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

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

Trent A. Hargens, FACSM, Lindsay J. Lickers, Amanda J. Becker, Christopher J. Womack, FACSM, Nicholas D. Luden. James Madison University, Harrisonburg, VA. Adequate sleep is a vital component of health and wellness. Poor sleep has been shown to significantly impact athletic performance; however most research has focused on several days or more of sleep deprivation. The impact of a single night of sleep restriction on subsequent performance is less well understood. This paradigm would more closely mimic anxiety and nervousness prior to an important event. PURPOSE: To examine the effect of one night of sleep restriction (SR) on cycle time trial (TT) performance compared to a night of normal sleep (NS). METHODS: Eight recreational cyclists [age = 20.6 ± 1.4 yr; body mass index (BMI) = 23.0 ± 1.9; VO2max = 42.7 ± 6.6 mL/kg/min/] completed 3 performance trials (1 familiarization and 2 experimental) on a cycle ergometer. Performance trials consisted of a 3-kilometer TT. Experimental trials were performed after NS (6-8 hours) or SR (3 hours). Order of experimental trials was randomized. Experimental trials were performed at the same time of day (6:00 - 8:00 am). 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. RESULTS: There was no difference in average power (151 ± 32 vs. 146 ± 41 Watts for SR and NS, respectively; P = 0.3), peak power (230 ± 66 vs. 239 ± 89 Watts; P = 0.6) or average heart rate (187 ± 11 vs. 189 ± 15; P = 0.5) between the experimental trials. Additionally, there was no significant difference in TT finish time (6.0 ± 0.5 vs. 6.2 ± 0.8 sec for SR and NS, respectively; P = 0.5) despite a 10.5 second faster time with SR. 5 of 8 subjects has a faster finishing time with the SR trial. CONCLUSION: Results showed no difference in TT finishing time between the SR and NS conditions, yet a majority of subjects performed better during the SR condition. Additional research with a greater sample is needed to further assess this question. A potential mechanism for the faster time with SR may be sleep inertia, which is the transitional state between sleep and wake, characterized by impaired performance. Sleep inertia can last for several hours. In the current study, subjects completed the TT in the NS condition within the time frame where sleep inertia could affect performance

DIETARY NITRATE SUPPLEMENTATION ENHANCES HEAVY LOAD CARRIAGE PERFORMANCE IN MILITARY CADETS

Nicholas Cole Bordonie1, Michael J. Saunders, FACSM2, Joaquin Ortiz de Zevallos3, Stephanie P. Kurti2, Nicholas D. Luden2, Jenny H. Crance4, Daniel A. Baur4. 1Auburn University, Auburn, AL. 2James Madison University, Harrisonburg, VA. 3University of Virginia, Charlottsville, VA. 4Virginia Military Institute, Lexington, VA. BACKGROUND: Soldiers are commonly required to carry heavy loads (\u3e 35 kg) that increase metabolic rates and exercise intensity, which can negatively impact performance. The purpose of this study was to determine the effects of dietary nitrate (NO3−) supplementation on physiological responses, cognitive function, and performance during heavy load carriage in military cadets. METHODS: Ten healthy males (81.0 ± 6.5 kg; 180.0 ± 4.5 cm; 56.2 ± 3.7 ml·kg·min-1 VO2max) consumed 140 mL·d-1 of beetroot juice (BRJ; 12.8 mmol NO3−) or placebo (PL) for six days preceding an exercise trial consisting of 45 min of load carriage (55% body mass) at 4.83 km·h-1 and 1.5% grade, followed by a 1.6-km time-trial (TT) at 4% grade. Gas exchange, heart rate, and perceptual responses were assessed at during constant-load exercise and the TT. Cognitive function was assessed immediately prior to, during, and post-exercise via the psychomotor vigilance test. RESULTS: There were no effects of BRJ on constant-load gas exchange or perceptual responses, and cognitive function was unchanged at all time points. However, there were small effect sizes (Cohen’s d) for response times and lapses, respectively, during-exercise (PL vs. BRJ: +15.2 ms and +2.3; d = 0.26 and 0.28) and in the change from rest to exercise (PL vs. BRJ: +18.2 ms and +3.2; d = 0.49 and 0.48). Additionally, post-TT HR (188 ± 7.1 vs. 185 ± 7.4; d = 0.40; p =0.03), mean tidal volume (2.15 ± 0.27 vs. 2.04 ± 0.23; p = 0.02; d = 0.47), and performance over 1.6 km (770.9 ± 78.2 s vs. 809.8 ± 61.4 s; p = 0.03; d = 0.63) were increased/enhanced during the TT with BRJ versus PL. CONCLUSIONS: BRJ supplementation improves heavy load carriage performance in military cadets possibly as a result of attenuated respiratory muscle fatigue, rather than enhanced exercise economy

