for Exercise and Environmental Medicine, Dallas, TX. 2UT Southwestern Medical Center, Dallas, TX.

(No relationships reported)

Increased physical fitness over a lifetime improves functional capacity, quality of life, and reduces cardiovascular risk in older (>60 years) adults. Establishing a relationship between exercise capacity, lifetime aerobic exercise frequency (d/wk) and intensity (number of mins/wk ≤ a given MET level) in older adults may provide important information to improve physical fitness in this population.

PURPOSE: The objective of this study was to determine whether maximal oxygen uptake (VO2max) is related to exercise frequency and intensity in older adults.

METHODS: We studied 91 (41% women) healthy, seniors (ages 68.3 ± 6.8) who had a consistent level of physical activity for at least the last 20 years. Individuals were classified into 4 groups via an extensive verbal exercise history into sedentary (<30 min of aerobic exercise 2 d/wk), Quad 2 (2-3 d/wk), Quad 3 (4-5 d/wk), and Quad 4 (≥5 d/wk and competing). VO2max was measured via the Douglas Bag method during a maximal treadmill test. Exercise intensity was measured using an accelerometer worn for 6 or 7 continuous days and analyzed for total minutes spent ≥3, 5, and 6 METs.

RESULTS: VO2max increased with exercise frequency (r = 0.78, p<0.001), and was greater in exercisers compared to sedentary individuals (graph). In all subjects there was a weak correlation (r=0.41, p<0.001) between VO2max and minutes spent ≥3MET. This relationship was strengthen with a 6 MET threshold (r = 0.71, p<0.001).

CONCLUSION: VO2max can be related to both lifelong training frequency and intensity; however training frequency and exercise above 6 METs seems to prove a strong stimulus for increasing VO2max in older adults.

636 MAY 31 8:45 AM - 9:00 AM

Osteopontin: A Complex Genetic Modifier Of Muscle Size And Muscle Damage.

Eric P. Hoffman1, Joseph Devaney1, Paul Thompson, FACSM2, Edward Zambraski3, Paul Visich4, Paul Gordon5, Heather Gordish-Dressman1, Linda Pescatello6, Richard Zoeller7, Niall Moyna8, Theodore Angelopoulos9, Priscilla Clarkson, FACSM10. 1Children’s National Medical Center, Washington, DC. 2Hartford Hospital, Hartford, CT. 3United States Army Research Institute of Environmental Medicine, Natick, MA. 4University of New England, Biddiford, ME. 5University of Michigan, Ann Arbor, MI. 6University of Connecticut, Storrs, CT. 7Florida Atlantic University, Davie, FL. 8Dublin City University, Dublin, Ireland. 9University of Central Florida, Orlando, FL. 10University of Massachusetts Amherst, Amherst, MA.

(No relationships reported)

Duchenne muscular dystrophy (DMD) is the most common muscle disease, and is caused by loss of dystrophin protein at the myofiber plasma membrane. Individual patients showed variability in onset of muscle weakness, and disease progression, suggesting that genetic modifiers (polymorphisms in other genes) may underlie clinical variability in muscle symptoms.

PURPOSE: A study of genetic modifiers of DMD was recently reported (Pegoraro et al. 2011). This research showed a promoter polymorphism of osteopontin (OPN, also called, SPP1; rs28357094) to be strongly associated with the severity of disease in two cohorts of DMD patients. We sought to query the role of the same polymorphism in muscle phenotypes in normal college-age volunteers.

METHODS: We studied the FAMuSS cohort (752 healthy Caucasian volunteers, young adults mean age 23.7 ± 5.7 yrs) (Thompson PD, Med Sci Sports Exerc. 2004;36:1132-9). Phenotypes studied included muscle size (MRI), strength, and response to supervised resistance training. We also studied an eccentric muscle damage cohort involving 157 young adults mean age 25.3 ± 5.4 yrs (Clarkson PM, J Appl Physiol 2005; 99: 564-9). Phenotypes studied included loss of muscle strength, increase in soreness, and rise in serum CK and myoglobin at timed intervals following the bout of eccentric elbow exercise.

RESULTS: The OPN rs28357094 polymorphism showed a strong association with multiple muscle phenotypes in women, but not men. In the FAMuSS cohort, the G allele was associated with 17% increase in upper arm muscle volume in women (F=13.11; p=3.55e-06), with this single polymorphism explaining approximately 5% of all variance in baseline muscle volume in females. In the eccentric damage cohort, the GG genotype was associated with 3-fold increased rise in serum creatine kinase levels at 10 days after the eccentric exercise bout relative to other genotypes. This polymorphism explained approximately 17% of all observed variance in CK levels after eccentric exercise, although the number of homozygotes for the G allele were few.

CONCLUSION: The ; rs28357094 osteopontin polymorphism appears to be one of the strongest genetic modifiers of muscle in both health and disease identified to date. The osteopontin gene is known to be estrogen responsive, and this may explain the sexual dimorphism in genotype effect.

637 MAY 31 9:00 AM - 9:15 AM

Older Adults Performance-based Physical Function (PF) Impacted Directly By Perceived PF And Indirectly By PA

Anne O’Brien1, Katherine Hall2, Rudy Valentine3, Ellen M. Evans, FACSM1. 1University of Georgia, Athens, GA. 2Durham VA Medical Center, Durham, NC. 3University of Illinois, Urbana, IL.

(No relationships reported)

Although not well characterized, limited data suggests that the perception of physical function (PF) is moderately associated with the performance of objectively measured PF tasks, in older adults. The results from physical activity (PA) interventions with older adults have produced equivocal results for changes in perception and performance of PF; some studies found improvements in perceived PF with no change in performance-based function. Alternatively other work has shown improvement in performance-based function with no improvement in perceived function. Moreover, an additional factor that has been gaining attention as a risk factor for disability in older adults is adiposity, which is also known to be impacted by PA. The relationship between adiposity and perception of PF has not been investigated.

PURPOSE: To determine the direct and indirect, through PA and adiposity (%Fat), influences of perceived physical function (PPF) on lower extremity physical function (LEPF) in older adults using a cross-sectional model.

METHODS: Older adults (n=325, 57% males, 71.74 ± 7.1 years, range 60-93 years) completed questionnaires of PPF (SF-36PF) and PA (CHAMPS, PASE), tasks to determine LEPF (8 foot up-and-go, 6 minute walk, 30 second chair stand), and were assessed for body composition via DXA. Path analysis was used to examine the proposed associations. The measures of LEPF were used to create a latent variable for function.

RESULTS: PPF, PA and %Fat were all independently related to LEPF (r range -0.28 to 0.55, all p < 0.05). The model revealed an excellent fit to the data (χ2 = 16.62, df = 6, p < 0.05; CFI=0.98; RMSEA [90% CI] = 0.07 [0.03-0.12]; SRMR = 0.03). PPF had significant direct effects on LEPF (β = .47), and significant indirect effects on LEPF via PA but not %Fat.

CONCLUSIONS: Older adults reporting higher levels of PPF had lower %Fat, higher levels of PA, and higher performance-based PF. Perceptions of PF directly impact performance-based PF. However, performance-based PF is also impacted indirectly by perceptions of PF through its association with PA. In addition to PA, interventions targeting adiposity and perceptions of PF may also improve PF in older adults.

638 MAY 31 9:15 AM - 9:30 AM

Changes in Peripheral and Central Blood Pressure following Regional Specific Exercise

Mitch VanBruggen1, Daniel Credeur2, Katherine L. Ham1, Conrad Earnest3, Jennifer L. Robbins1, Neil Johannsen3, William E. Kraus, FACSM1, Timothy S. Church3, Eric Ravussin3, Michael A. Welsch, FACSM2, Jason D. Allen1. 1Duke University Medical Center, Durham, NC. 2Louisiana State University, Baton Rouge, LA. 3Pennington Biomedical Research Center, Baton Rouge, LA.

(No relationships reported)

With advancing age there is an increase in large artery stiffness, which leads to a rise in myocardial work, decreased coronary perfusion, and a reduction in exercise tolerance.

PURPOSE: To determine differences between 4 wks of regional specific training (RSTS) versus aerobic exercise training (AET) on blood pressure and physical and functional performance.

METHODS: Subjects were ≥70yrs and scored between 218-490yrds on a 6 min walk test, without experiencing adverse responses. Subjects were randomized to AET (60 min/session; walking/biking at 50-85%HRR, 3 d/wk) or RSTS (60 min/session; 9 exercises specific to a primary muscle groups; 15 contractions/min starting at 40%MVC of muscle group of interest) for 4 wks. Applanation tonometry was used to calculate central blood pressures and pulse wave velocity (PWV). Physical function (senior fitness test (SFT)) and capacity (Time to Exhaustion (TTE) on GXT; Muscular Strength (Chest Press + Seated Row + Leg Press + Handgrip = TOT) were examined before and after 4 wks.

RESULTS: Groups were similar in number (RSTS=47, 14 men; AET=47, 16 men), age (RSTS:76±4.98; AET:76±4.78 yrs), weight (RSTS:78.79±15.03; AET:80.28±16.40Kg), and blood glucose (RSTS:112±16.53; AET:111± 21.83mg/dl). Training resulted in significant reductions in brachial (SBP: -2.79± 1.30, p=0.03; DBP: -2.48±0.77, p=0.002; MAP: -2.45± 0.95, p=0.01) and aortic BP (SBP: -3.31± 1.21, p=0.007; DBP: -2.77± 0.73, p=0.001; MAP: -2.84±0.89, p=0.002). Magnitude of reduction tended to be greater in the RSTS group for Brachial DBP (p=0.07), Aortic SBP (p=0.13) and DBP (p=0.10), and PWV (p=0.14). There were main effects for SFT (+11.01±0.86U, p=0.001), TTE (+62±17.14sec, p=0.001), and TOT (+37.72±4.90Kg, p=0.001). Finally, there was a group*time effect for TOT, with the RSTS having greater strength gains (p=0.001).

CONCLUSION: Four weeks of training, resulted in significant reductions in both brachial and aortic BP, with individuals in the RSTS group showing a tendency for more favorable hemodynamic changes. Moreover, those in the RSTS group had significant greater strength gains, albeit similar improvements in SFT scores and TTE, compared to AET.

Supported by 1RC1AG035822-01 and the Duke University Claude D. Pepper OAIC (AG0287) both from NIA to Dr. Jason D. Allen

639 MAY 31 9:30 AM - 9:45 AM

Are Sarcopenia And Sarcopenic Obesity Associated With Metabolic Risk Factors In Older Women?

Ricardo M. Lima1, Enivaldo P. dos Santos2, Luiz C. Júnior3, Marisete P. Safons1, André B. Gadelha1, Ricardo J. de Oliveira1. 1University of Brasília, Brasília, Brazil. 2Federal Institute of Piauí, Floriano, Brazil. 3University of Vale do Acaraú, Sobral, Brazil.

(No relationships reported)

Sarcopenia and Sarcopenic Obesity (SO) are linked to negative outcomes in the elderly but its association with metabolic risk is poorly investigated. In contrast, waist circumference is well accepted to predict metabolic risks.

PURPOSE: To examine the association between sarcopenia and SO with metabolic risk indexes in older women.

METHODS: A total of 100 volunteers (67.5±6.5 yrs) underwent body composition assessment using dual energy x-ray absoptiometry and had blood samples collected for subsequent laboratorial analyses for lipid profile, glucose metabolism and C-reactive protein. Sarcopenia was defined as an appendicular fat-free mass (AFFM) divided by height squared equal to or below 5.45kg/m2 while SO was classified based on the residuals of a regression of AFFM on height and fat mass, with the percentile 20th being the cutoff as proposed by Newman et al. (2003). Waist circumference and arterial blood pressure were also measured. Values were compared between those classified for sarcopenia or SO with those non classified and correlations were analyzed. Significance level was set at P<0.05.

RESULTS: Prevalence of sarcopenia and SO were respectively 12 and 20%. Waist circumference was positively correlated with blood pressure, glucose metabolism indexes, C-reactive protein, Triglycerides, VLDL cholesterol (r =0.25 to 0.48; all P<0.05), and negatively correlated with HDL cholesterol (r=-0.23; P<0.05). In contrast, AFFM relative to height squared was positively correlated with diastolic blood pressure, insulinaemia, HOMA score (r =0.21 to 0.45; all P<0.05), and those classified as sarcopenic presented a lower HOMA score when compared to nonsarcopenic (1.6±2.2 vs. 0.6±0.4; P<0.05). Regarding SO, although volunteers classified presented significantly higher fat mass (41.4±5.8 vs. 47.3±6.1%; P<0.05) and lower AFFM (15.5±1.9 vs. 13.4±1.6kg; P<0.05), it was not observed significant differences for none of the examined metabolic risk factors.

CONCLUSIONS: These findings support the association between waist circumference and metabolic risk factors in older women. In contrast, this study provides evidence that sarcopenia and SO are not associated with metabolic impairments in such population. Future studies are necessary to better elucidate these findings.

Supported by FAPDF Grant 193000555/2009

C-19 Free Communication/Slide - Osteoarthritis of the Lower Limb Joints

MAY 31, 2012 8:00 AM - 10:00 AM

ROOM: 2020

640 Chair: Jean L. McCrory, FACSM. West Virginia University, Morgantown, WV.

(No relationships reported)

641 Chair: Clare Milner, FACSM. University of Tennessee, Knoxville, TN.

(No relationships reported)

642 MAY 31 8:00 AM - 8:15 AM

Is Gait Variability Associated With Knee Osteoarthritis in Older Adults? A Case Control Study.

Joseph E. DeCaria1, Robert J. Petrella, FACSM1, Manuel Montero-Odasso2. 1Lawson Health Research Institute, London, ON, Canada. 2The University of Western Ontario, London, ON, Canada.

(No relationships reported)

PURPOSE: Knee osteoarthritis (OA) patients are at an elevated risk for falls. Increased spatio-temporal gait variability denotes gait instability, and is a valid and strong predictor of falls. However, the role of gait variability as a predictor of falls in knee OA is unknown. Our objective was to determine if gait variability is impaired in a sample of older knee OA patients compared with age matched healthy older adults.

METHODS: This case control study included 53 community dwelling older adults without a history of cognitive or neurological impairment. The gait characteristics of 30 older adults with mild-moderate knee OA were compared to those of 23 age-matched healthy older adults. Gait characteristics were determined at each participant’s self-selected velocity with a 10 metre electronic walkway (GAITRite). Gait variability was defined as the coefficient of variation (CoV) for stride time (StrTM) and stride length (StrL). Significant differences between groups (p<0.05) were determined using MANCOVA.

RESULTS: Mean age was 72.44 (±5.16) years old. Compared to controls, knee OA patients had a significantly greater BMI, fear of falling, and history of falls in the past year (all p<0.05). Meanwhile, the control group had a significantly greater proportion of females (82%) compared to the knee OA group (47%) (p=0.01). The knee OA group walked with a significantly slower velocity [111.14 (±24.44) cm/s] compared to the control group [125.10 (±16.29) cm/s] (p=0.02). The knee OA groups StrTM CoV was 3.24 (±0.97) % and StrL CoV was 4.22 (±1.94) %, while the control groups StrTM CoV was 2.09 (±0.71) % and StrL CoV was 2.50 (±1.45) %. When controlling for the significant covariate effects of gender and gait velocity, StrTM CoV was significantly greater in the knee OA group when compared to the control group [Mean difference (95% Confidence Interval)] [1.18 (1.72; 0.64) %] (p<0.001).

CONCLUSIONS: Gait variability is impaired in older adults with knee OA when compared with healthy controls. High gait variability may help to explain the high risk of falls in older people with knee OA. These results act as proof of principle for further investigation in a larger prospective trial assessing the impact of gait variability on falls prevalence in knee OA patients, and whether it is amenable to treatment.

643 MAY 31 8:15 AM - 8:30 AM

Lower Extremity Gait And Muscle Strength Asymmetry In Patients With Medial Compartment Knee Osteoarthritis

Talia R. Webber1, Kathryn Mills1, Mike B. Pohl2, Sang-Kyoon Park3, Reed Ferber1. 1University of Calgary, Calgary, AB, Canada. 2University of Kentucky, Lexington, KY. 3Korea National Sport University, Seoul, Korea, Democratic People’s Republic of. (Sponsor: Louis Osternig, FACSM)

(No relationships reported)

Asymmetrical gait patterns are a common feature of knee osteoarthritis (KOA) that may lead to increased loading and KOA disease progression. It is hypothesized that the degree of gait asymmetry is influenced by muscular strength imbalances which may contribute to disease severity.

PURPOSE: To investigate between-limb ankle, knee, and hip kinematic and hip and knee muscle strength asymmetry in patients with medial compartment KOA and healthy controls.

METHODS: Thirty-eight individuals with mild medial compartment KOA (27 females, 11 males; age: 53.67±8.27 yrs) and 30 healthy controls (21 females, 9 males; age: 53.23±12.02 yrs) participated. Maximum isometric force output of the hip abductors, knee extensors and hip external rotators were measured bilaterally using a force dynamometer. Bilateral frontal plane range of motion of the pelvis, hips, knees and ankles as well as sagittal plane motion of the ankles and knees were measured using an 8-camera Vicon motion capture system while participants walked on a treadmill at 1.1m/s-1. Between-limb asymmetries were examined using paired two-tailed t-tests (p=0.05). Kinematic and strength asymmetries were then compared between groups using independent two-tailed t-tests (p=0.05).

RESULTS: For KOA, between-limb comparisons showed that the more involved limb exhibited significantly (p=0.01) less peak sagittal plane angle (-2.2° (-3.25 to -0.78) ES= 0.52) but significantly (p=0.05) greater peak sagittal ankle angle (1.08° (0.01 to 2.12) ES= 0.33) compared with the less-affected knee. Knee extensor (p=0.01) and hip external rotator (p=0.01) strength was also significantly less compared with the affected side (-3.59 N (-6.26 to -0.09) ES= 0.49 and -1.12 N (-1.93 to -0.29) ES= 0.44, respectively). Between-group comparisons showed KOA exhibited significantly greater strength asymmetries for the knee extensors (p=0.03) and hip external rotators (p=0.03) strength and a trend (p=0.06) towards greater asymmetry in peak knee sagittal plane (1.78° (-0.12 to 3.67)) angle compared with the control group.

CONCLUSION: Even at mild stages of the disease, individuals with medial compartment KOA exhibited gait kinematic and strength asymmetries compared with healthy controls. These data can be used to develop optimal rehabilitation programs or for gait retraining.

644 MAY 31 8:30 AM - 8:45 AM

Gait Changes with Valgus Unloader Braces in Patients with Knee Osteoarthritis

Cheryl L. Hubley-Kozey, Shawn M. Robbins, Derek J. Rutherford, William J. Stanish. Dalhousie University, Halifax, NS, Canada.

