No effect of short-term amino acid supplementation on variables related to skeletal muscle damage in 100 km ultra-runners - a randomized controlled trial

Background: The purpose of this study was to investigate the effect of short-term supplementation of amino acids before and during a 100 km ultra-marathon on variables of skeletal muscle damage and muscle soreness. We hypothesized that the supplementation of amino acids before and during an ultra-marathon would lead to a reduction in the variables of skeletal muscle damage, a decrease in muscle soreness and an improved performance. Methods: Twenty-eight experienced male ultra-runners were divided into two groups, one with amino acid supplementation and the other as a control group. The amino acid group was supplemented a total of 52.5 g of an amino acid concentrate before and during the 100 km ultra-marathon. Pre- and post-race, creatine kinase, urea and myoglobin were determined. At the same time, the athletes were asked for subjective feelings of muscle soreness. Results: Race time was not different between the groups when controlled for personal best time in a 100 km ultra-marathon. The increases in creatine kinase, urea and myoglobin were not different in both groups. Subjective feelings of skeletal muscle soreness were not different between the groups. Conclusions: We concluded that short-term supplementation of amino acids before and during a 100 km ultra-marathon had no effect on variables of skeletal muscle damage and muscle soreness

THE EFFECT OF ONE NIGHT OF SLEEP FRAGMENTATION ON SUBSEQUENT AEROBIC PERFORMANCE

Trent A. Hargens, FACSM, Tara L. Thompson, Nicki Stallings, Nicholas D. Luden. James Madison University, Harrisonburg, VA. Sleep is a vital component of health and wellness. Poor sleep has been shown to significantly impact athletic performance. Most research, however, has focused on several days or more of sleep deprivation. Sleep fragmentation is defined as multiple arousals during the night, which may impact an athlete before an important event due to pre-competition anxiety. PURPOSE: To examine the effect of one night of sleep fragmentation (SF) on cycle time trial (TT) performance compared to a night of normal sleep (NS). METHODS: Eight active individuals [age = 20.4 ± 1.7 yr.; body mass index (BMI) = 22.0 ± 2.1; VO2max = 41.1 ± 9.8 mL.kg-1.min-1] completed 3 performance trials (1 familiarization and 2 experimental) consisting of a 3-kilometer time trial (TT) on a cycle ergometer. Trials were performed after NS (6-8 hours) or SF. The SF condition consisted of being awakened at least one time per hour of sleep for 8 hours. The trials were performed at the same time of day (8:00 - 10:00 am), with randomly counter-balances sleep conditions. Diet was replicated prior to each trial and physical activity was monitored for 48 hours prior to each trial with accelerometer. Sleep was monitored via accelerometry the night of the experimental trials to confirm sleep duration. Data are presented as means ± SD. RESULTS: There was no difference in peak power (294 ± 107 vs. 306 ± 123 Watts for SF and NS, respectively; P = 0.7), average heart rate (162 ± 16 vs. 168 beats.min-1 ± 12; P = 0.5), or TT finish time (5.6 ± 1.0 vs. 5.5 ± 1.0 minutes; P = 0.1) between the experimental trials. Average TT power trended towards significance (211 ± 83 vs. 228 ± 100 Watts for SF and NS, respectively; P = 0.08). Peak TT oxygen consumption was lower during the SF trial (43.6 ± 12.3 mL.kg-1.min-1) compared to the NS trial (47.9 ± 11.5 mL.kg-1.min-1; P = 0.017), while average oxygen consumption trended lower during the SF trial (37.0 ± 11.5 mL.kg-1.min-1) compared to NS (44.6 ± 14.2 mL.kg-1.min-1, P = 0.07). CONCLUSION: Results showed that SF may impact subsequent 3-km TT performance, reflected by a lower peak VO2 and a trend towards lower average power output and oxygen consumption, although there were no differences in TT finish time. Further research with a larger sample size is needed to make more definitive conclusions about the potential consequences of SF

EFFECTS OF TRAINING AND SEX ON EXPIRATORY FLOW LIMITATION PREVALENCE AND SEVERITY IN YOUTH CYCLISTS

Will Burton1, Sarah Ridgeway1, Katherine Cox1, Joshua Smith2, Nicholas Luden1, Michael Saunders, FACSM1, Stephanie Kurti1. 1Human Performance Laboratory, James Madison University, Harrisonburg, VA. 2Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN. BACKGROUND: Expiratory flow limitation (EFL) poses a potential mechanical limitation of the pulmonary system during maximal exercise in endurance-trained athletes, but the prevalence in females and males of pubertal age is not well understood. The purpose of this investigation was to assess EFL presence in endurance-trained (ET) youth males and females compared to a recreationally active (RA) control group. METHODS: Youth ET male (n=12, 16.3 ± 1.0 y), RA male (n=12, 17.6 ± 2.2 y), ET female (n=9, 15.8 ± 1.1 y), and RA female (n=10, 16.8 ± 1.6 y) subjects completed an incremental exercise test to exhaustion on a cycle ergometer to determine peak oxygen consumption (VO2peak). Maximal flow volume loops (MFVL) were performed pre- and post-exercise to assess forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC, forced expiratory flow between 25% and 75% of FVC (FEF25-75% of FVC) and peak expiratory flow (PEF). Inspiratory capacity (IC) maneuvers were performed the last 20 seconds of every stage. EFL was quantified as the percentage of the expiratory tidal volume that overlapped with the MFVL. RESULTS: EFL prevalence was higher in ET males and females at VO2peak (18/21 subjects; 11/12 males, 7/9 females) compared to RA male and female subjects (7/22 subjects; 5/12 males, 2/10 females) (p \u3c 0.05). ET females had significantly greater EFL severity than RA females at maximal exercise (57.0 ± 36.4%, 13.3 ± 32.2%, respectively, p = 0.013), while there was no difference in EFL severity between ET and RA males (p = 0.473). ET males also had significantly greater EFL severity at maximal exercise compared to RA males (75.0 ± 32.9%, 29.7 ± 40.4%, p = 0.007). There was no difference in the prevalence and severity of flow-limitation between ET males and females or between RA males and females (p’s \u3e 0.05). CONCLUSIONS: Both ET male and ET female cyclists demonstrated greater prevalence and severity of EFL at maximal exercise than respective same-sex RA subjects of similar age, height, and lung size. Further research should be conducted to determine whether EFL may limit exercise performance in this population and whether EFL exists into adulthood