In vivo specific tension of the human quadriceps femoris muscle.

It is not known to what extent the inter-individual variation in human muscle strength is explicable by differences in specific tension. To investigate this, a comprehensive approach was used to determine in vivo specific tension of the quadriceps femoris (QF) muscle (Method 1). Since this is a protracted technique, a simpler procedure was also developed to accurately estimate QF specific tension (Method 2). Method 1 comprised calculating patellar tendon force (F (t)) in 27 young, untrained males, by correcting maximum voluntary contraction (MVC) for antagonist co-activation, voluntary activation and moment arm length. For each component muscle, the physiological cross-sectional area (PCSA) was calculated as volume divided by fascicle length during MVC. Dividing F (t) by the sum of the four PCSAs (each multiplied by the cosine of its pennation angle during MVC) provided QF specific tension. Method 2 was a simplification of Method 1, where QF specific tension was estimated from a single anatomical CSA and vastus lateralis muscle geometry. Using Method 1, the variability in MVC (18%) and specific tension (16%) was similar. Specific tension from Method 1 (30 +/- 5 N cm(-2)) was similar to and correlated with that of Method 2 (29 +/- 5 N cm(-2); R (2) = 0.67; P < 0.05). In conclusion, most of the inter-individual variability in MVC torque remains largely unexplained. Furthermore, a simple method of estimating QF specific tension provided similar values to the comprehensive approach, thereby enabling accurate estimations of QF specific tension where time and resources are limited

Recovery in Soccer

International audienceIn the formerly published part I of this two-part review, we examined fatigue after soccer matchplay and recovery kinetics of physical performance, and cognitive, subjective and biological markers. To reduce the magnitude of fatigue and to accelerate the time to fully recover after completion, several recovery strategies are now used in professional soccer teams. During congested fixture schedules, recovery strategies are highly required to alleviate post-match fatigue, and then to regain performance faster and reduce the risk of injury. Fatigue following competition is multifactorial and mainly related to dehydration , glycogen depletion, muscle damage and mental fatigue. Recovery strategies should consequently be targeted against the major causes of fatigue. Strategies reviewed in part II of this article were nutritional intake, cold water immersion, sleeping, active recovery, stretching , compression garments, massage and electrical stimulation. Some strategies such as hydration, diet and sleep are effective in their ability to counteract the fatigue mechanisms. Providing milk drinks to players at the end of competition and a meal containing high-glycaemic index carbohydrate and protein within the hour following the match are effective in replenishing substrate stores and optimizing muscle-damage repair. Sleep is an essential part of recovery management. Sleep disturbance after a match is common and can negatively impact on the recovery process. Cold water immersion is effective during acute periods of match congestion in order to regain performance levels faster and repress the acute inflammatory process. Scientific evidence for other strategies reviewed in their ability to accelerate the return to the initial level of performance is still lacking. These include active recovery, stretching, compression garments, massage and electrical stimulation. While this does not mean that these strategies do not aid the recovery process, the protocols implemented up until now do not significantly accelerate the return to initial levels of performance in comparison with a control condition. In conclusion, scientific evidence to support the use of strategies commonly used during recovery is lacking. Additional research is required in this area in order to help practitioners establish an efficient recovery protocol immediately after matchplay, but also for the following days. Future studies could focus on the chronic effects of recovery strategies, on combinations of recovery protocols and on the effects of recovery strategies inducing an anti-inflammatory or a pro-inflammatory response