(No relationships reported)

The mechanism by which valgus unloader braces (VUB) improve pain and function in patients with medial compartment knee osteoarthritis (OA) is unclear. VUB are designed to decrease joint load, but mixed results have been presented with respect to changes in knee joint loading.

PURPOSE: To examine the effect of six months of VUB wear on dynamic changes in 3 dimensional joint mechanics and muscle activation patterns during walking in patients with moderate medial compartment knee OA.

METHODS: Participants with knee OA (n=28) wore a custom-fit VUB for 6 months and were tested at baseline and 6 months. Motion, force and surface electromyographic (EMG) data were collected using standard procedures as participants walked at their self-selected speed with and without VUB. Knee angles, moments and EMG waveforms for 7 muscles were calculated. Principal component analysis identified principal features (PC) from the gait waveforms. Each waveform was scored against the PC to yield a PC-score. A 2-way repeated measure ANOVA examined the effect of bracing and time on PC-scores (α=0.05).

RESULTS: No difference in walking speed (1.24m/s) was found among conditions. Significant brace effects were found for all 3 transverse and frontal plane angle, 2 sagittal plane angle, 1 medial gastrocnemius and 1 medial hamstring PC-scores. Significant time effects for a lateral gastrocnemius and an interaction for one knee flexion moment PC-score were found. Specifically transverse knee rotation angle PC1-score was higher for VUB (-5.40) compared to no brace (2.70) indicative of reduced knee rotation angular excursion with the VUB. Medial gastrocnemius PC2-score was lower with VUB (14.60) than with no brace (18.69) representing a phase shift with the VUB. Medial hamstring activation amplitude (PC1) was greater with VUB (104.54) than with no brace (99.37).

CONCLUSION: Knee adduction moment, a surrogate measure for medial compartment loading was not altered with VUB, but other mechanical and EMG features were. The knee rotation excursion and medial gastrocnemius alterations with VUB application are consistent with more severe knee OA gait. These findings together with increased medial hamstring activity support that dynamic neuromuscular mechanisms along with mechanical alterations are associated with VUB.

Supported by CIHR 200703ROP-175724

645 MAY 31 8:45 AM - 9:00 AM

Is There A Relationship Between Thigh Fat And Muscle Volume And Isometric Knee Strength And Physical Performance In Women With Knee Osteoarthritis?

Kristina M. Calder, Karen A. Beattie, Norma J. MacIntyre, Monica R. Maly. McMaster University, Hamilton, ON, Canada. (Sponsor: David Gabriel, FACSM)

(No relationships reported)

PURPOSE: To determine whether variance in thigh intermuscular fat (IMF) and quadriceps muscle (QM) volumes relate to variance in knee strength and physical performance in women with no radiographic evidence of osteoarthritis (NROA) and those with radiographic evidence of osteoarthritis (ROA) of the knee.

METHODS: Baseline data from women over the age of 50 enrolled in the Osteoarthritis Initiative (OAI) were randomly selected from a list of eligible candidates. The women were separated into NROA and ROA groups based on the Kellgren Lawrence (K-L) scoring system. K-L grade 0 or 1= the NROA group and K-L grade 2, 3 or 4 = ROA group. For each participant, T1-weighted axial magnetic resonance imaging scans comprised of 15 contiguous mid-thigh slices were segmented by a single segmenter using SliceOmatic 4.3 (TomoVision, Magog, QC, Canada). IMF and QM volumes (cm3) were yielded from analyzed images. Maximal isometric knee extensor strength (normalized to body weight, N/kg) was measured using a fixed force transducer. Physical performance represented the average time taken to stand from sitting 5 times (s). Hierarchical multiple regressions models were used to test if variance in knee strength and variance in physical performance would be explained by IMF and QM volumes in women with NROA and ROA.

RESULTS: The NROA group (N=52) was younger (60.7 ± 7.1 years), had lower BMI (26.2 ± 5.0 kg/m2), stronger knees (4.6 ± 1.3 N/kg) and performed the performace test faster (11.4 ± 3.4 s) than the ROA group (N=73; 64.6 ± 6.8 years; 29.3 ± 5.2 kg/m2 ;4.0 ± 1.0 N/kg; and 13.3 ± 4.4 s respectively; p<0.05). The NROA group (98.14 ± 31.98 cm3) had less IMF compared to the ROA group (117.29 ± 41.99 cm3, p<0.05). No group differences in QM volume was found (p<0.05). A model explaining 23.5% of the variance in knee strength included knee alignment, pain intensity and IMF volume. A model explaining 13.2% of the variance in physical performance included OA status and IMF volume.

CONCLUSIONS: IMF volume explained a small amount of variance in knee strength and performance among women with NROA and ROA of the knee. Surprisingly, QM volume was unrelated to knee function or physical performance. Possible suggestion for this finding may be that muscle volume does not reflect fatty infiltrates with muscle or muscle mechanics known to affect force output from muscles.

646 MAY 31 9:00 AM - 9:15 AM

Changes in Quadriceps Activation Predicts Changes in Strength after Exercise in Patients with Knee Osteoarthritis

Brian G. Pietrosimone1, Susan Saliba2. 1University of Toledo, Toledo, OH. 2University of Virginia, Toledo, OH.

(No relationships reported)

Lower extremity neuromuscular alterations are common in those with tibiofemoral osteoarthritis. Voluntary quadriceps activation and muscle weakness predict increased disability in this population. It has been suggested that specifically improving quadriceps activation would optimize gains in muscle strength. Unfortunately, the relationship between changes in volitional activation and muscle strength has not been determined.

PURPOSE: To determine if changes in voluntary quadriceps activation could predict changes in quadriceps strength following a 4-week therapeutic exercise regimen.

METHODS: Thirty participants (14 males, 16 females, 58 ± 11.8 years, 172.2 ± 9.2 cm, 87.1 ± 18.5 kg) with tibiofemoral osteoarthritis finished the four-week supervised therapeutic exercise protocol which focused on improving quadriceps function. Demographics, quadriceps strength measured via maximal voluntary isometric contractions (MVIC), and voluntary quadriceps activation using the burst superimposition technique were evaluated prior to the intervention. Following the therapeutic exercise program, quadriceps strength and voluntary activation were assessed. Simple correlations were performed to determine covariates in a multiple regression equation to evaluate if changes in voluntary quadriceps activation could predict changes in quadriceps strength.

RESULTS: There was a significant moderate simple correlation between participant height and change in MVIC (r = -0.44, P= 0.01). Both height and changes in voluntary quadriceps activation significantly predicted changes in MVIC (R2= 0.66, P < 0.001). After controlling for patient height, a change in voluntary quadriceps activation produced a significant improvement in the prediction of a change in MVIC (ΔR2=0.47, P <0.001).

CONCLUSIONS: Changes in voluntary quadriceps activation predicted 47% of variance in the change in quadriceps strength. These results suggest that interventions aimed at manipulating quadriceps activation may be helpful for improving quadriceps strength in patients with tibiofemoral osteoarthritis. ACKNOWLEDGEMENTS: The authors would like to thank the American Physical Therapy Association, Orthopaedics Section and National Athletic Trainers Association Research and Education Foundation for funding this study.

647 MAY 31 9:15 AM - 9:30 AM

Gait Biomechanics and Muscular Strength in Patients with Patellofemoral Osteoarthritis

Michael B. Pohl1, J Preston Wiley2, Chirag Patel2, Reed Ferber2. 1University of Kentucky, Lexington, KY. 2University of Calgary, Calgary, AB, Canada. (Sponsor: Robert Shapiro, FACSM)

(No relationships reported)

A significant number of patients with patellofemoral osteoarthritis (PFOA) have described a history of patellofemoral pain syndrome (PFPS). This leads to speculation that the underpinning mechanical causes of PFPS and PFOA may be similar. Deficiencies in hip abduction and external rotation strength have been reported in PFPS patients. In addition, excessive hip adduction and internal rotation during gait are also evident in those with PFPS. However, no study has explored whether similar alterations in hip strength or gait biomechanics exist in PFOA patients.

PURPOSE: To compare gait biomechanics and hip muscular strength between PFOA patients and a healthy control group. It was hypothesised that compared to controls, PFOA patients would demonstrate greater hip adduction (ADDang), hip internal rotation (IRang) and contra-lateral pelvic drop (PDang) during walking together with reduced hip abduction (ABDstr) and external rotation (ERstr) muscular strength.

METHODS: Fifteen patients with symptomatic, radiographic PFOA and 15 controls participated. Lower extremity biomechanical data were collected during treadmill walking. Biomechanical variables of interest included the peak values of PDang, ADDang and IRang during the stance phase. For muscular strength, ABDstr and ERstr were assessed using maximal voluntary isometric contractions against a force dynamometer. Strength values were expressed as a percentage of body weight. Between-group comparisons for all variables were conducted using independent t-tests.

RESULTS: The PFOA group demonstrated significantly lower ABDstr compared to controls (PFOA: 28.1±10.6, CON: 37.4±8.7 %BW, p=0.01). There were no statistical differences between the PFOA and control groups for ADDang (PFOA: 9.0±2.5°, CON: 8.6±3.4°, p=0.74), IRang (PFOA: 6.9±5.1°, CON: 6.2±6.6°, p=0.74), PDang (PFOA: 3.0±1.3°, CON: 2.5±8.7°, p=0.42) or ERstr (PFOA: 12.3±3.2, CON: 13.7±5.1 %BW, p=0.42).

CONCLUSION: Patients with PFOA exhibited weaker hip abductor muscle strength compared to their healthy counterparts. However, the PFOA group did not demonstrate any alterations in pelvis or hip biomechanics during gait. These preliminary data suggests that weaker hip abductor strength does not necessarily result in biomechanical alterations during gait.

648 MAY 31 9:30 AM - 9:45 AM

Post-Traumatic Ankle Osteoarthritis Influences Stair Ascent Kinetics

Erik A. Wikstrom1, Tricia J. Hubbard-Turner1, Robert B. Anderson2. 1University of North Carolina at Charlotte, Charlotte, NC. 2OrthoCarolina Foot & Ankle Institute, Charlotte, NC.

(No relationships reported)

Post-traumatic ankle osteoarthritis (PTAO) is a condition characterized by pain and disability and is often the result of a ligamentous injury or fracture to the ankle joint complex. Research has consistently identified significant increases in clinical disablement but only recently begun to systematically quantify sensorimotor dysfunction in this population. To date, those with PTAO have been shown to have a number of sensorimotor impairments. However, no investigation has quantified how PTAO affects sensorimotor function during activities that are not completed over level ground.

PURPOSE: To determine if PTAO influences the kinetic patterns of stair ascent relative to age matched controls.

METHODS: Nine subjects with unilateral PTAO and eight age- matched controls volunteered to participate. Participants completed a total of 5 ascents up a custom built stair case that housed an embedded force plate within the second step. All trials were conducted so that the PTAO subjects struck the force plate with their involved limb while the controls subjects struck the force plate with the matched limb. The primary outcome measures included the peak and normalized, relative to body weight, vertical ground reaction force during weight acceptance (F1) and terminal stance (F2) as well as the unloading force during midstance (Fmin). Both the raw and normalized peak forces, relative to body weight, were submitted for further analysis.

RESULTS: Demographic characteristics did not differ between the groups. Analysis of the raw force data revealed significantly higher F1 (PTOA: 707±105N, Control: 518±114N) and F2 (PTOA: 718±81N, Control: 599±111N) peak forces (p<0.03) in the PTOA group. When normalized to body weight, those with PTAO still had significantly higher values (p<0.03) at F1 (PTOA: 1.03±0.28%, Control: 0.65±0.28%) but only a statistical trend at F2 (p=0.07) (PTOA: 1.05±0.27%, Control: 0.76±0.29%). No differences were seen at Fmin (p>0.05).

CONCLUSION: The results suggest that the stair ascent kinetic patterns used by those with PTAO are due to a reduced ability to attenuate weight acceptance. These findings are consistent with previously identified sensorimotor impairments during level ground ambulation in this population.

Supported by a grant from the American Orthopedic Foot and Ankle Society.

649 MAY 31 9:45 AM - 10:00 AM

Differences in Walking Mechanics between End-stage Ankle and Hip Osteoarthritis

Robin M. Queen, Robert J. Butler, Mary E. Russell, Michael P. Bolognesi, James A. Nunley. Duke University, Durham, NC. (Sponsor: Donald T. Kirkendall, FACSM)

(No relationships reported)

Walking dysfunction is common in end stage hip (H-OA) and ankle (A-OA) osteoarthritis, but specific differences between these groups are not well understood.

PURPOSE: To compare the differences in gait mechanics between patients with end-stage ankle and hip OA with healthy control subjects.

METHODS: Seventy-five subjects were included in this study: 30 subjects with unilateral end-stage A-OA, 30 age-matched subjects with end-stage H-OA and 15 healthy controls (C). Spatiotemporal and sagittal plane lower extremity kinematics and vertical ground reaction forces (vGRF) were collected during 7 self-selected speed walking trials.

RESULTS: The C group was significantly younger, weighed less, and had increased knee flexion compared with A-OA and H-OA (P<0.009). Walking speed A-OA (0.84 ± 0.24 m/s) < H-OA (1.06 ± 0.22 m/s) < C (1.38 ± 0.22 m/s), step and stride length differed between all groups (P<0.001). Ankle plantarflexion was decreased while step time was increased in A-OA compared with H-OA and C (P<0.006). Hip extension and hip range of motion (ROM) were smallest for H-OA followed by A-OA and C (P<0.001). Finally, H-OA demonstrated decreased knee extension, and vGRF as well as increased ankle dorsiflexion, and hip flexion (P = 0.043) when compared to A-OA and C. Knee ROM was greatest in the H-OA (36.26 ± 6.96 Deg) followed by the C (29.06 ± 4.28 Deg) and finally the A-OA group (27.11 ± 5.61 Deg).

CONCLUSIONS: The location of OA dictates the nature of compensatory strategies during walking. The A-OA patients demonstrate the greatest limitations in global walking mechanics (speed, stride and step length), while the H-OA subjects compensated at the ankle and knee to improve walking speed. Our results indicate that the presence of ankle OA had the greatest impact on global walking mechanics.

C-20 Free Communication/Slide - Physical Activity and Diet: Changes in Weight and Body Fat

MAY 31, 2012 8:00 AM - 9:30 AM

ROOM: 2007

650 Chair: John M. Jakicic, FACSM. University of Pittsburgh, Pittsburgh, PA.

(No relationships reported)

651 MAY 31 8:00 AM - 8:15 AM

Men and Women Show Similar Reductions in Fat Mass to 12 Weeks of Supervised Exercise

Phillipa Caudwell1, Catherine Gibbons1, Mark Hopkins1, Neil King2, Erik Naslund3, Graham Finlayson1, John Blundell1. 1University of Leeds, Leeds, United Kingdom. 2Queensland University of Technology, Brisbane, Australia. 3Karolinska Institute, Stockholm, Sweden.

(No relationships reported)

Exercise alone is often reported to produce little or moderate weight loss. It is also reported that women experience less exercise-induced weight and fat loss compared with men. Both of these outcomes could be explained by compliance, energy expenditure (EE), or compensatory responses in energy intake (EI). Differences in compliance and energy expenditure can be overcome by supervising and fixing the exercise intervention.

PURPOSE: To examine the impact of 12 weeks supervised and fixed EE aerobic exercise training on body composition, appetite and food intake in men and women.

METHODS: 107 overweight and obese men (n=35) and women (n=72) with a mean BMI= 31.4±4.2kg/m2 and age= 40.9±9.2years, completed a 12 week supervised exercise program designed to increase gross EE by 2500kcal/wk. Portfolios of anthropometric, physiological and behavioural variables were measured at weeks 0 and 12. EI was measured objectively using a test meal design conducted in the laboratory.

RESULTS: 12 weeks of exercise induced significant reductions in body mass (-3.03±3.4 and -2.28±3.1kg), fat mass (-3.14±3.7 and -3.01±3.0kg) and % body fat (-2.45±3.3 and -2.45±2.2%) in men and women respectively (all p<0.0001). There were no significant differences in the changes in body mass and fat mass between the genders (p>0.05).There was a significant increase in fasting hunger after 12 weeks of exercise (11.0±21.1 and 14.0±22.9mm, p<0.0001) but no effect of gender (p>0.05). However, there was no significant change in total daily EI (+47.6±578.5, and -31.5±459.3, p>0.05) in men and women respectively.

CONCLUSIONS: Men and women responded to the exercise intervention in a similar manner and achieved the same fat loss when the exercise was supervised and exercise energy expenditure was equivalent. Compensatory mediating processes in response to a mandatory exercise regime were similar in men and women.

Supported by Biotechnology and Biological Sciences Research Council (BB51/B/05079 and BB/G005524/1).

652 MAY 31 8:15 AM - 8:30 AM

Effect Of A Low-carbohydrate Versus A Low-fat Weight Loss Program On Body Composition

Kerry J. Stewart, FACSM, Pamela Ouyang, Harry A. Silber, Sammy Zakaria, Dipan Desai, Edward P. Shapiro, Devon A. Dobrosielski. Johns Hopkins, Baltimore, MD.

(No relationships reported)

PURPOSE: Successful weight loss programs reduce fat mass yet there is often concomitant loss of lean and bone mass. We compared the effect on body composition of 6 months of a low-carbohydrate (LC) versus a low-fat (LF) diet. All subjects also followed a supervised exercise program.

METHODS: Overweight or obese but otherwise healthy subjects, aged 30-65 years, were randomly assigned to an isocaloric LC or LF diet. Exercise was scheduled 3 times/week following ACSM guidelines. We assessed body weight, BMI, dual energy X-ray absorptiometry derived body composition, peak oxygen uptake, isokinetic muscle strength, and energy intake and expenditure.

RESULTS: Sixty subjects (LC, n=31,74% women; LF, n=29, 72% women) completed the study. At baseline, the groups were similar in age and body composition. Combined group values are: age, 50.0±8.7 years; weight, 97.7±14.9 kg; BMI, 34.2±3.8 kg/m2; total fat mass, 42.1±9.9 kg, lean mass, 51.9±10.2 kg, bone mass, 3.2± 0.6 kg, and trunk fat, 22.5±5.3 kg. At 6 months, aerobic and strength fitness increased similarly in both groups with gains in peak oxygen uptake of 23%, and peak torque for knee extension of 19% and flexion of 20%, all p<0.01. Both groups had similar daily caloric intake (overall 1606±421.5 kcal) and daily energy expenditure (overall 34.0±1.5 kcal/kg) at 6 months. The LC versus the LF group had greater reductions in weight, -13.1±5.0 versus -8.2±4.7 kg; BMI, -4.7±2.0 versus -2.9±1.7 8 kg/m2; total fat mass, -11.1±4.5 versus -6.5±4.5 kg; and trunk fat, -6.5±3.2 versus -3.8±3.3 kg, all p<0.01. Both groups had a modest and similar loss of lean mass (overall -1.5±2.7 kg, p<0.001). Bone mass did not change in either group, p=0.51.

