Dataset Information

Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage.

ABSTRACT:

Background

This study examined the effect of carbohydrate and whey protein supplements on recovery of neuromuscular function after prolonged load carriage.

Methods

TEN MALE PARTICIPANTS (BODY MASS: 81.5 +/- 10.5 kg, age: 28 +/- 9 years, O(2)max: 55.0 +/- 5.5 ml.kg(-1).min(-1)) completed three treadmill walking tests (2 hr, 6.5 km.h(-1)), carrying a 25 kg backpack consuming 500 ml of either: (1) Placebo (flavoured water) [PLA], (2) 6.4% Carbohydrate Solution [CHO] or (3) 7.0% Whey Protein Solution [PRO]. For three days after load carriage, participants consumed two 500 ml supplement boluses. Muscle performance was measured before and at 0, 24, 48 and 72 h after load carriage, during voluntary and electrically stimulated contractions.

Results

Isometric knee extension force decreased immediately after load carriage with no difference between conditions. During recovery, isometric force returned to pre-exercise values at 48 h for CHO and PRO but at 72 h for PLA. Voluntary activation decreased immediately after load carriage and returned to pre-exercise values at 24 h in all conditions (P = 0.086). During recovery, there were no differences between conditions for the change in isokinetic peak torque. Following reductions immediately after load carriage, knee extensor and flexor peak torque (60 degrees .s(-1)) recovered to pre-exercise values at 72 h. Trunk extensor and flexor peak torque (15 degrees .s(-1)) recovered to pre-exercise values at 24 h (P = 0.091) and 48 h (P = 0.177), respectively.

Conclusion

Recovery of neuromuscular function after prolonged load carriage is improved with either carbohydrate or whey protein supplementation for isometric contractions but not for isokinetic contractions.

SUBMITTER: Blacker SD

PROVIDER: S-EPMC2821364 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage.

Blacker Sam D SD Williams Neil C NC Fallowfield Joanne L JL Bilzon James Lj JLj Willems Mark Et ME

Journal of the International Society of Sports Nutrition 20100112

<h4>Background</h4>This study examined the effect of carbohydrate and whey protein supplements on recovery of neuromuscular function after prolonged load carriage.<h4>Methods</h4>TEN MALE PARTICIPANTS (BODY MASS: 81.5 +/- 10.5 kg, age: 28 +/- 9 years, O(2)max: 55.0 +/- 5.5 ml.kg(-1).min(-1)) completed three treadmill walking tests (2 hr, 6.5 km.h(-1)), carrying a 25 kg backpack consuming 500 ml of either: (1) Placebo (flavoured water) [PLA], (2) 6.4% Carbohydrate Solution [CHO] or (3) 7.0% Whey ...[more]

PMID: 20157419

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Project description:UnlabelledTrekking and military missions generally consist of carrying heavy loads for extreme durations. These factors have been separately shown to be sources of neuromuscular (NM) fatigue and locomotor alterations. However, the question of their combined effects remains unresolved, and addressing this issue required a representative context.PurposeThe aim was to investigate the effects of extreme-duration heavy load carriage on NM function and walking characteristics.MethodsTen experienced infantrymen performed a 21-h simulated military mission (SMM) in a middle-mountain environment with equipment weighing ∼27 kg during battles and ∼43 kg during marches. NM function was evaluated for knee extensors (KE) and plantar flexors (PF) pre- and immediately post-SMM using isometric maximal voluntary contraction (MVC) measurement, neural electrical stimulation and surface EMG. The twitch-interpolation method was used to assess central fatigue. Peripheral changes were examined by stimulating the muscle in the relaxed state. The energy cost, mechanical work and spatio-temporal pattern of walking were also evaluated pre-/post-SMM on an instrumented treadmill in three equipment conditions: Sportswear, Battle and March.ResultsAfter the SMM, MVC declined by -10.2±3.6% for KE (P<0.01) and -10.7±16.1% for PF (P = 0.06). The origin of fatigue was essentially peripheral for both muscle groups. A trend toward low-frequency fatigue was detected for KE (5.5%, P = 0.08). These moderate NM alterations were concomitant with a large increase in perceived fatigue from pre- (rating of 8.3±2.2) to post-SMM (15.9±2.1, P<0.01). The SMM-related fatigue did not alter walking energetics or mechanics, and the different equipment carried on the treadmill did not interact with this fatigue either.Conclusionthis study reports the first data on physiological and biomechanical consequences of extreme-duration heavy load carriage. Unexpectedly, NM function alterations due to the 21-h SMM were moderate and did not alter walking characteristics.Clinical trial registrationName: Effect of prolonged military exercises with high load carriage on neuromuscular fatigue and physiological/biomechanical responses. Number: NCT01127191.

Project description:Objectives: The objective of this study was to assess if injury-related alterations in the Sport Concussion Assessment Tool-5 (SCAT5) are matched by changes in transcranial magnetic stimulation-derived intracortical inhibition. We hypothesised that neurophysiological measures would take longer to return to normal than recovery assessed by the SCAT5 following sport related concussion (SRC). Methods: Thirteen male contact sport athletes (20.5 ± 4.5 years), who reported a concussion were recruited from local Rugby and American football clubs. Participants were tested at 4 timepoints throughout the concussion recovery period: within 24 h of concussion (day 0), and at 7, 9, and 11 days after concussion. All participants completed the SCAT5 and underwent TMS to assess cortical silent period duration (CSp), a measure of intracortical inhibition. Results: After concussion CSp significantly declined from day 0 (122 ± 28 ms) to day 11 (106 ± 15 ms) [F (3, 33) = 7.80, p < 0.001]. SCAT5 measures of symptom number and severity were significantly decreased [symptom number: χ(3)2 = 30.44, p < 0.01; symptom severity: χ(3)2 = 25.75, p < 0.001] between the day 0 timepoint and each of the other timepoints. SCAT5 balance errors (mBESS) decreased significantly [F (3, 33) = 19.55, p < 0.001] between the day 0 timepoint and each of the other timepoints. CSp and SCAT5 recovery patterns were different. SCAT5 domains recovered faster showing no further significant changes after day 7, whilst CSp was still decreasing between days 7 and 9. Due to the small sample size we also used a Bayesian linear model to investigate the recovery of CSp and mBESS. The posterior distribution of our Bayesian model provided evidence that CSp decreased at day 7 and it continued to decrease at day 9, unlike mBESS which decreased at day 7 and then reached a plateau. Conclusion: There are clinically important discrepancies between clinical and neurophysiological measures of concussion recovery. This finding has important implications for return to play (RTP) protocols and the prevention of complications after sport concussion.

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Dataset Information

Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage.

Background

Methods

Results

Conclusion

Publications

Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage.

Similar Datasets

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