Objective: Accumulating evidence suggests positive effects of branched-chain amino acids (BCAAs) on moderate muscle damage. However, findings vary substantially across studies. The aim of this review was to examine the effect of BCAAs on recovery following exercise-induced muscle damage.
Methods: Controlled trials were identified through a computerized literature search and tracking of citations performed up to November 2015. To pool data, either a fixed-effects or a random-effects model was used; for assessing heterogeneity, Cochran's Q and I2 tests were used.
Results: Eight trials met the inclusion criteria. Pooled data from the eight studies showed that BCAAs significantly reduced creatine kinase at two follow-up times (<24 and 24 h) in comparison with placebo recovery (<24 h: mean difference, -71.55 U/L, 95% confidence interval, -93.49 to -49.60, P < 0.000, n = 5 trials; 24 h: mean difference, -145.04 U/L, 95% confidence interval, -253.66 to -36.43, P = 0.009, n = 8 trials). In contrast, effects were not significant in any of the follow-up times for muscle soreness or lactate dehydrogenase.
Conclusion: The current evidence-based information indicates that use of BCAAs is better than passive recovery or rest after various forms of exhaustive and damaging exercise. The advantages relate to a reduction in muscle soreness and ameliorated muscle function because of an attenuation of muscle strength and muscle power loss after exercise.
Keywords: Branch-chain amino acids; Exercise; Meta-analysis; Muscle damage; Muscle soreness.
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