CONCLUSIONS: The LC program resulted in a substantially greater loss of body weight than the LF program, explained by a greater loss of general and central fat without greater loss of lean and no loss of bone mass. Both groups had similar daily caloric intake and energy expenditure, increased aerobic fitness, and despite a modest loss of lean mass, increased muscle strength. Thus, group differences in body composition can be attributed to the macronutrient content of the diet. A LC diet plus exercise program appears to be more effective for weight loss and improving body composition compared with a LF approach.

Supported by NIH Grants RO1 HL092280 and UL1 RR 025005.

653 MAY 31 8:30 AM - 8:45 AM

Dose of Objectively Measured Physical Activity Associated with Successful 18-Month Weight Loss Maintenance

John M. Jakicic, FACSM1, Kelliann K. Davis1, Kristen Polzien2, Karen Erickson2, Amy D. Rickman1, Deborah F. Tate2. 1University of Pittsburgh, Pittsburgh, PA. 2University of North Carolina - Chapel Hill, Chapel Hill, NC.

( J.M. Jakicic: Contracted Research - Including Principle Investigator; BodyMedia, Inc..)

It is recommended to participate in 250 to 300 min/wk of moderate-to-vigorous intensity physical activity (MVPA) to improve long-term weight loss (ACSM, 2009), yet few studies have quantified physical activity using objective methods. Moreover, little is known about the influence of lower intensity physical activity (LPA) on weight loss maintenance.

PURPOSE: To examine the association of objectively measured MVPA and LPA on long-term maintenance in overweight and obese adults.

METHODS: 227 adults (BMI=32.6±3.5 kg/m2; age=43.0±9.1 years) with complete data who participated in an 18 month behavioral weight loss intervention, and were instructed to reduce energy intake and to progressively increase MVPA. Weight and objectively measured physical activity (SenseWear Pro Armband) were assessed at 0, 6, and 18 months. MVPA was defined as bouts that were ≥10 minutes in duration and ≥3.0 METS. LPA was defined as minutes of activity between 1.5 to 2.9 METS. Analyses were performed with subjects grouped on weight loss at 6 and 18 months: <10% at 6 and 18 months (LOW-LOSS), ≥10% at 6 months and <10% at 18 months (NON-MAINTAIN), <10% at 6 months and ≥10% at 18 months (LATE-LOSS), and ≥10% at 6 and 18 months (MAINTAIN), with 38.3%, 17.6%, 8.4%, and 35.7% of subjects in these groups, respectively.

RESULTS: Percent weight loss was significantly lower at 18 months in LOW-LOSS (2.0±4.2%) and NON-MAINTAIN (6.6±2.3%) compared to LATE-LOSS (13.6±2.3%) and MAINTAIN (16.5±6.4%)(p<0.001). MVPA was significantly higher at 18-months in MAINTAIN (265±262 min/wk) compared to LATE-LOSS (165±171 min/wk), NON-MAINTAIN (130±161 min/wk), and LOW-LOSS (108±119 min/wk)(p<0.05). LPA at 18-months was significantly higher at 18-months in MAINTAIN (214±69 min/d) compared to NON-MAINTAIN (179±56 min/d), and LOW-LOSS (179±74 min/d)(p<0.05), but not significantly different than LATE-LOSS (188±83 min/d).

CONCLUSION: Maintenance of 10% weight loss is associated with relatively high levels of objectively assessed MVPA (265 min/wk) and greater LPA compared to those less successful at weight loss at 18 months. This supports the need for strategies to enhance the adoption and maintenance of this level of MVPA in combination with increased LPA to facilitate long-term weight loss maintenance.

Supported by the National Institutes of Health (HL008840)

654 MAY 31 8:45 AM - 9:00 AM

Racial Variation In Weight Loss And Physical Activity Among Women In A Behavioral Weight Loss Intervention

Kelli Davis1, Deborah Tate2, Kristen Polzien, FACSM3, Karen Erickson2, Amy Rickman1, John M. Jakicic, FACSM1. 1University of Pittsburgh, Pittsburgh, PA. 2University of North Carolina- Chapel Hill, Chapel Hill, NC. 3University of North Carolina-Chapel Hill, Chapel Hill, NC.

(No relationships reported)

BACKGROUND: African-American (AA) women tend to lose less weight in response to a behavioral intervention compared with White (W) women. Lower physical activity (PA) in response to the intervention has been implicated as a potential contributor to the lower weight loss in AA women. However, few studies have used objective monitoring of PA to support these claims.

PURPOSE: To examine weight loss and objective PA in W and AA women enrolled in a standard behavioral weight loss intervention (SBWI). METHODS Subjects (n=96; 41.4±8.9 yrs; BMI=32.9±3.4) participated in an 18-month SBWI that included weekly group sessions, decrease in energy intake to 1200-1500 kcal/d, and PA progression to 300 min/wk. Weight and PA were assessed at 0, 6, and 18 months. PA was assessed objectively using an armband that provided minute-by-minute data for a period of 7 days (SenseWear Pro ArmbandTM, Body Media, Inc.). Moderate-to-vigorous PA was defined as both min of activity ≥1 min in duration and ≥3 MET/min (MVPA), and as bouts of activity ≥10 min in duration and ≥3 MET/min (MVPA-B). Light PA (LPA) was defined as min of activity ≥1 min in duration and 1.5 to 2.9 MET/min.

RESULTS: Weight loss was significantly greater in W (-9.4±-5.4kg) compared with AA (-6.8±-4.4kg) (p<0.05) at 6 months, but not at 18 months (-8.9±-8.3 vs. -5.9±-6.4; p=.09). MVPA (min/wk) was significantly greater in W compared to AA at 6 (494.2±239.4 vs. 382.6±184.9) and 18 months (380.1±260.7 vs. 275.6±157.9) (p<0.05), respectively. There were no differences in MVPA-B between W and AA. LPA was not significantly different in W and AA at 6 mo, but was greater in W compared to AA at 18 mo (205.6±82.5 vs.166.2±58.5) (p<0.05).

CONCLUSIONS: AA women lost less weight (∼2.7 kg) than W women during the 18 month SBWI. Although there were no differences in bouts of moderate-to-vigorous PA that were ≥10min in duration (MVPA-B), white women performed more total minutes of MVPA and LPA per week than the AA women, which may explain some of the discrepancy in weight loss between these groups. Therefore, physical activity recommendations should continue to emphasize lifestyle activity as an important component of long-term weight loss success.

Support by the NIH (HL008840)

655 MAY 31 9:00 AM - 9:15 AM

Type 2 Diabetes Impairs Exercise Induced Reductions in Abdominal Fat

Devon A. Dobrosielski, Sameer Chaudhari, Gurusher Panjrath, Harry A. Silber, Sammy Zakaria, Dipan Desai, Edward P. Shapiro, Pamela Ouyang, Kerry J. Stewart, FACSM. Johns Hopkins School of Medicine, Baltimore, MD.

(No relationships reported)

PURPOSE: Exercise training has been shown to reduce total and regional fat but comparisons of this response in subjects with and without type 2 diabetes (T2DM) are lacking. We examined the effect of T2DM on body composition response to exercise training using data from two randomized clinical trials conducted by our group. Subjects in one of the trials had uncomplicated T2DM not requiring insulin; all subjects had mild hypertension.

METHODS: The trial of T2DM enrolled 140 subjects; the second trial enrolled 115 subjects. Subjects, aged 40 to 75 years, were randomized to the same supervised exercise 3 times per week (EX) following ACSM guidelines, or to a usual care (UC) control group. Key outcomes were measured in the same manner in both trials and included body weight, total body fat % by dual-energy X-ray absorptiometry, abdominal fat by magnetic resonance imaging and peak oxygen uptake (VO2) on a treadmill.

RESULTS: There were 217 subjects who completed the trials (n= 101 EX, n=50 had T2DM; 116 UC, n= 63 had T2DM). At baseline, the key outcomes did not differ between EX vs. UC regardless of diabetes status. The following baseline differences were found for T2DM vs. non-T2DM: age: 56.4 ± 6.1 yrs vs. 63.7 ± 5.6 yrs, weight: 98.3 ± 15.8 kg vs. 83.6 ± 16.8 kg; total abdominal fat: 588.8 ± 153.4 vs. 439.7 ± 139.3 cm2, subcutaneous fat: 402.3 ± 132.3 vs. 296.0 ± 116.2 cm2; and peak VO2: 22.0 ± 5.5 ml/kg/min vs. 24.2 ± 5.1 ml/kg/min, (p<0.01 for all). EX improved peak VO2 (3.6 ± 2.9 ml/kg/min), and reduced total body fat (2.5 ± 2.5 %) and body weight (2.2 ± 3.9 kg), (p<0.01 for all). Using a general linear model with adjustment for baseline values, age, and fitness, exercise training reduced total abdominal fat, -52.5 ± 49.2 cm2; subcutaneous fat, -25.6 ± 32.5 cm2; and visceral fat, -26.7 ± 30.8 cm2, (p<0.01 for all), in those without T2DM, whereas outcomes did not change in subjects with T2DM.

CONCLUSION: Though subjects with T2DM attained an exercise training effect as evidenced by increased fitness and reduced total body fat, the key finding was a lack of reduction in abdominal obesity in T2DM. Those without T2DM attained this important benefit of exercise. Whether this failure to reduce abdominal fat is due to metabolic abnormalities or use of medications for diabetes management is yet to be determined.

656 MAY 31 9:15 AM - 9:30 AM

Childhood Percent Body Fat Is Associated With Physical Inactivity, Not Energy, Fat Or Sugar Intake.

Richard D. Telford, FACSM1, Ross B. Cunningham2, Malcolm Riley3, Rohan M. Telford4, Walter P. Abhayaratna1. 1The Canberra Hospital, Canberra, Australia. 2Australian National University, Canberra, Australia. 3Commonwealth Scientific and Industrial Research Organization, Melbourne, Australia. 4University of Canberra, Canberra, Australia.

(No relationships reported)

Whilst energy intake and output are the fundamental effectors in the accumulation of body fat, their relative influence in pre-adolescent children remains a subject of debate.

PURPOSE: To investigate the relationships of physical activity (PA), total daily energy and macronutrient intake with the percentage of body fat (%BF) in healthy, free-living pre-adolescent Australian children.

METHODS: Participants were 734 non-selected Australian pre-adolescent boys and girls from suburbs of socioeconomic status similar to the Australian average. Measurements were made on three occasions at approximately 8, 10, and 12 years of age. These included: height, weight, %BF (dual-energy X-ray absorptiometry); average daily PA (7-day pedometers), average daily moderate-vigorous physical activity (MVPA, 7 day accelerometers, final year only); total daily energy, fat, carbohydrate and sugar intake (parent/teacher assisted one and two-day records) and pubertal development (Tanner stage).

RESULTS: Negative between-child relationships emerged between %BF and PA in boys and girls (both p<0.001) and also between %BF and MVPA (p<0.01 and <0.001 for girls and boys respectively). Whilst %BF was associated with total energy (p=0.05), carbohydrate (p=0.01) and sugar intake (p=0.06) in boys, each of these relationships was also negative, with no relationships being evident in the girls. There were no statistically significant within-child relationships. Separate analysis of the 8 year-olds, and of all children divided into high and low %BF categories, revealed similar relationships, suggesting that under-reporting of dietary information in children with higher %BF was not an influential factor.

CONCLUSION: Pre-adolescent children with higher %BF were less physically active, but did not consume more energy, sugar or fat than their leaner counterparts; evidence suggested that boys with higher %BF actually consumed less energy, carbohydrate and sugar. Whilst energy intake and food composition are both instrumental in the development of %BF, our data suggest that increasing physical activity should form the primary focus of any strategy designed to reduce obesity in Australian children of average socioeconomic status.

F-17 Free Communication/Slide - Built Environment

JUNE 1, 2012 1:00 PM - 3:00 PM

ROOM: 2005

657 Chair: John R. Sirard. University of Virginia, Charlottesville, VA.

(No relationships reported)

658 June 1 1:00 PM - 1:15 PM

Access To And Use Of School Facilities For Physical Activity Among Adults

Carmen D. Harris, Dianna D. Carroll, Janet E. Fulton, FACSM. Centers for Disease Control and Prevention, Atlanta, GA.

(No relationships reported)

BACKGROUND: Having access to places to engage in physical activity may improve physical activity levels among U.S. adults. Little is known about adult’s access to local school facilities and their use of them.

PURPOSE: Describe the proportion of adults who report having access to facilities on local school property for the purpose of group or individual physical activity. Of those who report access, determine the proportion that use the facilities for physical activity.

METHODS: Responses from 3,753 adults to a consumer mail panel survey, HealthStyles 2010, were used to determine access and use of school facilities by adults. Access was defined as a “yes” response to having access to any of the following local elementary, middle, or high school facilities outside of school hours: outdoor track, general use field, indoor gymnasium, outdoor tennis court, baseball/softball field, soccer/football field, indoor weight room/fitness center, or outdoor volleyball/basketball court. Use was defined as a “yes” response to the question “In a usual week, do you use any of your local school physical activity or athletic facilities for physical activity?”Prevalence and 95% confidence intervals (CI) were calculated using SUDAAN 9.2 and weighted to the 2000 U.S. Census population data.

RESULTS: Overall, 28.2% (CI: 26.0, 30.6) reported having access to a local school facility for physical activity. Outdoor tracks (20.1%), baseball or softball fields (13.4%), and outdoor tennis courts (12.8%) were the facilities reported most frequently, while indoor gyms (4.7%) or indoor weight room/fitness centers (6.6%) were identified by fewer adults. Among those who reported having access, 19.9% (CI: 15.5, 25.1) reported using local school facilities for physical activity.

CONCLUSION: About 3 out of 10 adults reported having access to local school facilities for physical activity. Access to outdoor facilities was reported more often than indoor facilities. Increasing access to facilities through approaches such as joint-use agreements to share school facilities and by providing informational outreach on the availability of facilities may be considered as environmental or policy strategies to increase physical activity levels among U.S. adults.

659 June 1 1:15 PM - 1:30 PM

Use and Physical Activity in Southern Nevada Parks

Monica A. Lounsbery1, Thomas L. McKenzie, FACSM2, Brian Funk1, Kathryn A. Holt1. 1University of Nevada, Las Vegas, Las Vegas, NV. 2San Diego State University, San Diego, CA.

(No relationships reported)

PURPOSE: Parks are important community resources for supporting physical activity (PA), especially for low-income individuals. Our purpose was to assess park use and PA in low socio-economic areas of Las Vegas Nevada.

METHODS: Trained observers used the System for Observing Physical Activity and Recreation in Communities (SOPARC) to assess the use and PA of 212 activity areas in 6 parks 4 times per day for 12 days each over 3 temperature seasons. Focus group meetings, residential surveys, and intercept interviews with adults were also conducted to gain insight into interests, park perceptions, and barriers to use.

RESULTS: We observed 33,362 park users, including children (26%), adolescents (21%), adults (47%), and seniors (6%). For all age groups, more males (61%) than females were observed. Overall, park users were observed being sedentary (i.e., lying down, sitting, standing) 51% of the time, compared to walking and vigorous activity, 32% and 17% respectively. Males were more likely to engage in vigorous PA (19 vs. 13%). During focus groups, adults identified parks as important locations for PA and for developing a sense of community. The greatest barrier to park use was lack of time, and the preferred activity was walking.

CONCLUSIONS: Females and seniors were relatively underserved. Women emphasized time challenges as primary barriers, while seniors felt unsafe being in the park with much younger age groups. It appears that strategies for increasing PA in parks for busy adults, especially women, should focus on creating time efficiencies. For those coming to parks to supervise (children or dogs) or be spectators, some time inefficiencies could be addressed by redesigning park facilities to include walking paths around the perimeters of park spaces. Strategic programming that simultaneously scheduled programs for children and parents in adjacent park spaces may also help address time barriers. Strategies for increasing park use and PA among seniors should focus offering low cost, age-specific program opportunities.

Supported in part by a grant from the Lincy Institute.

660 June 1 1:30 PM - 1:45 PM

Perceptions Of The Built Environment In Two Micropolitan Communities Of Different Population Densities

Charilaos Papadopoulos, Tiffany R. Quilter, Vincent M. Nethery, Michael Riggs. Central Washington University, Ellensburg, WA. (Sponsor: James A. Doyle, FACSM)

(No relationships reported)

Land use patterns have been studied in urban, and some rural communities throughout the United States. It has been shown that neighborhood characteristics like street connectivity, population density, and land use mix are associated with physical activity among adults.

PURPOSE: The study examines the difference in perceptions of the built environment and objectively measured physical activity levels in two micropolitan (i.e., small town) communities that are dissimilar in population density.

METHODS: Participants (n=39) from Ellensburg, WA (high density) and Moses Lake (low density) completed surveys and wore an accelerometer for up to 7 days. The Neighborhood Environmental Walkability Scale-Abbreviated survey was used to assess perceived neighborhood characteristics. Independent t tests examined differences in activity levels and neighborhood perceptions between the two micropolitan communities. Pearson’s correlations examined relationships between physical activity and characteristics of the perceived built environment within the geographic subgroups.

RESULTS: There were no significant differences in objectively measured physical activity between the two micropolitan communities. Few differences in perceived neighborhood environment existed. The low density community residents perceived less safety from traffic (p = 0.02) but higher infrastructure and safety for walking (p = 0.03) relative to high density residents. For the high density community, there was a significant correlation between moderate physical activity and personal safety (r = 0.53; p = 0.03). There were no significant correlations between any environmental characteristics and physical activity for the low density community residents.

CONCLUSIONS: Adults residing in two different density micropolitan communities did not differ in physical activity. Although the low density community residents perceived lower perception of safety, more sidewalks may create opportunities in getting sufficient physical activity in low density micropolitan areas.

661 June 1 1:45 PM - 2:00 PM

Neighborhood Walkability and Patterns of Objectively Measured Physical Activity in a High-Density Asian City

Duncan J. Macfarlane, FACSM, Ka-Yiu Lee, Ester Cerin. The University of Hong Kong, Pokfulam, Hong Kong.

