Lactotripeptides Supplementations Alleviate the Decrease in Maximal Isometric Force after High-Intensity Eccentric Exercise: A Randomized, Placebo-Controlled, Double-Blind Clinical Trial

Objective The aim of the study was to investigate whether lactotripeptides supplementations alleviate the decrease in the maximal isometric force, an indirect marker of muscle damage, after eccentric exercise (ECC). Design Twenty-two young men performed 50 ECC of the elbow flexors using an isokinetic dynamometer. The subjects were randomly assigned to either the placebo or lactotripeptides group and were each given a 4.5 mg/d placebo or lactotripeptides thrice on the exercise day and the day after. Maximal isometric force and brachial arterial diameter were assessed before and 2 days after the ECC. Results The interaction of time and group on maximal isometric force was significant (P < 0.05); maximal isometric force was significantly decreased in both groups after ECC (P < 0.005). The interaction of brachial arterial diameter was significant (P < 0.05); brachial arterial diameter was significantly increased in only the lactotripeptides group (P < 0.005). In addition, the change in maximal isometric force was significantly related to the change in brachial arterial diameter after adjusting for body weight and change in range of motion (P < 0.05). Conclusions The present results suggest that lactotripeptides supplementation alleviates the decrease in the maximal isometric force via an increase in brachial arterial diameter after ECC.