Summary: | <p>Abstract</p> <p>Background</p> <p>This study examined the effect of carbohydrate and whey protein supplements on recovery of neuromuscular function after prolonged load carriage.</p> <p>Methods</p> <p>Ten male participants (body mass: 81.5 ± 10.5 kg, age: 28 ± 9 years, <inline-formula><graphic file="1550-2783-7-2-i1.gif"/></inline-formula> O<sub>2</sub>max: 55.0 ± 5.5 ml·kg<sup>-1</sup>·min<sup>-1</sup>) completed three treadmill walking tests (2 hr, 6.5 km·h<sup>-1</sup>), 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.</p> <p>Results</p> <p>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 (<it>P </it>= 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<sup>-1</sup>) recovered to pre-exercise values at 72 h. Trunk extensor and flexor peak torque (15°·s<sup>-1</sup>) recovered to pre-exercise values at 24 h (<it>P </it>= 0.091) and 48 h (<it>P </it>= 0.177), respectively.</p> <p>Conclusion</p> <p>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.</p>
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