(No relationships reported)

Features of the built environment can be important determinants of our physical activity (PA) habits, with many Western studies showing residents of high-walkable

PURPOSE: We examined whether residents of high- and low-walkable neighborhoods in an ultra-dense Asian city (Hong Kong) would accrue different patterns of objectively measured PA.

METHODS: A total of 317 residents were recruited from 32 selected neighborhoods (balance of high/low walkability and high/low socio-economic status), aged 18-65 years. Each respondent was asked to wear an accelerometer for 7 days, with 277 providing analyzable data (4 days with >10 hr/d).

RESULTS: Residents from low-walkable neighborhoods recorded 20.5% more time in short 1-4 min bouts of all activity above the light threshold (62.2 v 51.6 min/d, ES=0.41), which was mainly due to greater activity within the low threshold (40.3 v 30.5 min/d, ES = 0.42). Few differences were seen in patterns of moderate or vigorous activity, although the low-walkable group showed 7.2% less sedentary time (492 v 530 min/d, ES=0.43) than their high-walkable counterparts.

CONCLUSIONS: High neighborhood walkability in Hong Kong was actually associated with lower amounts of short 1-4 min bouts of predominantly light activity, contrary to what might be inferred from Western studies. It is unclear if such high levels of walkability create a plateau effect or even an inverted-U shape in the walkability-PA relationship, with extreme walkability possibly requiring less activity to complete each short journey. Further studies, including the effects of confounders, are needed to confirm these findings.

Funding: Hong Kong Research Grants Council GRF (#747807H and #740907); National Cancer Institute grant R01CA127296.

662 June 1 2:00 PM - 2:15 PM

Invariance Tests of the Abbreviated Neighborhood Environment Walkability Scale

Heather A. Starnes1, Meghan H. McDonough1, Francine Laden2, Philip J. Troped1. 1Purdue University, West Lafayette, IN. 2Harvard School of Public Health and the Brigham and Women’s Hospital, Boston, MA.

(No relationships reported)

The factorial validity of perceived neighborhood environment measures across subgroups and settings has not been established.

PURPOSE: To test for factorial invariance of the Abbreviated Neighborhood Environment Walkability Scale (ANEWS) across subgroups based on individual and neighborhood characteristics.

METHODS: A sample of 2,920 Nurses’ Health Study participants (mean age=74 ± 7 yrs; 97% White) in California, Massachusetts, and Pennsylvania completed a mailed survey that included ANEWS items. ANEWS was designed to assess six dimensions of neighborhood walkability: land use mix access, street connectivity, infrastructure and safety for walking, aesthetics, traffic safety, and personal safety. To test invariance, the sample was divided into groups based on (a) level of walking limitations, (b) frequency of neighborhood walking, (c) primary neighborhood housing type, and (d) population density. In single-group confirmatory factor analyses, fit indices (RMSEA ≤ .08, CFI ≥ .90, TLI ≥ .90, and SRMR ≤ .08) and parameter estimates (e.g., factor loading ≥ |.30|) were used to evaluate whether baseline models in each group exhibited adequate fit. In multi-group confirmatory factor analyses these indices, along with Δ CFI ≤ .01 were used to evaluate increasingly restrictive hypotheses of configural, metric, scalar, and residual invariance.

RESULTS: Baseline models demonstrated acceptable fit across all groupings. All four levels of invariance were supported across groupings based on walking limitations, neighborhood walking, and type of housing ( CFI ≤ .01). Scalar invariance was not supported across neighborhood population density groups ( CFI = .04).

CONCLUSIONS: Evidence of all four levels of invariance provides strong support for the use of the ANEWS among adults with varying levels of walking limitations and neighborhood walking, and across different types of neighborhood housing. The finding of scalar non-invariance suggests that researchers should be cautious when comparing ANEWS scores between residents of low, medium and high population density neighborhoods. Further development and testing of perceived built environment measures across neighborhoods with varying levels of population density appears warranted.

663 June 1 2:15 PM - 2:30 PM

Facilitators And Barriers To Active Transportation In U.S. Adults, Healthstyles 2009

Dianna D. Carroll, Joan M. Dorn, Janet E. Fulton, FACSM. Centers for Disease Control and Prevention, Atlanta, GA.

(No relationships reported)

Walking and biking for transportation are ways to get the physical activity (PA) volume necessary to meet the 2008 Physical Activity Guidelines for Americans; however, active transportation (AT) prevalence is low. Understanding facilitators and barriers of AT in adults is key to designing interventions to improve AT participation.

PURPOSE: (1) Estimate the prevalence of U.S. adults who engage in AT; (2) Determine facilitators and barriers of AT and (3) Examine the association between AT and meeting the current aerobic guideline.

METHODS: We assessed self-reported AT participation in 4,052 adults using the 2009 HealthStyles survey. We examined the AT facilitators and barriers reported among those who do and do not engage in AT, respectively. Using multivariable logistic regression with adjustment for demographics and body mass index, we estimated adjusted odds ratios (AORs) for meeting the aerobic PA guideline.

RESULTS: 17% of U.S. adults reported engaging in AT weekly. The top 3 reasons for AT were to get exercise [80.0% (95% CI: 74.5, 84.6)], enjoyment of AT [60.1% (54.7, 64.3)], and destinations are nearby [50.6% (45.4, 55.8)]. The top barrier among adults reporting no AT was destinations are too far away (Table). Compared with adults who do not engage in AT, those who do were over twice as likely to meet the aerobic guideline [AOR: 2.64 (95% CI: 2.06, 3.37)].

CONCLUSION: Nearly 2 out of 10 adults reported engaging in AT in a usual week. Perceived destination distance is a predominant reason why adults engage in AT or not. Our findings support AT as a way to help achieve the aerobic guideline. Future research should explore ways to combine AT with other transportation modes to facilitate AT when longer destination distance is a factor.

664 June 1 2:30 PM - 2:45 PM

Table: Prevalence an...
Table: Prevalence an...
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Association Of The Built Environment With Physical Activity And Adiposity In Rural And Urban Children

Justin B. Moore, FACSM1, Jason Brinkley2, Thomas W. Crawford3, Kelly R. Evenson4, Ross C. Brownson5. 1Arnold School of Public Health, University of South Carolina, Columbia, SC. 2College of Allied Health Sciences, East Carolina University, Greenville, NC. 3Harriot College of Arts & Sciences, East Carolina University, Greenville, NC. 4Gillings School of Global Public Health,University of North Carolina – Chapel Hill, Chapel Hill, NC. 5George Warren Brown School of Social Work, Division of Public Health Sciences and Alvin J. Siteman Cancer Center, School of Medicine, Washington University in St. Louis, St. Louis, MO.

(No relationships reported)

PURPOSE: To determine if differences exist for body mass index (BMI) and moderate to vigorous physical activity (MVPA) between rural and urban middle-school youth, and to determine if environmental supports for physical activity are differentially correlated with MVPA and BMI across settings.

METHODS: Cross-sectional analyses of 445 middle school children from a rural county and an adjacent urbanized area were performed. Data were collected on perceived and objective barriers/supports for physical activity, cardiovascular fitness, BMI, and MVPA via accelerometry. Multivariable linear models were used to estimate associations between BMI/MVPA and self-reported barriers/supports for physical activity and objectively measured neighborhood spatial variables.

RESULTS: After controlling for covariates, no differences between urban and rural children’s BMI were observed. Mean MVPA was significantly higher for rural children (14.0 minutes/day) compared to urban children (17.7 minutes/day), after adjusting for race, sex, and BMI. In the MVPA model, a modest amount variance was explained (R-square = 0.33), with sex and BMI contributing the greatest proportion to the model and objective distance to mixed-use destinations and perceived safety as significant predictors. Perceived environmental correlates for MVPA were similar associated in rural and urban children. Differences were observed for associations with BMI between locations, with the “Physical barriers to reach facilities” item showed a stronger association with urban children’s BMIs versus rural children. However, the item “Free recreation facilities in neighborhood” was more strongly associated with lower BMI in rural children compared with urban children. The multivariable model for BMI explained a small amount of variance (R-square = 0.12) with MVPA and age the largest contributors, although perceived crime was a significant predictor.

CONCLUSIONS: While no differences were observed in correlates for MVPA between rural and urban children in the present sample, differences were observed for BMI across the settings suggesting that rurality should be considered when identifying targets for interventions to prevent adiposity in youth. Future research should be conducted to further elucidate these differences in rural and urban youth.

665 June 1 2:45 PM - 3:00 PM

Contribution Of The CiclovÍA And Cicloruta Programs In BogotÁ-colombia To Meeting The Physical Activity Recommendations

Ana M. Cardona1, Andrea Torres2, Carolina Donado1, Christine Stauber3, Olga Lucia Sarmiento1. 1Universidad de los Andes, Bogotá, Colombia. 2Centers for Disease Control and Prevention (CDC), Atlanta, GA. 3Georgia State University, Atlanta, GA.

(No relationships reported)

Regular physical activity (PA) has shown to be a protective factor for chronic diseases. In Bogotá, there are two programs with strong potential to increase PA levels.

The Ciclovía (CV) is a community-based program in which streets are temporarily closed to motorized vehicles to exclusively allow access to pedestrians, cyclist, rollerbladers, and others, every Sunday and holiday of the year. The participation of the program is around 1,000,000 people per Sunday along the 60-mile circuit, which also offers a variety of complementary physical activities.

The Cicloruta (CR) System is the most extensive bicycle path network in Latin America with 186.4 miles of cycling paths, connected with public transportation, providing access to several destinations in the city.

Despite the relevance of the programs, there wasn’t a designed methodology to estimate the contribution to meeting PA recommendations (PAR).

PURPOSE: To estimate the contribution of the CV and the CR towards meeting PAR as a result of leisure time PA (LTPA) and transportation PA (TPA) in adults who attend to the programs.

METHODS: Two intercept surveys were performed in 1000 adults 18 years old and over who were using the CV and the CR programs. The long version of the International Physical Activity Questionnaire (IPAQ) was used to assess LTPA and TPA. Individuals were classified as meeting the PAR (at least 150 minutes of moderate PA) and not meeting the PAR (<150 minutes of moderate PA). The statistical analysis was carried out using SAS 9.2 software. The associations were measures using a chi square test.

RESULTS: Of 1000 people who attend to the CV Program, 59.5% meet PAR as a result of LTPA and 17.4% as a result of TPA. Of 1000 people who use the CR, 40.3% meet PAR as a result of LTPA and 70.5% as a result of TPA. Meeting PAR in leisure time was higher in people who attend to CV compared to CR (p<.0001). In people who attend to CR, meeting PAR as a result of transportation was higher than in CV (p<.0001) and those who met TPA recommendations were more likely to participate in CV in the last 12 months (OR 1.6; 95% CI 1.1-2.2).

CONCLUSIONS: CV and CR programs have shown to be important strategies in the promotion of meeting PAR as a result of LTPA and TPA, respectively, in the population of Bogotá-Colombia.

F-18 Free Communication/Slide - Cardiovascular

JUNE 1, 2012 1:00 PM - 2:30 PM

ROOM: 2020

666 Chair: Leonard A. Kaminsky, FACSM. Ball State University, Muncie, IN.

(No relationships reported)

667 June 1 1:00 PM - 1:15 PM

Effect Of Simulated Diving Trips On Pulmonary Artery Pressure In Healthy Men

Jochen Hansel, Kay Tetzlaff, Detlef Axmann, Andreas Niess, Christof Burgstahler. University clinic of tuebingen, Tuebingen, Germany.

(No relationships reported)

PURPOSE: Scuba diving may determine acute changes of cardiovascular function. Enviromental stresses such as immersion, cold and venous gas microbubbles have been shown substantially to contribute to right ventricular overload. We investigated cardiac function after simulated dry chamber dives.

METHODS: 17 male divers (mean age 32 years, standard deviation (SD) 7 years, mean body mass index 26 kgm-2 (SD 3 kgm-2) participated in the study. Heart disease was ruled out by ECG, stress-ECG and transthoracic echocardiography in all subjects. Echocardiographic assessment of pulmonary artery pressure (peak gradient at pulmonary and tricuspid valve), acceleration time (AT), ejection time (ET) and the ratio AT/ET as an estimate of pulmonary artery pressure was performed directly prior to and directly after as well as 20 and 80 minutes after a simulated diving trip (maximal pressure 600 kPa, duration 60 min).

RESULTS: AT/ET statistically significant decreased from 0.40 (SD 0.04) to 0.34 (SD 0.03) directly after the dive (p= < 0.0001), whereas 80 minutes after decompression changes tended to return to baseline (0.36, SD 0.03; p=0.001). There was no statistically significant change in heart rate, ET, and systolic pulmonary artey pressure directly after the dive compared to baseline. There were no gas microbubbles detectable during or after decompression.

CONCLUSIONS: Simulated hyperbaric dry chamber dives were associated with a transient decrease of AT/ET in apparently healthy men. Factors other than immersion, cold or gas microbubbles may contribute to acute changes in cardiac function after single scuba dives.

668 June 1 1:15 PM - 1:30 PM

The Effects of High Intensity Interval Training on Systemic and Cardiac Parameters in a Mouse Model of Diabetic Cardiomyopathy

Justin Dials, Ph.D.1, Mark Ziolo, Ph.D.2, Brian Focht, Ph.D., FACSM2, Nathan Saunders2, Steve Roof2, Joseph Ostler2, Lucas Citro2, Peter Mohler, Ph.D.2, Steven T. Devor, Ph.D., FACSM2. 1Capital University, Columbus, OH. 2The Ohio State University, Columbus, OH.

(No relationships reported)

The exact cause of cardiac dysfunction in diabetic cardiomyopathy is not fully elucidated and may involve impaired cardiac insulin-mediated Akt signaling. Evidence suggests that exercise training may improve cardiac function in models of diabetic cardiomyopathy. The pathways underlying exercise-induced improvements in cardiac function are not known and may involve changes in insulin-mediated Akt signaling.

PURPOSE: To determine the underlying mechanisms of diabetic cardiomyopathy as well as systemic and cardiac related adaptations to exercise training in db/db mice.

METHODS: 24 male db/db mice completed the 8 week intervention (12 exercise; 12 sedentary).

RESULTS: We revealed baseline differences (p<0.05) in insulin-mediated Akt signaling between healthy mice db/db mice. Following the intervention, exercise-trained db/db mice exhibited greater (p<0.05) glucose control compared with sedentary db/db mice. Further, exercise training resulted in greater improvements (p<0.05) in max VO2 in db/db mice compared with sedentary counterparts.

CONCLUSION: We have shown that impaired cardiac insulin-mediated Akt signaling is evident in db/db mice. We have also documented that short-term high intensity exercise training is effective at improving max VO2 in db/db mice. Further, we have illustrated that exercise-trained db/db mice exhibit better systemic glucose control compared with sedentary db/db mice. These findings illustrate the potential impact of cardiac insulin signaling on diabetic cardiomyopathy and the importance of exercise training on systemic glucose control and functional capacity.

669 June 1 1:30 PM - 1:45 PM

α-adrenergic Vasoconstriction Contributes To The Age-related Increase In Conduit Artery Retrograde And Oscillatory Shear

Darren P. Casey1, Jaume Padilla2, Branton G. Walker1, Essa A. Mohamed1, Michael J. Joyner, FACSM1. 1Mayo Clinic, Rochester, MN. 2University of Missouri, Columbia, MO.

(No relationships reported)

Aging is associated with greater presence of retrograde and oscillatory shear in peripheral conduit arteries of humans. We previously demonstrated that reduced nitric oxide bioavailability in the resistance vessels contributes, in part, to the age-related alterations in shear rate patterns.

PURPOSE: To further elucidate the potential mechanisms for age-related discrepancies in shear patterns, we examined the contribution of α-adrenergic vasoconstriction in resistance vessels on shear rate profiles in upstream conduit arteries of younger (n=8; 5M/3F, age 27 ± 2 years) and older (n=11; 6M/5F, age 68 ± 2 years) healthy adults.

METHODS: Brachial artery diameter and velocities were measured via Doppler ultrasound during 1) rest (control), 2) sympathetic activation via lower body negative pressure (LBNP; -20mmHg), and 3) intra-arterial administration of phentolamine (non-specific α-adrenergic antagonist).

RESULTS: At rest older adults exhibited greater brachial artery retrograde and oscillatory shear (-9.9 ± 2.7 s-1 and 0.11 ± 0.03 arbitrary units, respectively) compared with younger adults (-3.1 ± 1.0 s-1 and 0.05 ± 0.02 arbitrary units, respectively; P < 0.05 for both). LBNP increased brachial artery retrograde and oscillatory shear in young (-6.7 ± 2.1 s-1 and 0.10 ± 0.02 arbitrary units, respectively, respectively; P < 0.05 vs. control) but not older adults (-9.1 ± 2.4 s-1 and 0.12 ± 0.02 arbitrary units, respectively; P = 0.85-0.97 vs. control). With phentolamine retrograde and oscillatory shear were abolished in young adults (-0.2 ± 0.2 s-1 and 0.00 ± 0.00 arbitrary units, respectively; P < 0.05 vs. control) and markedly reduced, however still persistent, in older adults (-3.8 ± 0.9 s-1 and 0.02 ± 0.01 arbitrary units, respectively; P < 0.001 vs. control).

CONCLUSIONS: Our data indicate that α-adrenergic vasoconstriction substantially contributes to age-related discrepancies in conduit artery shear rate patterns at rest.

670 June 1 1:45 PM - 2:00 PM

Larger Decrease In Endothelial Function After Ischemia-reperfusion Injury In Heart Failure Patients

Dick H.J. Thijssen, Joost Seeger, Nathalie Benda, Maria Hopman, FACSM. Radboud University Nijmegen Medical Centre, nijmegen, Netherlands.

(No relationships reported)

Ischemia-reperfusion(IR)-injury is a potentially harmful event that causes damage to the endothelium. Larger IR-injury on the endothelium is clinically related to poorer prognosis after ischemic (myocardial) events. Recent data indicate that advanced age is associated with a larger damage of IR-injury on the endothelium. Also heart failure (HF), typically associated with endothelial dysfunction and poor clinical outcome, may demonstrate exaggerated endothelial injury after IR-injury.

PURPOSE: To examine the impact of IR-injury on the endothelial function in patients with HF and their age- and sex-matched controls.

METHODS: We examined brachial endothelial function before and after IR injury in patients with HF (n=8, 63±11 years) and healthy age-matched controls (n=12, 63±9 years). All HF patients were classified as New York Heart Associated-class II/III and were on optimised pharmacological treatment. Endothelial function was examined using the flow-mediated dilation (FMD). IR-injury was induced by 5 minutes of ischemia with handgrip exercise, followed by 15 minutes of reperfusion. Ischemic handgrip exercise induces a significant ischemic stimulus that results in a reactive hyperaemic response that is assumed to represent a peak response.

