BCAAs for reducing exercise-induced muscle damage and soreness in trained young men Original paper

Evidence from meta-analyses of clinical trials suggests that supplementation with branched chain amino acids (BCAAs) may have beneficial effects on exercise-induced muscle soreness and markers of muscle damage. However, the broad eligibility criteria of these meta-analyses in terms of the training status, age, and sex of the participants and the type of exercise performed limit the generalizability of the results.

This meta-analysis of 9 randomized controlled trials examined the effects of supplementation with BCAAs alone, compared to a nonprotein placebo or no intervention, on markers of muscle damage after resistance exercise in 278 trained young men (ages 18–25).

Of the 9 trials, 7 used a parallel design, and 2 used a crossover design. The period of BCAA supplementation ranged from 1 to 28 days using the following strategies: preload only (2 trials), on the exercise day only (3 trials), preload on the exercise day (1 trial), on the exercise day and during the recovery period (1 trial), and preload on the exercise day and during the recovery period (2 trials).

Muscle damage was measured using the levels of plasma lactate dehydrogenase (2 trials) and creatine kinase (6 trials), and 5 trials measured muscle soreness using a visual analogue scale. These outcomes were assessed <24 to 96 hours after exercise.

BCAA supplementation reduced creatine kinase levels (indicating reduced muscle damage) at <24, 24, and 48 hours after exercise and improved muscle soreness at <24 hours only. However, the observed effects were small.

All trials were assessed as having a low risk of bias.