Research article

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

Sam D Blacker¹ , Neil C Williams¹ , Joanne L Fallowfield² , James LJ Bilzon³ and Mark ET Willems¹

¹  University of Chichester, Faculty of Sport, Education and Social Sciences, West Sussex, UK

²  Institute of Naval Medicine, Gosport, Hampshire, UK

³  University of Bath, School for Health, Bath, UK

author email corresponding author email

Journal of the International Society of Sports Nutrition 2010, 7:2doi:10.1186/1550-2783-7-2

Published:	12 January 2010

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, O₂max: 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°·s^-1) recovered to pre-exercise values at 72 h. Trunk extensor and flexor peak torque (15°·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.