RESULTS: Baseline FMD% was not different between HF and controls (7.2±4.0 versus 5.3±1.7%, respectively). IR-injury resulted in a significant decrease in FMD% in HF patients and healthy controls, demonstrating that this stimulus leads to endothelial damage (p<0.001). Interestingly, patients with HF demonstrated a significantly larger decline in FMD after IR-injury (54%) than healthy controls (26%; 2-way ANOVA interaction-effect;p=0.014).

CONCLUSIONS: Our data demonstrate, for the first time in humans, that patients with HF demonstrate a larger decline in endothelial function after IR-injury than their healthy peers. This larger vulnerability to IR-injury was independent of baseline endothelial function and present under optimal pharmacological treatment. These results may partly explain the poor clinical outcome in heart failure patients for cardiovascular events.

671 June 1 2:00 PM - 2:15 PM

Effects Of Isometric Hand Grip Contractions On Prefrontal And Vastus Lateralis Hemodynamic Responses At Different Cycling Intensities

Yagesh Bhambhani1, Swapan Mookerjee2. 1University of Alberta, Edmonton, AB, Canada. 2Bloomsburg University, Bloomsburg, PA. (Sponsor: Dr. Robert Haennel, FACSM)

(No relationships reported)

PURPOSE: Numerous activities of daily living require simultaneous contractions of multiple muscle groups at different intensities. However, the interaction of the hemodynamic responses during these complex contractions is poorly understood. This study examined the localized changes in oxyhemoglobin (HbO2), deoxyhemoglobin (HHb) and total Hb (HbO2 + HHb) (collectively referred to as hemodynamic responses) measured by near infrared spectroscopy (NIRS) during intermittent isometric handgrip contractions (IHG) while cycling below the ventilatory (VT) and respiratory compensation (RCT) thresholds.

METHODS: Ten healthy males cycled at 10% below the VT and RCT for 5 mins at each intensity. During the final minute, they performed 10 maximal IHG. NIRS was used to examine the acute changes in hemodynamic responses at the left prefrontal (PF) and right vastus lateralis (VL) throughout exercise. Cardiac output (Q) was measured non-invasively by CO2 rebreathing prior to and following the IHG at each intensity.

RESULTS: During the IHG at both cycling intensities: (i) PF HbO2 and total Hb demonstrated additional increases (P<.05) implying enhanced blood flow and neuronal activation, (ii) VL HbO2 and total Hb did not demonstrate any additional changes (P>.05) implying that localized blood flow and oxygen extraction were unaffected, (iii) Q increased by 7% and 8 % at VT and RCT respectively (P<.05 in each case) during the IHG when compared to the pre IHG values implying increased systemic blood flow and oxygen availability, and (iv) there were no significant differences between the two intensities for any of these responses.

CONCLUSIONS: Addition of IHG during steady state cycling enhances cortical activation and cerebral blood flow without compromising VL muscle hemodynamic responses. The additional metabolic demands of IHG are met by enhanced systemic circulation. These responses are independent of exercise intensity, implying that the neuronal efficiency of such complex muscle contractions is unaltered at intensities below the RCT.

672 June 1 2:15 PM - 2:30 PM

Are There Sex-specific Differences In The Mechanoreflex That Alter Limb Movement-induced Hemodynamic Responses?

Stephen J. Ives1, John McDaniel2, Melissa A.H. Witman1, Anette S. Fjeldstad1, D. Walter Wray1, Russell S. Richardson1. 1University of Utah, Salt Lake City, UT. 2Kent State University, Kent, OH.

(No relationships reported)

Previous studies have determined that pre-menopausal females exhibit an attenuated metaboreflex, however little is known about sex-specificity of the mechanoreflex.

PURPOSE: Thus, we sought to determine if there are sex differences in terms of passive limb-movement induced central and peripheral hemodynamic responses.

METHODS: Second-by-second measurements of heart rate (HR), stroke volume (SV), cardiac output (CO), mean arterial pressure (MAP), and femoral artery blood flow (FBF) were recorded during 3 min of supine passive knee extension in 24 young healthy subjects (12 females, 12 males).

RESULTS: Centrally, females had lower baseline values for SV (73±4 vs. 104±9 mL/beat), CO (4.5±0.3 vs. 5.7 ±0.5 L/min) (p<0.05), while peripherally femoral artery blood flow and vascular conductance was similar between the sexes. In response to passive limb movement, females displayed an attenuated peak central response, as HR (9.2±1 vs. 14.8±2 %Δ), SV (4.5±0.6 vs. 7.8±1.2 %Δ), and CO (10.0±1 vs. 17.2±2 %Δ), were lower in females (p<0.05). Passive limb movement-induced similar increases in peak FBF (315±51 vs. 375±42 mL/minΔ) and peak femoral vascular conductance (FVC; 3.8±2 vs. 4.4±2 ml/min/mmHgΔ) in both sexes (females vs. males, respectively).

CONCLUSION: Although females exhibit both similar movement-induced hyperemia and peripheral vasodilatory function, they have a significantly reduced central hemodynamic response to this stimulus, implying attenuated afferent signaling via mechanoreceptors. This study reveals that, as with the metaboreflex, a sex-specific attenuation of the mechanoreflex may play a role in differing hemodynamic responses to exercise in males and females. Supported by: NIH PO1 HL-091830.

F-19 Free Communication/Slide - Diet, Exercise, and Body Composition in Athletes

JUNE 1, 2012 1:00 PM - 2:15 PM

ROOM: 2016

673 Chair: Michelle T. Barrack. University of California Davis, Davis, CA.

(No relationships reported)

674 June 1 1:00 PM - 1:15 PM

Diet Patterns, Anthropometric Measures, Bone Density And Injury Among Male Adolescent Runners And Non-runner Athletes

Michelle T. Barrack, Christina Giacomazzi, Frank A. Barrack, Aurelia Nattiv, FACSM. University of California, Los Angeles, Los Angeles, CA.

(No relationships reported)

It is important to identify diet and exercise behaviors that promote bone mineral accrual and reduce bone stress injury risk among males during the teenage years.

PURPOSE: Assess interrelationships between exercise activity, diet, bone density, and fracture risk in a sample of male adolescent athletes.

METHODS: Twenty-seven male adolescents (9 endurance runners and 18 non-endurance runner athletes) age 16.1 ± 0.2 y completed a study questionnaire (assessing diet patterns, sports participation history, fracture risk, and body weight/shape perceptions), had their height and weight measured, and underwent a dual-energy x-ray absorptiometry scan to evaluate body composition and bone density of the total body and lumbar spine. Endurance-runners ran high school cross-country; non endurance-runner athletes participated on a competitive soccer, volleyball, or basketball team.

RESULTS: Male runners compared to non-runners were lighter (19.3 ± 0.8 kg/m2 vs. 22.0 ± 0.6 kg/m2, p<0.05), leaner (10.5 ± 1.0% vs. 14.3 ± 0.7% fat, p<0.005), and fewer reported gaining five or more pounds in the past year (38% vs. 93%, p<0.005). Runners and non-runners reported a non-different number of meals per day (3.1 ± 0.2 vs. 3.3 ± 0.1, p=0.43), however runners had a lower number of snacks (2.1 ± 0.4/day vs. 3.3 ± 0.3/day, p<0.012). Fewer male runners than non-runners had a snack within 30 minutes of finishing exercise (22% vs. 98%, p<0.001). Runners’ lumbar spine BMC and BMD Z-score values were less than non-runner athletes 57.3 ± 4.2 g vs. 67.5 ± 3.0 g, p=0.06 (trend) and -0.23 ± 0.26 vs. 0.68 ± 0.19, p=0.01, respectively. There was a trend toward a higher percent of runners compared to non-runner athletes with a BMD Z-score < -1.0 (33.3% vs. 5.6%, p= 0.055). A higher percent of runners had a history of stress fracture (22.2% vs. 0%, p= 0.049).

CONCLUSIONS: Male athletes’ sports involving high-impact short-duration movements may favor bone mineral gains more than the moderate-impact continuous loads of distance running. Male runners’ lower bone density may have resulted from a calorie intake not sufficient to replenish energy expended from exercise or allow for normal growth. Future prospective studies are needed to identify relationships between sport-type, diet, and bone mineral accrual in the male athlete.

Supported by UCLA GCRC Grant #M01-RR000865

675 June 1 1:15 PM - 1:30 PM

Changes Of Key Hormones And Muscle Mass During Positive Or Negative Energy Balance In Athletes

Ina Garthe1, Truls Raastad2, Jorunn Sundgot-Borgen2. 1Norwegian Olympic Sports Centre, Olso, Norway. 2Norwegian School of Sports sciences, Olso, Norway.

(No relationships reported)

During weight loss and weight gain, changes in body composition may be influenced by changes in hormonal status.

PURPOSE: To investigate how key hormones are altered during positive or negative energy balance and how this relates to changes in muscle mass.

METHODS: Fourteen elite male athletes were randomized into two groups; weight loss (WL, n=5) and weight gain (WG, n=9). Intervention varied from 6 to 12 weeks, depending on the weight change. Both groups completed four sessions of strength training·week-1. DEXA and fasting blood samples were taken at rest, before and after the period of weight regulation. Testosterone, IGF-I and cortisol were analyzed.

RESULTS: Testosterone was not altered in WL or WG. IGF-I remained unchanged in WL, but decreased in WG by 15 ± 5%. Cortisol did not change significantly in WL, but was reduced in WG (-11 ± 4 %). Testosterone/cortisol ratio was reduced in WL (-27 ± 7%). A correlation was found between changes in testosterone/cortisol ratio and changes in LBM (r=0.7).

CONCLUSION: Preliminary data indicates that WL only influenced testosterone/cortisol ratio. The correlation between the changes in testosterone/cortisol ratio and the changes in LBM indicates that hormone status influence the change in body composition during weight regulation.

676 June 1 1:30 PM - 1:45 PM

Dietary Intake To Reduce Body Mass Before Competition In German Judo Athletes

Anja Carlsohn, Josefine Weber, Juliane Müller, Anja Stuwe, Steffen Müller, Frank Mayer. University of Potsdam, Potsdam, Germany.

(No relationships reported)

PURPOSE: In US wrestling and other weight category sports, athletes’ body mass management has often been shown to be detrimental to health and/or performance. However, little is known about nutritional practices of German judo athletes during body mass reduction. It was purposed to analyze dietary habits of male and female German division I and II judoka before competition.

METHODS: Dietary intake of 7 female and 5 male judoka (22±3 yr, 1.71±0.10 m, 71.0±11.7 kg) was recorded during maintenance of body mass before the onset of dietary restriction approximately 3 weeks before a competition (MAIN) and once again during body mass reduction in the last three days before the competitive weigh-in (RED). Body mass was recorded before and at the end of each protocol period to calculate loss of body mass. Energy, macronutrient and fluid intake were analyzed using a 3-day dietary protocol with standardized household measures based on the German Food Database (mean±SD, 95% CI).

RESULTS: Athletes reduced their body mass by 3.0±1.5 kg (4.3±2.2% of initial body mass) to achieve the required weight category. During RED, intake of energy (884±574 kcal/d, 95% CI 520-1249 kcal/d), carbohydrates (107±55 g/d, 95% CI 72-141 g/d), protein (37±27 g/d, 95% CI 19-54 g/d) and fat (30±19 g/d, 95% CI 18-42 g/d) was markedly reduced compared to MAIN (energy: 2581±767 kcal/d, 95% CI 2093-3068 kcal/d; carbohydrates: 309±79 g/d, 95% CI 259-359 g/d; protein: 104±50 g/d, 95% CI 73-136 g/d; fat 84±26 g/d, 95% CI 68-101 g/d). Total water consumption from food and fluids was considerably decreased in RED (1431±881 g/d, 95% CI 872-1991 g/d) compared to MAIN (2655±1012, 95% CI 2012-3298 g/d). Relative nutrient intake was calculated as 4.5±1.4 g/kg/d vs. 1.5±0.7 g/kg/d for carbohydrates and 1.5±0.7 vs. 0.5±0.3 g/kg/d for protein during MAIN and RED.

CONCLUSIONS: In German judoka of both genders severe food and fluid restrictions were observed during the last three days before the competitive weigh-in. During body mass reduction, intake of energy, carbohydrates, protein and fluids were considerably below current recommendations for athletes. Thus, nutritional strategies of German elite judoka to achieve the scheduled weight class are similar to those observed in other weight category sports and have the potential to adversely affect health and performance.

677 June 1 1:45 PM - 2:00 PM

Are Body Composition Changes Associated with Energy Expenditure in Elite Junior Basketball Players?

Analiza M. Silva1, Diana A. Santos1, Catarina N. Matias1, Paulo M. Rocha1, Édio L. Petroski2, Claudia S. Minderico1, Luís B. Sardinha1. 1Faculty of Human Kinetics, Technical University of Lisbon, Lisboa, Portugal. 2Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.

(No relationships reported)

PURPOSE: Small changes in resting energy expenditure (REE) can have a huge effect on a person’s total daily energy expenditure (TEE). So far, no research was conducted to clarify the main body composition determinants of REE and TEE in elite athletes, whose goals include achieving a healthier body composition by increasing fat-free mass (FFM) and maintaining fat mass (FM) at an optimal level for competition. Therefore, we aimed to analyze the association between changes in total and regional FM and FFM over a season with REE and TEE in elite basketball players.

METHODS: A total of 8 males and 9 females of the Portuguese basketball team (16-17 yrs) participated in this prospective observational study. At the beginning of the pre-season and at the end of the in-season period, REE was estimated by indirect calorimetry and TEE by the doubly labeled water method whereas total and regional FM, FFM, lean-soft tissue (LST), and bone mineral were assessed by dual energy x-ray absorptiometry. Dietary intake was obtained by a 7-day food record. A handgrip dynamometer was used for maximal isometric strength and a vertical-jump test for explosive power. Changes were expressed as a percentage from the baseline values. Comparison of means and multiple regression analysis were performed.

RESULTS: The REE, REE per FFM units, and TEE increased by 13.2 ± 12.6 %, 11.0 ± 12.9 % and 13.3 ± 12.7 % (p < 0.01), respectively. Raises in FFM (3.6 ± 2.2 %) and reductions in relative FM (-4.0 ± 6.6 %) were observed (p < 0.01). No significant changes were observed in energy and macronutrients intake over the season (p > 0.05). Strength and power increased by 14.4 ± 9.9 % and 9.8 ± 10.6 %, respectively (p < 0.001). Alone, FFM and arms LST differences explained 25 % and 23 % of the total variance in REE alteration. These variables remained associated after adjusting for gender and baseline values (β = 0.536, p = 0.042; and β = 2.023, p = 0.016, respectively).

CONCLUSIONS: Over the season, the REE raise was explained by changes in FFM. The raise in REE per each FFM unit along with the strength and power improvement may suggest that a qualitative change in the metabolic active tissues occurred. Furthermore, these findings highlight the regional LST contribution, specifically located at the upper limbs, as a key component for the higher REE occurred over the season in junior basketball players.

678 June 1 2:00 PM - 2:15 PM

Nutritional Intake Of Male Cyclists On The Day Of A 145 km Event In The Heat

Laura J. Kunces1, Evan C. Johnson1, Colleen X. Munoz1, Jay R. Hydren1, Robert A. Huggins1, Daniel A. Judelson, FACSM2, Mathew S. Ganio3, Jakob L. Vingren4, Brian R. Kupchak1, Jeff S. Volek1, Lawrence E. Armstrong, FACSM1. 1University of Connecticut, Storrs, CT. 2California State University, Fullerton, Fullerton, CA. 3University of Arkansas, Fayetteville, AR. 4University of North Texas, Denton, TX.

(No relationships reported)

Athletes use a variety of nutritional approaches before, during and after ultra-endurance events. Generally, high carbohydrate intakes are encouraged but a variety of nutritional approaches may improve performance and recovery. However, few data exist on the actual caloric and macronutrient intake of athletes participating in ultra-endurance events.

PURPOSE: To document the macronutrient intake of recreational males before, during, and after a 145 km cycling event in the heat.

METHODS: Dietary recalls were performed on 20 recreational male cyclists (age; 48.1 ± 7.7 y, height; 178.2 ± 7.6cm, weight; 84.7 ± 13.6kg) who performed a 145km endurance ride in a 45°C environment in Texas starting at 0600. Pre-race, during exercise, and post-race diet recall and records were recorded. Cyclists self-selected endurance pace and nutritional intake throughout the event day.

RESULTS: Cyclists completed the 145km course in 486 ± 99min. Caloric intake and the percent energy from CHO pre-event were 674 ± 279 Kcal (range: 316-1429 Kcals) and 56 ± 15% CHO (range: 36-84%), respectively. Caloric intake and percent energy from CHO during-event were 1794 ± 840 Kcals (737-3566 Kcals) and 83 ± 9% CHO (65-94%), respectively. Caloric intake and percent energy from CHO post-event were 1821 ± 695 Kcals (486-3431 Kcals) and 45 ± 15% CHO (24-87%), respectively.

CONCLUSION: Although variable between cyclists, these data indicate that on average energy intake the day of an ultra-endurance event consists of a pre-race meal moderate in energy (16% of total daily intake), with the remaining calories equally distributed between the event and recovery. Carbohydrate content was moderate pre-event (∼59%), highest during the event (∼83%), and lowest during recovery (∼45%). The implications of these dietary intakes on performance and recovery require further study.

F-20 Free Communication/Slide - Space/Microgravity

JUNE 1, 2012 1:00 PM - 2:45 PM

ROOM: 3024

679 Chair: James A. Pawelczyk, FACSM. Noll Physiological Research Center, University Park, PA.

(No relationships reported)

680 June 1 1:00 PM - 1:15 PM

Counteracting Decrements in Muscle Function and Aerobic Capacity During Unloading Utilizing a Gravity Independent Device

Joshua A. Cotter1, Theresa Hoang1, Alvin Yu1, Per Tesch2, Vincent J. Caiozzo, FACSM1, Gregory R. Adams1. 1University of California, Irvine, Irvine, CA. 2Mid Sweden University, Östersund, Sweden.

(No relationships reported)

Reduced skeletal muscle strength and endurance, along with reduced aerobic capacity, are risks associated with astronauts’ physical performance during missions. Unilateral lower limb suspension (ULLS) is a ground-based analog to study the effect of unloading in humans that has shown declines in muscle function following brief periods of unloading.

PURPOSE: To determine if a combined aerobic and resistance training program utilizing the Multi-Mode Exercise Device (M-MED), a gravity independent flywheel device, can counteract the decrements in muscle function and aerobic capacity due to unloading.

