Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise

There is evidence that protein hydrolysates can speed tissue repair following damage and may therefore be useful for accelerating recovery from exercise induced muscle damage. The potential for a hydrolysate (WPI(HD)) of whey protein isolate (WPI) to speed recovery following eccentric exercise was evaluated by assessing effects on recovery of peak isometric torque (PIT). In a double-blind randomised parallel trial, 28 sedentary males had muscle soreness (MS), serum creatine kinase (CK) activity, plasma TNF alpha, and PIT assessed at baseline and after 100 maximal eccentric contractions (ECC) of their knee extensors. Participants then consumed 250 ml of flavoured water (FW; n = 11), or FW containing 25 g WPI (it = 11) or 25 g WPI(HD)) (n = 6) and the assessments were repeated 1, 2 6 and 24 h later. PIT decreased similar to 23% following ECC, remained suppressed in FW and WPI, but recovered fully in WPI(HD) by 6h (P=0.006, treatment x time interaction). MS increased following ECC (P<0.001 for time), and remained elevated with no difference between groups (P=0.61). TNF alpha and CK did not change (P>0.45). WPI(HD) may be a useful supplement for assisting athletes to recover from fatiguing eccentric exercise. (C) 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.