METHODS: Nine subjects (21 ±1.9 yr, 62.4 ±9.2 kg, 166.8 ±6.7 cm) completed 10 days of unilateral lower limb suspension (ULLS) alone (control) while 10 subjects (21 ±3.0 yr, 68.0 ±14.3 kg, 168.1 ±10.7 cm) performed alternating days of resistance training and high intensity interval rowing with ULLS. Maximal oxygen consumption (VO2max), 3 repetition max (3RM), and isokinetic testing was performed. Resistance training included 4 sets of 7 repetitions of the squat and 6 sets of 15 repetitions of the calf raise exercise. Aerobic rowing consisted of 4x4 minute sets of high intensity rowing at 90% VO2max alternated with 4 minutes of low intensity rowing at 50% VO2max.

RESULTS: Control subjects showed no change in VO2max while a trend towards a 7% increase was seen in trained subjects. Unilateral leg press 3RM remained unchanged in control subjects whereas unilateral calf raise showed a decrease of 9.5%. The training group increased both the leg press and calf raise 3RM by 9.8%. No differences were seen in either groups for isokinetic knee flexion and extension peak torques except for an 8.1% decrease in knee flexion torque at 180 °/sec in the control group. Peak plantar flexor torque decreased at speeds of 30°/sec, 60°/sec, 120°/sec, 210°/sec, and 240°/sec for the control group whereas training prevented these losses. No torque changes were seen during the isokinetic muscular endurance test for the control group. Increased torque of 13.2% was observed for sets 2 and 3 of the 3 set test for the training group.

CONCLUSION: Concurrent aerobic and resistance training on a gravity independent flywheel device successfully prevented performance decrements seen during unloading and may be a feasible device for use in space flight.

681 June 1 1:15 PM - 1:30 PM

Acupuncture Combined with Herb Medicine Maintains Muscle Mass During 21 days of Hindlimb Suspension

Sukho Lee, Junyoung Hong, Kijeong Kim. Texas A & M International University, Laredo, TX. (Sponsor: Minsoo Kang, FACSM)

(No relationships reported)

Muscle atrophy, decrease in size of muscle, has been a major concern for those who experienced microgravity, aging process, neuromuscular disease, and various injuries. Acupuncture and herb have been used predominantly as therapeutic interventions. However, little is known about the effects of these on the skeletal muscle mass and function.

PURPOSE: To investigate whether acupuncture and/or herb medicine can attenuate muscle atrophy induced by hindlimb suspension. METHODS Thirty female SD rats were randomly divided into 5 groups: 1) Control (CON), 2) Hindlimb Suspension (HS), 3) HS + Herb (HSH), 4) HS + Acupuncture (HSA), and 5) HS + Combination of two treatments (HSHA) (n=6 each). Huang Qi (Radix Astragali Membranceus) was given via oral gavage technique once a day for 21 days (1 ml: 368 mg/kg). Electro-Acupuncture (2-15 Hz, 2-4 Voltage for 15 mins) was applied for 3 times/wk for 21 days. All rats received sham treatment. The data were analyzed using one-way ANOVA with Least Significant Difference post hoc test.

RESULTS: 21 days of hindlimb suspension induced atrophy of 32.4% in soleus muscle compared to control group (p<0.05). Mean±SD values are presented in the table below:

Herb itself was not able to attenuate atrophy. However, muscle in HSA was significantly higher than HS (p<0.05). There was no significant difference in soleus muscle mass between CON and HSHA groups indicating that combination of acupuncture and herb treatments prevents muscle atrophy.

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CONCLUSION: Acupuncture with herb medicine could be used to prevent (or attenuate) atrophy of skeletal muscle caused by various reasons including aging, space travel, injury and neuromuscular disease.

Supported by TAMIU URG Grant 2010.

682 June 1 1:30 PM - 1:45 PM

Effect of Acupuncture and Herbal Diet on Skeletal Muscle Contractile Properties of Hindlimb Unloading Rats

Kijeong Kim, Junyoung Hong, Sukho Lee. Texas A & M International University, Laredo, TX. (Sponsor: Minsoo kang, FACSM)

(No relationships reported)

Microgravity induces the muscle atrophy that may affect performance of astronauts during and post flight. Therefore, it is important to find effective interventions for preventing or attenuating muscle atrophy caused by microgravity. Acupuncture has been widely used for the treatment of a variety of diseases. Also, some herb medicines have been shown to alleviate muscle atrophy. There is, however, little evidence on the effect of acupuncture and/or herbal medicine on the skeletal muscle contractile properties in animal model.

PURPOSE: To test whether acupuncture and/or herbal medicine affect muscle contractile properties of hindlimb unloading rat.

METHODS: Thirty female Sprague-Dawley rats were randomly divided into 5 groups: 1) Control (CON), 2) Hindlimb Unloading (H), 3) H+Herb (HH), 4) H+Acupuncture (HA), and 5) H+Combination of two treatments (HC) (n=6 each). Huang Qi (Radix Astragali Membranceus) was given via oral gavage technique once a day for 21 days (1 ml mixed with water based on concentration of 368 mg/kg). Electro-Acupuncture treatment (2-15 Hz, 2-4 Voltage for 15 mins) was applied for 3 times/wk for 21 days. All rats received sham treatment. The data were analyzed using one-way ANOVA with Least Significant Difference post hoc test.

RESULTS: After 21-day hindlimb unloading, lateral gastrocnemius showed significant atrophy in H compared to CON group (614.33±27.72 vs. 799.83±19.95 mg; p<0.05). The muscle mass of lateral gastrocnemius in HA and HC were significantly higher than H showing effectiveness of acupuncture treatment (743.00±46.18 and 726.00±23.59 mg; p<0.05). The isometric tetanic tension was significantly lower in H compared to CON (8.74±0.1.54 vs. 11.93±0.70 N/cm2; p<0.05). However, there was no significant difference in H and HH, HA, and HC. Also, there was no significant difference in isometric twitch tension among the groups (CON: 3.93±0.14,.H: 3.23±0.47, HH: 3.78±0.28, HA: 3.49±0.19, and HC: 3.71±0.19 N/cm2).

CONCLUSION: The acupuncture treatment may alleviate the atrophy caused by 21-day hindlimb unloading of lateral gastrocnemius muscle. Therefore, acupuncture treatment could be used to as countermeasure against atrophy of skeletal muscle caused by various reasons including aging, space travel, injury and neuromuscular disease

683 June 1 1:45 PM - 2:00 PM

Combined Effects of Bed Rest and Hypoxia on Skeletal Muscle Oxidative Function

Desy Salvadego1, Michail E. Keramidas2, Rossana Domenis1, Irene Mavelli1, Ola Eiken2, Igor B. Mekjavic3, Bruno Grassi1. 1University of Udine, Udine, Italy. 2Royal Institute of Technology, Stockholm, Sweden. 3Jozef Stefan Institute, Ljubljana, Slovenia.

(No relationships reported)

PURPOSE: A functional evaluation of skeletal muscle oxidative metabolism was carried out before (CTRL) and after a 10-day normoxic bed rest (BR) and a 10-day hypoxic (PO2 in ambient air 12.5 kPa, corresponding to an altitude of about 4,000 m) BR (H-BR); the latter condition was taken as a simulation of lunar habitats (pilot study for the PlanHab Research Project; Olympic Sport Center, Planica, Slovenia).

METHODS: Twelve healthy young men (age: 24.7±2.1 years [mean±SD]) were evaluated. Pulmonary gas exchange, heart rate (HR), and vastus lateralis muscle fractional O2 extraction (by near-infrared spectroscopy), expressed as a percentage of the maximal values obtained by a transient limb ischemia, were determined during an incremental one-leg knee extension (KE) exercise up to volitional exhaustion. Mitochondrial respiration was evaluated by high-resolution respirometry in “skinned” vastus lateralis fibers obtained by biopsy.

RESULTS: Peak pulmonary O2 uptake decreased by about 6-8% both after BR (0.83±0.11 L·min-1) and H-BR (0.84±0.10) vs. CTRL (0.90±0.10). Skeletal muscle peak fractional O2 extraction was lower after BR (58.4±10.3%) and after H-BR (63.0±13.6) vs. CTRL (68.0±12.4). Maximal ADP-stimulated mitochondrial respiration was higher after H-BR (65.3±32.5 pmolO2·s-1·mg-1 wet weight) vs. CTRL (45.7±6.8); no significant changes were observed between BR (50.4±10.5) and CTRL. Mitochondrial regulation by ADP tended to shift towards a more oxidative type of control after H-BR, as shown by the higher Km for ADP (0.215±0.04 mM) vs. CTRL (0.160±0.04).

CONCLUSIONS: After eliminating, by the KE exercise protocol, constraints related to cardiovascular O2 delivery, peak pulmonary O2 uptake and skeletal muscle peak fractional O2 extraction decreased significantly, by a similar extent, after BR and H-BR. Thus, hypoxia did not affect the well-known impairment of skeletal muscle oxidative metabolism observed in vivo after BR. On the other hand, hypoxia combined to BR seems to improve mitochondrial function ex vivo, possibly as a compensatory mechanism.

Financial support by European Space Agency Programme for European Cooperating States (Contract No. 4000104372/11/NL/KML) and by ASI - OSMA Contract I/007/06/0, WP 1B-32-1.

684 June 1 2:00 PM - 2:15 PM

Orthostatic Hypotension After Long-duration Space Flight: NASA’s Experiences From The International Space Station

Stuart M. C. Lee1, Alan H. Feiveson2, Michael B. Stenger1, Sydney P. Stein3, Steven H. Platts2. 1Wyle Laboratories, Houston, TX. 2NASA Johson Space Center, Houston, TX. 3MEI Technologies, Houston, TX.

(No relationships reported)

Our laboratory previously reported that the incidence of orthostatic hypotension (OH) was greater after long- than short-duration spaceflight in astronauts who participated in Mir Space Station and Space Shuttle missions.

PURPOSE: To confirm and extend these findings, we retrospectively examined tilt test data from International Space Station (ISS) and Shuttle astronauts. We anticipated that the proportion of ISS astronauts experiencing OH would be high on landing day and the number of days to recover greater after long- than short-duration missions.

METHODS: Twenty ISS and 66 Shuttle astronauts participated in 10-min 80° head-up tilt tests 10 d before launch (L-10), on landing day (R+0) or 1 d after landing (R+1). Data from 5 ISS astronauts tested on R+0 or R+1 who used non-standard countermeasures were excluded. Many astronauts repeated the test 3 d (R+3) after landing. Fisher’s Exact Test was used to compare the ability of ISS and Shuttle astronauts to complete the tilt test on R+0. Cox regression was used to identify cardiovascular parameters that were associated with test completion across all tests, and mixed model analysis was used to compare the change and recovery rates between ISS and Shuttle astronauts. In these analyses, ISS data from R+0 and R+1 were pooled to provide sufficient statistical power.

RESULTS: The proportion of astronauts who completed the tilt test on R+0 without OH was less in ISS than in Shuttle astronauts (p=0.03). On R+0, only 2 of 6 ISS astronauts completed the test compared to 53 of 66 (80%) Shuttle astronauts. However, 8 of 9 ISS astronauts completed the test on R+1. On R+3, 13 of 15 (87%) of the ISS and 19 of 19 (100%) of the Shuttle astronauts completed the 10-min test. An index comprised of stroke volume and diastolic blood pressure provided a very good prediction of overall tilt survival. This index was altered by spaceflight similarly for both groups soon after landing (pooled R+0 and R+ 1), but ISS astronauts did not recover at the same rate as Shuttle astronauts (p=0.007).

CONCLUSIONS: The proportion of ISS astronauts who could not complete the tilt test on R+0 due to OH (4 of 6) is similar to that reported in astronauts who flew on Mir (5 of 6). Further, cardiovascular parameters most closely associated with OH recover more slowly after long- compared to short-duration spaceflight.

685 June 1 2:15 PM - 2:30 PM

The Role Of Exercise In Synchronizing The Circadian Timing System During 60 Days Of Bedrest

Alexander Stahn1, Stefan Mendt1, Mathias Steinach1, Oliver Opatz1, Andreas Werner1, Daniel Belavy2, Dieter Felsenberg2, Frank Sattler3, Jochim Koch3, Hanns-Christian Gunga1. 1Center for Space Medicine Berlin, Charité University Medicine, Berlin, Germany. 2Centre of Muscle and Bone Research, Charité University Medicine, Berlin, Germany. 3Draegerwerk AG & Co. KGaA, Luebeck, Germany.

(No relationships reported)

A growing body of research indicates that any de-synchronization of the circadian timing system can be detrimental to mental and physical health. It has also been reported that regular exercise may serve as an external cue (‘zeitgeber’) to synchronize the circadian timing system to the 24-h day/night cycle.

PURPOSE: (1) To investigate the effect of 60 days of 6-degree head-down tilt bed-rest (HDTBR) and different exercise protocols on circadian rhythm (2) To assess whether rectal and double temperature measurements can be considered as interchangeable methods for determining circadian rhythm during HDTBR.

METHODS: As part of the Berlin Bed-rest Study 2 (BBR2-2) a total of 24 healthy men were grouped to a resistance, a combined resistance (RES) and vibration exercise (VIB), or a control (CON) group and exposed to 60 days of HDTBR. 36-h temperature profiles were determined using both continuous rectal recordings and a recently developed non-invasive heatflux sensor (Double Sensor) placed at the head.

RESULTS: There was a high degree of agreement between Double Sensor and rectal temperature profiles (mesor: 36.8+0.1 vs. 36.9+0.2, p=0.31, acrophase: 5.6+0.2 vs. 5.5+0.2, p=0.74, amplitude: 0.5+0.07 vs. 0.5+0.08, p=0.87). No significant differences could be observed for mesor (p=0.70), acrophase (p=0.67), and amplitude (p=0.23) between the first and final days of bed-rest for the entire group. Visual inspection, however, revealed that CON seemed to suffer from a slight misalignment of circadian rhythm as indicated by decreased amplitudes and higher variability in acrophase and mesor compared to RES and VIB.

CONCLUSIONS: Circadian rhythm can be reliably obtained by employing a new heatflux sensor located at the head (Double Sensor) that allows continuous and non-invasive core body temperature recordings. This approach could be of significant value for the investigation of thermoregulation and circadian rhythm in athletes as well as clinical settings. Furthermore, regular exercise may serve as a valuable ‘zeitgeber’ in synchronizing the circadian timing system to the 24-h day/night cycle.

Supported by grant 14431/02/NL/SH2 from the European Space Agency and grant 50WB0720 from the German Aerospace Center.

686 June 1 2:30 PM - 2:45 PM

Physiological Responses During Simulated Planetary Field Tests

Carl J. Ade, Ryan M. Broxterman, Thomas J. Barstow, FACSM. Kansas State University, Manhattan, KS.

(No relationships reported)

The physical demands of an astronaut performing planetary mission tasks, like any job, can vary depending on the task. To date only 12 men have performed extravehicular activities (EVA) on the moon surface, ranging from taking pictures to collecting geological samples. This small population and the wide variety of activities performed limits our knowledge surrounding the physical cost of performing planetary EVAs.

PURPOSE: To determine the physiologic response to simulated planetary field-tests under 1G conditions. We hypothesized that subjects performing each field test would i) self-select a pace that allowed for the attainment of steady-state heart rate and ii) that the selected heart rate would be similar during different field tests.

METHODS: 9 subjects (25±7 yrs) completed an incremental treadmill test to exhaustion, a 10-km Walkback Test, and a Planetary Navigation Field Test (PNFT) on separate days. The 10-km was conducted on an indoor 200m track. The PNFT consisted of an obstacle course containing 6 tasks; a ladder and stair ascend/descend, agility maneuvers, box lifting, and a rock wall traverse. Subjects were blinded to the distance and time of each field test and were instructed to complete each task as quickly as possible. Heart rate was measured with a Polar HR monitor (RS800CX) and reported as percent of maximum (HRMAX) as determined during the incremental test.

RESULTS: The time-to-complete the 10-km ranged from 45-91 minutes. During the 10-km, heart rate reached a steady state after the first 10% of the run. This steady state heart rate was on average 86±5% HRMAX. The PNFT time-to-complete ranged from 24-54 minutes. During the PNFT, heart rate did not reach a true steady state but fluctuated between 85-90% HRMAX. The average percent HRMAX during the 10-km was not statistically different than the average obtained during the PNFT (85.7±5.0% vs. 88.0±5.4%, p=0.296).

CONCLUSION: These results demonstrate that when performing simulated planetary tasks as quickly as possible, an individual will self-select an exercise intensity equivalent to ≈88% HRMAX, a work pace that is within the heavy exercise intensity domain.

G-24 Free Communication/Slide - Sports Science: Soccer

JUNE 2, 2012 9:00 AM - 11:00 AM

ROOM: 2016

687 Chair: Donald Kirkendall, FACSM. UNC, Cary, NC.

(No relationships reported)

688 June 2 9:00 AM - 9:15 AM

Physical Demands of NCAA Division I Male Soccer Players During Pre-Season Training

Rebecca L. Stearns, Lesley R. Willis, Julie D. DeMartini, Robert A. Huggins, Evan C. Johnson, Kelly D. Pagnotta, Rebecca M. Lopez, Douglas J. Casa. University of Connecticut, Storrs, CT.

( R.L. Stearns: Contracted Research - Including Principle Investigator; Timex.)

While physiological responses to athletic participation are well established, the specific demands of elite, Division I soccer players during consecutive pre-season practices are not well known.

PURPOSE: To evaluate physical demands of NCAA Division I soccer players during preseason practices. Furthermore, we sought to compare how physical demands differ between returning players (RP) and first year players (FP).

METHODS: Twenty-one male NCAA Division I soccer players (mean ± SD, n=21; age: 20 ± 1 yrs, height: 187.5 ± 2.0 cm, body mass: 76.2 ± 5.6 kg) participated in ten practice sessions (145 ± 20 min; WBGT: 22.35 ± 1.0°C) over nine days. Heart rate (HR) and global positioning satellite data were recorded throughout the entirety of each practice to measure total distance covered, maximal velocity (Vmax), maximal heart rate (HRmax), player load, speed zones and average heart rate (HRavg). Players were divided into two groups: FP (n=6; 18 ± 1 yrs, 75.0 ± 5.2 kg, 188.5 ± 2.5 cm) and RP (n=15; 20 ± 1 yrs, 76.7 ± 5.8 kg, 187.1 ± 1.9 cm) for comparison of player experience. Data was analyzed via Pearson’s bivariate correlation and independent t-tests.

RESULTS: Vmax and HRavg were significantly correlated with distance covered (r2=0.25, p≤0.001 and r2=0.19, p≤0.001, respectively). Player load was significantly correlated with HRavg (r2=0.04, p=0.008). FP HRmax was significantly lower than RP (p=0.006). Compared to FP, RP also had a significantly greater number of efforts within the top (>25.2 km*h-1) speed zone, (0.6 ± 1.0 vs.1.2 ± 2.1 respectively, p=0.023) and the lowest (0.7-7.2 km*h-1) speed zone, (138 ± 73 vs. 163 ± 66 respectively, p=0.042). FP and RP had similar number of efforts in the second (19.8-25.2 km*h-1) and third fastest (14.4-19.8 km*h-1) speed zones (5.8 ± 6.6 vs. 6.7 ± 6.1, 22.9 ± 16.3 vs. 24.1 ± 15.6 respectively, p>0.05). Mean efforts for all speed zones and practices were similar for RP (49 ± 64) compared to FP (44 ± 59, p=0.685).

CONCLUSION: HR was a significant indicator of player Vmax, player load and distance covered during pre-season soccer practice. FP HRmax was lower than RP, however this may be explained with the greater number of efforts within top speed zones and overall by RP.

689 June 2 9:15 AM - 9:30 AM

Primary and Secondary Techniques for Reduction in 40-Yard Sprint Times among Female College Soccer Players

Graeme W. Kerby1, Ronald D. Williams, Jr2, Jason D. Wagganer1. 1Southeast Missouri State University, Cape Girardeau, MO. 2Mississippi State University, Starkville, MS.

(No relationships reported)

Improvements in running speed have been attributed to primary and secondary speed training techniques. Primary techniques involve attention to running mechanics and form, while secondary techniques involve resisted or assisted sprinting.

PURPOSE: To compare the effects of pre and post four week speed training protocol on 40-yard sprint times in female collegiate soccer players.

METHODS: Twelve (20+2y) normal weight (BMI: 22.7+3.4 kg·m-2) female Division I collegiate soccer players participated in a four week training protocol which implemented primary and secondary speed training methods. A standard running mechanics program was implemented two times per week and was immediately followed by resisted or assisted sprinting. The primary speed training method focused on running mechanics and form while the secondary speed training method focused on assisted and resisted sprinting (elastic cords and pulling sleds). Sled towing was chosen for resisted sprinting, while elastic towing devices were chosen for assisted sprinting. Forty yard sprint times were assessed pre and post protocol. In order to minimize confounding variables, the pre and post protocol 40-yard sprints were performed at a similar time of the day on an indoor track. The training protocol was implemented after the first training microcyle which included basic endurance/hypertrophy resistance training and basic aerobic conditioning 3 days per week. All analyses were performed using SPSS v17.0 statistical software package. Values are presented as (mean+SEM). Statistical significance was set at p<0.05.

RESULTS: A paired samples t-test showed the four week speed training protocol elicited statistically significant reductions in 40-yard sprint times (p<0.001). The average sprint time decreased by 0.24 seconds (pre=5.46+0.07 vs post=5.22+0.05).

CONCLUSIONS: When applied correctly, a four week speed training protocol of primary and secondary techniques may play a significant role in reducing 40 yard-sprint times in Division I female college soccer players.

690 June 2 9:30 AM - 9:45 AM

A Comparison Between The Polar Team2 and Session_RPE Training Loads in NCAA Soccer Players

Howard S. Gray1, Satoshi Mizuguchi1, L. Scott Calabrese1, Justin D. Meredith1, Christopher J. MacDonald1, Marco Cardinale2, G. Gregory Haff3, Michael W. Ramsey1, Adam L. Sayers1, Michael H. Stone1. 1East Tennessee State University, Johnson City, TN. 2British Olympic Association, London, United Kingdom. 3Edith Cowan University, Joondalup, Australia.

(No relationships reported)

Quantifying training is an important step in the training process. Doing so means that training can be objectively analyzed, appropriate training loads identified, and suitable adjustments made in an attempt to improve performance and reduce the risk of injury and illness.

PURPOSE: This study compared an emerging method of quantifying training, the Polar Team2 Training Load (Team2 TL), with the more commonly known Session-Rating of Perceived Exertion Training Load (S-RPE TL) method.

METHODS: 18 NCAA Division 1 men’s soccer players wore Polar Team2 heart rate monitors (Polar Electro Oy, Kempele, Finland) for all sessions (totalling 125 team sessions) across 6 different training modalities during a 12-week period in the spring season. The supplied software calculated the Polar Team2 TL from the heart rate data. The players rated each session on a modified Borg scale (0-10 RPE), which was subsequently multiplied by training duration to determine the S-RPE TL.

RESULTS: Correlations between session group mean Team2 TL and S-RPE TL scores ranged from very strong to nearly perfect across the 6 different modalities; cycling r = 0.932, running r = 0.888, soccer training r = 0.930, soccer games r = 0.952, performance testing r = 0.919, and weight training r = 0.925. The correlations were weaker but still significant when concerning the individual player sessions: cycling r = 0.894, running r = 0.762, soccer training r = 0.769, soccer games r = 0.698, performance testing r = 0.769, and weight training r = 0.665.

CONCLUSION: The strong relationship indicates that the Polar Team2 TL may be a useful form of monitoring a number of different training modalities in collegiate soccer players. Further research is needed to investigate the use of the Team2 TL for individual and team training assessments and adjustments.

691 June 2 9:45 AM - 10:00 AM

The Comparison of Hamstring-to-Quadriceps Ratios In NCAA Women’s Soccer Players and Healthy Controls.

Nathaniel D.M. Jenkins1, Brennan J. Thompson1, Eric J. Sobolewski2, Eric C. Conchola1, Matthew J. Hawkey1, Ryan E. Fiddler1, Aric J. Warren1, Matt O’Brien1, Kazuma Akehi1, Lee K. Everett3, Jennifer L. Klufa1, Mallory L. Craig1, Jennifer L. Volberding1, Heather R. Boyes1, Crishel Kline1, Pablo B. Costa4, Eric D. Ryan2, Douglas B. Smith1, Joel T. Cramer, FACSM1. 1Oklahoma State University, Stillwater, OK. 2University of North Carolina, Chapel Hill, NC. 3University of Indianapolis, Indianapolis, IN. 4California State University San Bernardino, San Bernardino, CA.

(No relationships reported)

The hamstrings-to-quadriceps (H:Q) ratio has traditionally been used as a tool to assess the risk of knee- or hamstring-related injuries. Low H:Q ratios may signify a greater risk of injury. Furthermore, women may have a greater predisposition for knee-related injuries due to structural and biomechanical differences. Therefore, the H:Q ratio may be particularly important in women’s athletics.

PURPOSE: To assess H:Q ratios in National Collegiate Athletic Association (NCAA) Division I women’s soccer players and compare them to non-athlete controls.

METHODS: Eighteen healthy NCAA Division I women’s soccer players (mean age ± SD = 20 ± 1 yrs; height = 168 ± 5 cm; body mass = 65 ± 5 kg) and thirteen healthy female controls (age = 21 ± 2 yrs; height = 163 ± 6 cm; body mass = 64 ± 8 kg) performed voluntary maximal concentric isokinetic leg extension and flexion muscle actions on a Biodex System 3 dynamometer (Biodex Medical Systems, Inc., Shirley, NY, USA) at 180°s-1. The highest peak torque (PT) value from three consecutive leg extension and flexion repetitions were used to calculate the traditional H:Q ratio. Independent t-tests were used to compare means between the athletes and non-athletes for leg extension peak torque (PTE), leg flexion peak torque (PTF), and H:Q ratio. Microsoft Excel was used for all statistical analyses, and a type I error rate of ≤ 5% was considered statistically significant for all comparisons.

RESULTS: Mean ± SD values for PTE were 79 ± 12 Nm and 69 ± 5 Nm, the PTF were 48 ± 9 Nm and 32 ± 3 Nm, and the H:Q ratios were 0.60 ± 0.08 and 0.47 ± .03 for the athletes and non-athletes, respectively. There was no difference in mean PTE (P = 0.08), but mean PTF and H:Q ratios were significantly lower (P < 0.01) for the non-athletes than the athletes.

CONCLUSION: The H:Q ratios in NCAA Division I women’s soccer players were greater than the non-athlete controls and were equivalent to the minimum ratio suggested to avoid knee- and hamstring-related injuries (H:Q= 0.60). These findings also emphasize the importance of hamstring strength as a factor for improving the H:Q ratio and potentially reducing the risk of injuries. Finally, perhaps important delineating characteristics between NCAA women’s athletes and non-athletes are PTF and the H:Q ratio, which may result from competition and training demands.

692 June 2 10:00 AM - 10:15 AM

The Relationship Between Sports Conditioning and Success in Professional Soccer

Ruediger Reer1, Daniela Stein1, Kai Wellmann1, Serge P. von Duvillard, FACSM2, Klaus-Michael Braumann1. 1University of Hamburg, Hamburg, Germany. 2University of Salzburg, Salzburg, Austria.

(No relationships reported)

Expert suggest that since 1990‘s there has been a steady increase in performance demand as well as performance level in professional soccer players. The endurance conditioning level of the German national players in the 1990’s is similar to the conditioning of the 3rd division players today. In contrast to endurance performance, the sprint performance level of the national players in the 1990`s is achieved only in the 1st professional soccer division today.

PURPOSE: Based on multiyear record keeping, data collection, and observations, we investigated how to improve, maintain, and enhance the sport specific endurance, speed, and strength that are prerequisites for successful professional soccer players.

METHODS: We conducted numerous seasonal tests with a group of professional soccer players. The tests were soccer specific endurance, sprints, jumps and strength training of specific muscle groups. In addition to soccer specific demands, we designed and implemented individually tailored strength and interval training. This type of training was conducted 3-4 hours per week.

RESULTS:There were statistically significant improvements in soccer specific endurance from the beginning of the 3rd division 4.11+0.19 m/s to 4.26+0.2 (P<0.01) at entry to 2nd division and improved to 4.62+0.25 m/s (P<0.001) at the start of the 1st division. Similar results were observed for 30m sprints. They improved their sprint performance time from the beginning of the 3rd division to 2nd division from 4.27+0.23s to 4.1+0.14s (P<0.01). At entry to 1st division they improved their sprint time to 4.0+0.15s (P<0.001). However, there was no significant difference for counter movement jumps (38.0±3.5cm to 39.2±4.2cm).

CONCLUSIONS: The performance of a professional soccer team depends on multitude of factors. The results suggest that systematic and individualized improvements in soccer specific endurance and sprint performance greatly contribute to the success in professional soccer. In addition, our results suggest that players possess physiological abilities that can be harvested and thus can greatly benefit individually and collectively from training methods employed in this investigation.

693 June 2 10:15 AM - 10:30 AM

Changes in Measures of Power in NCAA Division I Female Soccer Athletes Through Competitive Seasons

Christopher MacDonald, Ryan Alexander, Adam Sayers, Howard Gray, Michael Israetel, Jeremy Gentles, Aaron Casey, Matt Sams, Hugh Lamont, Michael Ramsey, Michael Stone. East Tennessee State University, Johnson City, TN.

(No relationships reported)

PURPOSE: The purpose of this work was to use jump analysis as a practical method of measuring athletic performance and improvements.

METHODS: Females athletes were assessed during maximal effort countermovement (CMJ) and static jumps (SJ), in both unloaded and loaded conditions. Testing occurred prior to and 5 weeks into two consecutive competitive seasons. Testing also included anthropometric assessments (height, body mass, % body fat) and hydration status (urinary specific gravity; USG). Variables considered for each maximal jump trail were: jump height (cm), peak force (N), peak velocity (m/sec), peak power (Watts), net impulse (N*sec), force @ peak power (N), & velocity @ peak power (m/sec) were analyzed during the jumps. Any differences between time points were assessed via a series of one-way ANOVAs. The nature of any between group differences was highlighted using a Bonferroni post hoc test. A significance level of p ≤ 0.05 was set a priori.

RESULTS: Results indicated statistically significant increases in the following jump attributes: USG (p = 0.005; fall pre to fall post), 0kg CMJ peak velocity (p = 0.031; spring post to fall post), 0kg CMJ net impulse (p = 0.019; spring post fall post), 0kg CMJ velocity @ peak power (p = 0.017; spring post to fall post), 11kg CMJ peak velocity (p = 0.050; spring post to fall post), 11kg CMJ net impulse (p = 0.036; spring post to fall post), and 11kg CMJ velocity @ peak power (p = 0.029; spring post to fall post).

CONCLUSIONS: Results indicate that there is a substantial decrease in measurable athletic attributes during the NCAA mandated period of restricted coaching hours that could lead not only to a decrease in performance, but also to a possible increase in incidence of injury. The lack of allowance of structured training will only exacerbate the issue, leaving the athletes, at best, vulnerable to injury upon re-entering regimented, albeit scientifically sound programmed, planned, and executed training and competition schedules.

694 June 2 10:30 AM - 10:45 AM

Pre-season Training And Cardiac Autonomic Indices In Elite Spanish Soccer Players

Daniel A. Boullosa1, Fábio Y. Nakamura2, Laurinda Abreu3, Rubén Crespo-Sánchez4, ·Eduardo Domínguez4, Anthony S. Leicht5. 1Universidade Católica de Brasília, Brasília, Brazil. 2Universidade Estadual de Londrina, Londrina, Brazil. 3Lavadores, Vigo, Spain. 4Universidade de Vigo, Pontevedra, Spain. 5James Cook University, Townsville, Australia.

(No relationships reported)

PURPOSE: To evaluate changes in performance and cardiac autonomic control (i.e. heart rate [HR] variability [HRV]) in elite soccer players during their pre-season training regime.

METHODS: Eight Spanish Premier League soccer players were examined at the first (week 1) and the last week (week 8) of the pre-season period (July-September). Nocturnal HR recordings on 4 days per week were averaged to evaluate the weekly HRV. Players also completed the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) for the assessment of specific fitness.

RESULTS: During the pre-season period, there was no significant change (4.5 ± 23.9%) in Yo-Yo IR1 performance (2,475 ± 421 vs. 2,600 ± 786 m, p=0.55), while there was a significant decrement (6.3 ± 4.3%) in maximal HR (HRmax) recorded during the test (191 ± 7 vs. 179 ± 8 bpm, p = 0.004). Over the 8-week pre-season, significant increases in the standard deviation of the long-term continuous HRV (SD2) (174 ± 56 vs. 212 ± 53 ms, p = 0.017), and in the standard deviation of all HR intervals (SDNN) (135 ± 50 vs. 163 ± 41 ms, p = 0.023) were noted. No significant correlations were identified between Yo-Yo IR1 and HRV measures at week 1. In contrast, Yo-Yo IR1 performance was significantly correlated with SDNN (r =0.89, p=0.007) and SD2 (0.92, p=0.003) at week 8. Greater values in HRV at week 1 were substantially associated with lower HRV changes at the end of pre-season (r values ranged from -0.79 to -0.98, p< 0.05). Furthermore, HRV changes were significantly correlated with decreases in HRmax during the pre-season (r values from 0.83 to 0.94, p<0.05).

CONCLUSIONS: The current results confirm that despite minimal changes in specific fitness (i.e. Yo-Yo IR1), pre-season training significantly improved various HRV indices in elite soccer players with greater changes evident for those with lower initial HRV levels. Nocturnal HRV may provide an important monitoring tool for identification of cardiovascular function changes in top-class soccer players during pre-season regimes.

695 June 2 10:45 AM - 11:00 AM

The Effect Of high and low intensity Half Time Re-warm-up Strategies On Second Half Sprint Performance In Soccer.

Clare Pheasey, Fraser Houston. Manchester Metropolitan University, Crewe, United Kingdom. (Sponsor: Keith George, FACSM)

(No relationships reported)

Soccer players perform less high-intensity running during the opening phase of the 2nd half (Krustrup & Bangsbo, 2001: JSS, 19(11), 881-891;). Although the cause is unknown, research suggests the conventional routine of resting for the entire half-time interval may not provide optimal preparation for the second half (Mohr et al., 2005: Journal of Sports Sciences, 23(6), 593-599). Both Ozyener, Rossiter, Ward, & Whipp (2001: Journal of Physiology, 533, 891-902) and Mohr et al. (2004: Scandinavian Journal of Medicine and Science in Sports, 14(3), 156-162) have demonstrated benefits of a high intensity re-warm up (70% VO2max. and 70% peak HR, respectively), it remains to be seen whether low intensity re-warm up is also effective.

PURPOSE: To determine whether low intensity re-warm up is effective in maintaining sprint performance.

METHODS: Following a standard warm up 9 university 1st team soccer players (mean ±SD, age 20.5 ± 2.1yrs, body mass 74.1 ± 4.2kg and stature 176.4 ± 8.4cm) performed a set of repeated sprint tests (RST1) with photoelectric timing gates placed at 5m and 10m; followed by a 45 minute 11 a-side soccer match. Half-time consisted of 7 minutes of seated rest followed by 7 minutes of a randomly assigned routine; seated rest (SR); cycling at 50% HRmax (C50); or cycling at 70% HRmax (C70). On completion of the half-time period a second Repeated Sprint Test (RST2) was performed. A repeated measures design was employed, requiring participants to report for testing on 3 occasions within a 14 day period.

RESULTS: Results showed a significant difference (p=0.037) over 5m between SR and both active routines.

CONCLUSIONS: Both routines maintained 5m RST performance, suggesting positive benefits to low intensity exercise at half-time.

G-25 Free Communication/Slide - Tendon/Connective Tissue

JUNE 2, 2012 9:00 AM - 11:00 AM

ROOM: 2020

696 Chair: Jim Macintyre, FACSM. Center for Orthopedic and Rehabilitation Excellence at Jordan Valley Hospital, West Jordan, UT.

(No relationships reported)

697 June 2 9:00 AM - 9:15 AM

The Influence of External Loading on Tendon Behaviour in Knee Extensor Stretch-Shorten Cycle Exercise

Jacob E. Earp, Anthony J. Blazevich, Prue Cormie, Robert U. Newton. Edith Cowan University, Perth, Australia.

(No relationships reported)

Tendons contribute to stretch shortening cycle (SSC) performance and their role is determined by their mechanical properties. Tendons are viscoelastic, so the faster a tendon is strained the more the tendon will resist lengthening. While these properties have been demonstrated in modelling studies there is limited evidence in vivo. Rather, in vivo observations of tendon behaviour in sprinting and jumping have shown that as intensity increases tendon strain increases and muscle strain decreases.

PURPOSE: To determine the influence of loading on tendon behaviour during SSC knee extensions.

METHODS: Fifteen men (n=8) and women (n=7) performed single-leg, maximal intensity isoinertial leg extensions at loads of 20 and 90% of their one repetition maximum (1RM). Leg extensions were performed with a full countermovement, during which vastus lateralis (VL) fascicle behaviour was recorded using ultrasonography (95 Hz sampling rate). Muscle tendon unit (MTU) length was estimated by entering electronic goniometer derived-knee joint angles into a previously published model. Quadriceps tendon lengthening-shortening was estimated by subtracting the displacement of the aponeurosis-fascicle insertion from MTU length. VL rate force development (RFD) was calculated using inverse dynamics. RFD- and tendon length-time curves were compared between loads using repeated measures MANOVA with Bonferroni post-hoc tests (p ≤ 0.05).

RESULTS: Peak force and RFD were significantly greater under the 90% 1RM load. The 20% 1RM load resulted in significantly greater tendon lengthening at the end of the eccentric phase (42-50% of normalized time) then the 90% 1RM load. There was also a trend toward (p = 0.052-0.074) greater tendon shortening (recoil) during the concentric phase (74-80% of normalized time).

CONCLUSION: With the lighter load, tendon strain curves matched movement RFD, demonstrating that as the RFD increased the tendon lengthened and as RFD decreased the tendon shortened. However, with the heavier load tendon strain decreased while muscle strain increased despite the greater force and RFD. These data reveal a substantial increase in tendon stiffness as loading rate is increased and suggests that tendon behaviour switches from a power amplifier at light loads to a rigid force transducer at heavier loads.

698 June 2 9:15 AM - 9:30 AM

In Vivo Patellar Tendon Mechanical Properties In Body Builders

Olivier R. Seynnes1, Sigitas Kamandulis2, M Brazaitis2, A Skurvydas2, Marco V. Narici3. 1Norwegian School of Sport Sciences, Oslo, Norway. 2Lithuanian Academy of Physical Education, Kaunas, Lithuania. 3Manchester Metropolitan University, Manchester, United Kingdom.

(No relationships reported)

Animal studies indicate that combined androgenic-anabolic steroids (AAS) and chronic loading affects tendon collagen metabolism and ultrastructure, resulting in increased toe limit strains and brittleness. Despite the high incidence of tendon injury/rupture in body builders and the prevalence of AAS abuse in this population, the combined effects of long-term resistance training and ASS on their tendon mechanical properties have never been studied.

PURPOSE: The aim of this prospective study was to determine the combined effects of long-term loading and ASS abuse on the patellar tendon mechanical properties.

METHODS: Nine male bodybuilding athletes (BBA, 30 ± 5 yrs, 178 ± 4 cm, 93 ± 14 kg) reporting regular parenteral administration of AAS and an age-matched control group (recreationally active, n=7) were recruited for the study. Body builders had been involved in heavy resistance training for several years (12 ± 5 yrs), with one or two competition per year. Tendon size, stiffness, Young’s modulus and toe-limit elongation were measured in vivo, from synchronised ultrasonographic and dynamometry data.

RESULTS: Tendon mean cross-sectional area was 18% larger in BBA than in controls. Stiffness and modulus calculated near maximal tendon force were considerably higher in BBA than in control subjects (4027 vs. 2569 N.m-1, and 1.63 vs. 1.21 GPa, respectively, P<0.05). However, differences in elastic modulus lost significance when mechanical properties were examined at a common force level. Importantly, neither maximal toe limit elongation nor strain differed between groups.

CONCLUSIONS: The patellar tendon of BBA exhibits mechanical properties that are in line with adaptations described in previous training studies. The present lack of change in toe limit elongation in BBA does not substantiate previous reports showing changes in collagen bundle crimp pattern in animals supplemented with AAS. These results suggest that the high occurrence of tendon injury in this population may be linked to the adverse effects of AAS on tissue remodelling, rather than changes in collagen ultrastructure.

699 June 2 9:30 AM - 9:45 AM

The Effect Of Exercise, In The Form Of A 1 Hour Run, On Both The Micro-vascularisation In The Achilles Tendon, And Muscle Fibre Activation In The Lower Leg Muscles Of Patients With Chronic Tendon Injury

Jessica Pingel1, Adrian Harrison1, Lene Rørdam2, Charlotte Suetta2, Jens Bülow2, Henning Langberg2. 1University of Copenhagen, Copenhagen, Denmark. 2Bispebjerg Hospital, Copenhagen, Denmark.

(No relationships reported)

BACKGROUND: Achilles tendinopathy is a very common, painful and treatment resistant disorder. Despite the extent of the problem, very little is known about the pathogenesis of tendinopathy.

PURPOSE: The aim of the present study was to test the hypothesis that tendinopathy arises as a result of increased microvascularisation. Furthermore, an aim of this research has been to investigate the muscle activation pattern of the Gastrochnemius and Soleus muscles, as well as the stiffness of the Achilles tendon, over the period of a 1 hour run in healthy subjects and in tendinopathy patients.

METHODS: Contrast Enhanced Ultrasound (CEU) measurements of microvascular volume (MV) in the Achilles tendon were made as determined using the contrast medium SonoVue in connection with an Ultra-Sound analysis. Analysis were made prior to exercise, immediately after a 60 minute run on a treadmill, and 24 hours after exercise in 16 subjects (n=8 Chronic Achilles Tendinopathy Patients); (n=8 age, gender and BMI matched control subjects). sEMG signals were obtained and recorded continuously during the 60 minute run.

RESULTS: A significant difference between the groups were observed (P<0.05). Furthermore the MV of the Achilles tendon increased significantly after exercise in both groups ( healthy [AU] pre: 0.37±0.1; post 1.63±0.2*), (patients [AU]: pre 1.69±0.5; post 2.51±0.7*). While the MV decreased almost to baseline level after 24 hours (healthy 24h post [AU]; 0.72±0.2), the patients experience a further increase of the MV (2.73±0.9). Moreover, the stiffness of the Achilles tendon in relation to muscle contraction, as assessed using the sEMG to Achilles Tendon Peak Artefact (αmSec) which is in the range of 466 ± 25 mSec (n=6) for healthy subjects, is typically reduced by more than 70% in patients with severe tendinopathy.

CONCLUSIONS: The present data reveal that a 60 minute period of acute exercise increases the MV in the Achilles tendon in both healthy subjects and in patients. Moreover, patients have a significantly larger MV in their Achilles tendon both at rest and also during and after exercise cf healthy subjects, supporting the hypothesis that microvascular changes play a role in the pathogenesis of tendinopathy. Furthermore the present study supports that the tendon flexibility is affected in chronic tendinopathy patients.

700 June 2 9:45 AM - 10:00 AM

Structural And Physiological Changes In Chronically overused Achilles tendons

Henning Langberg1, Jessica Pingel1, Ulrich Fredberg2, Klaus Qvortrup3, Jytte Overgaard4, Michael Kjaer1. 1Institute of Sports Medicine - Copenhagen, Copenhagen NV, Denmark. 2Silkeborg Sygehus, Silkeborg, Denmark. 3Panum Institute - Copenhagen, Copenhagen, Denmark. 4Panum institute - Copenhagen, Copenhagen NV, Denmark.

(No relationships reported)

PURPOSE: The aim was to elucidate to what extent tendinopathy initiates focal physiological and structural changes.

METHODS: Geneexpression and structural parameters were analysed in Achilles tendon biopsies. Eighteen (expression-study) and fourteen (structural-study) Achilles Tendinopathy patients respectively with chronic tendinopathy (> 6 mth of symptoms) of the Achilles tendon were included. Biopsies from the symptomatic Achilles tendon were taken, one from the area related to the pathology based on clinical examination and ultrasound diagnostics and one from the healthy area 4 cm away from the injury respectively. Structural parameters e.g. fibril density, fibril size, cell number and cellular faction were measured using TEM. Gene expression (mRNA levels) of growth factors and structural elements were determined.

RESULTS: Collagen 1, Collagen 3, Fibronectin, Tenascin C, TGF-b and Fibromodulin was significantly increased in the tendinopathic area of the Achilles tendon. Decorin showed a tendency of decrease in the tendinopathic tissue. This indicates a higher collagen synthesis in tendinopathy. Additionally MMP-2, MMP-9 and TIMP 2 were significantly increased in the tendinopathic tissue with no changes observed in TIMP-1, indicating a higher collagen breakdown in tendinopathy. Fibrillogenesis is not present in tendinopathy scleraxis, lysyl oxidase and tenomodulin were not significantly different. Furthermore bFGF, cmet and ki67 were significantly decreased whereas CTGF, HGF, VEGF, IGF showed no significant, indicating that wound healing was not taking place in the chronic tendons. Likewise the inflammatory factors COX-1, IL-1 and IL-6 showed no significant changes. The density and Mean area of collagen fibrils were significant different with the tendinopathic part of the tendons showing significant more fibrils per uM2 with a small diameter and mean area.

CONCLUSIONS: In summery several gene expressions changed with tendinopathy indicating an increased collagen turnover in tendinopathy. Further theses changes in gene expression might have promoted the structural changes of the collagen fibrils taking place in tendinopathy. Since no signs of fibrillogenesis, inflammation or wound healing could be detected, these study supports that tendinopathy is an ongoing degenerative process.

701 June 2 10:00 AM - 10:15 AM

Increased Ligament Thickness Occurs in Previously Sprained Ankles

Kathy Liu, Geoff Gustavsen, Thomas W. Kaminski, FACSM. University of Delaware, Newark, DE.

(No relationships reported)

The anterior talofibular ligament (ATFL) is the most susceptible to damage during a lateral ankle sprain (LAS). Following a LAS, the fibrous structure of a ligament can be disrupted by scar tissue formation. Although the strength of ligaments can be sufficient for active movement and injury rehabilitation soon after injury, the presence of scar tissue within the structure is enough to decrease the load capacity and alter its’ stabilizing properties.

PURPOSE: To determine if differences in ligament thickness exist between healthy and previously sprained ankles.

METHODS: Seventeen Division-I collegiate athletes (11 females, 6 males, age= 18.5 ± 0.5 yrs., height= 175.6 ± 12.1 cm, mass= 75.5 ± 21.2 kg) with a history of unilateral ankle sprains participated in this study. Each participant reported the number of sprains for each ankle. Measurements for thickness of the ATFL were obtained using musculoskeletal ultrasound (MSUS). Using ultrasonic sound waves, the MSUS provides an image of the ATFL and a built-in measuring tool quantifies the thickness of the ligament. Thickness was measured at the midpoint of the ligament between the attachments on the lateral malleolus and talus. Measurements were taken from each ankle. A within subject paired t-test was conducted comparing thickness measures from the healthy ankle to the previously sprained ankle. Statistical significance was set at p < 0.05.

RESULTS: The number of previous ankle sprains ranged from 1 to 3. Thickness of the ATFL ranged from 1.6 mm to 3.3 mm. There was a significant difference (p=0.003) in ATFL thickness of healthy ankles (2.1 mm ± 0.4 mm) compared to previously sprained ankles (2.4 mm ± 0.5 mm). The previously sprained ankles had a significantly thicker ligament than the healthy ankles that have never been sprained.

CONCLUSION: Damage to the ATFL resulting from the scar tissue formation decreases the ability of the ligament to withstand high loads; this decreased load capacity weakens the ligament. Clinicians should pay close attention to interventions that lessen the uncontrolled scar tissue formation. Interventions that have previously been employed to assist with limiting scar tissue formation have included cross friction massage, therapeutic ultrasound, and laser therapy, to name a few.

702 June 2 10:15 AM - 10:30 AM

Changes in Long Head of the Biceps Tendon Size Following an Extended Pitching Performance

David W. Keeley1, Gretchen D. Oliver2, Christopher P. Dougherty3, Michael R. Torry4. 1New Mexico State University, Las Cruces, NM. 2University of Arkansas, Fayetteville, AR. 3Agility Center Orthopedics, Bentonville, AR. 4Illinois State University, Normal, IL.

(No relationships reported)

High biceps loads during the deceleration phase of baseball pitching may predispose one to injury to the long head of the biceps tendon (LHBT).

PURPOSE: To examine changes in length, width, and longitudinal axis width of the LHBT tendon following extended pitching.

METHODS: Twenty pitchers (12.5 ± 2.1 years; 151.2 ± 11 cm; 46.7 ± 11.4 kg) participated in a simulated competitive performance. Upon reaching a pitch count of 85 pitches, pitchers were allowed to complete the situation that was currently in-progress as per little league rules. Data describing width, depth, and longitudinal axis width of the LHBT were collected at the onset and conclusion of the simulated game via diagnostic ultrasound using a 7-12 MHz linear transducer probe. To test for differences in LHBT measurements collected prior to and following the conclusion of the simulated game, pared sample t-tests were conducted with alpha set at α = 0.017.

RESULTS: Results of mean difference testing revealed that with the throwing arm in the neutral position both LHBT intra-groove width and depth differed significantly across the pitching performance. With the throwing arm abducted to 90° only LHBT intra-groove depth differed at the conclusion of the performance.

CONCLUSION: The underlying exact cause of the observed tendon hypertrophy observed in this study is unknown. Although it and may be advantageous with regard to decreasing the stress transmitted across the LHBT during pitching, it may ultimately function to increase the likelihood of baseball pitchers developing common shoulder pathologies. These pathologies include tendonitis of the LHBT resulting from microscopic trauma and increased degredation of the biceps refection pulley though increased contact with the LHBT tendon.

703 June 2 10:30 AM - 10:45 AM

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Heated Lidocaine/tetracaine Topical Patch For Treatment Of Painful Patellar Tendinopathy: An Open-label Study

Henry Goitz1, Thomas Marriott2. 1Detroit Medical Center Sports Medicine, Warren, MI. 2ZARS Pharma, Inc., Salt Lake City, UT.

( H. Goitz: Salary; ZARS Pharma, Inc.. Ownership Interest; ZARS Pharma, Inc..)

PURPOSE: To explore the potential usefulness of a heated lidocaine/tetracaine topical patch for the treatment of pain associated with patellar tendinopathy.

METHODS: This was a 2-week, open-label, outpatient study in 13 adult patients with a ≥2-week history of tenderness at the proximal insertion of the patellar tendon to the patella and average pain intensity over the last 24 h of ≥4 on an 11-point scale (0, no pain, to 10, pain as bad as you can imagine). Patients applied 1 heated lidocaine/tetracaine topical patch directly to the affected patellar tendon at the site of maximal tenderness for 2-4 h twice daily for 14 consecutive days. No analgesics were allowed except for acetaminophen for minor conditions or for acute episodes of pain associated with patellar tendinopathy. Use of acetaminophen for 2 consecutive days for patellar tendinopathy constituted treatment failure. Outcome measures were pain intensity (average pain over the last 24 h), recorded each evening on Days 1-14; overall symptom severity, assessed at baseline and on Day 14 by the Victorian Institute of Sport Assessment (VISA) scale total score (0 to 100, where 100 represents an asymptomatic, fully performing individual); and patient global assessment of treatment satisfaction (5-point scale; 0, very dissatisfied to 4, very satisfied).

RESULTS: All 13 patients completed the study and none discontinued due to treatment failure or AEs. Pain was reduced and overall symptom severity was improved after treatment with the patch. The mean (SD) average pain intensity at baseline was 5.5 (1.3) and on Day 14 was 3.7 (2.5), representing a mean 32% (46%) reduction from average baseline pain intensity. The mean (SD) VISA total score at baseline was 39 (13) and on Day 14 was 49 (19), representing a mean 27% (30%) improvement over baseline symptom severity. Most patients (8 of 13) were satisfied or very satisfied with treatment. Treatment-related AEs were mild and included application site erythema (3 pts), application site dryness (1), and headache (1).

CONCLUSION: Application of a heated lidocaine/tetracaine topical patch was well tolerated and produced clinically meaningful reductions in pain intensity and improvement of symptoms in patients with patellar tendinopathy.

704 June 2 10:45 AM - 11:00 AM

Type 2, But Not Type 1 Diabetes, Predisposes To Achilles Tendon Disintegration

Suzan de Jonge1, Robert Rozenberg1, Bruno Vieyra1, Henk J. Stam1, Henk-Jan Aanstoot2, Harrie Weinans1, Hans T.M. van Schie1, Stephan F.E. Praet1. 1Erasmus MC, Rotterdam, Netherlands. 2Diabeter Center for Pediatric and Adolescent Diabetes Care and -Research, Rotterdam, Netherlands.

(No relationships reported)

Tendinomuscular overuse injury is a frequent cause for premature termination of exercise programs in Diabetes Mellitus (DM) type 2. The pathomechanism behind tendon degeneration in DM is largely unknown. Glycation of tendon collagen may play a role. The extent of glycation is reflected in the formation of advanced glycation endproducts (AGEs) which can be measured through skin autofluorescence. [1]

PURPOSE: To determine whether AGEs in skin are related to advanced disintegration of Achilles tendons in patients with DM.

METHODS: In DM patients and controls (matched for gender and age), computerized Ultrasonographic Tissue Characterization (UTC) was performed of both Achilles tendons. In contiguous ultrasonographic images, dedicated algorithms quantified 3D-stabilitiy of echo-patterns. ] As such four echo-types were discriminated: I) intact and aligned tendon bundles; II) discontinuous or waving tendon bundles; III) fibrillar components; IV) mainly cellular components and fluid in amorphous tissue. Tendon disintegration was quantified as sum of echo-types III + IV. The AGE-value (AU: arbitrary units) was measured using a skin-autofluorescence test of the forearm.

RESULTS: Twenty six patients with DM2 (mean age 50.2±8.4 yr), 22 controls (47.2±6.0), 16 patients with DM1 (23.9±2.8) and 20 age-matched controls (24.2±2.7) were included in the study. The Achilles tendons of patients with DM2 showed more echo-types III+IV than their controls (resp. 13.6%±7.8 versus 8.6%±5.9, p=0.016). There was no significant difference between DM1 patients (9.2%±5.7) and their controls (7.7%±5.2), p=0.425). The AGE-value was higher in both DM groups (DM1; 1.55±0.17, DM2; 2.28±0.38) compared to the controls (resp. 1.39±0.18 and 1.84±0.32) both p<0.001). No significant correlation was found between the AGE score in forearm skin and proportion of disorganized tendon structure of the Achilles tendon (R=0.211, p=0.059).

CONCLUSION: DM2 patients have more structural abnormalities of the Achilles tendon tissue and show elevated AGE scores. However, a relation between AGE score and tendon abnormalities in DM was not found.

Funding: Dutch Diabetes Research Foundation grant#2010.11.1387

1. Gerrits, E.G., et al., Diabetes Care, 2008. 31(3): p. 517-21.

2. van Schie, H.T., et al., Br J Sports Med, 2010. 44(16): p. 1153-9.

©2012The American College of Sports Medicine

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