The effect of branched-chain amino acid on muscle damage markers and performance following strenuous exercise: a systematic review and meta-analysis.

This systematic review and meta-analysis determined whether the ergogenic effects of branched-chain amino acids (BCAA) ameliorated markers of muscle damage and performance following strenuous exercise. In total, 25 studies were included, consisting of 479 participants (age 24.3 ± 8.3 years, height 1.73 ± 0.06 m, body mass 70.8 ± 9.5 kg, females 26.3%). These studies were rated as fair to excellent following the PEDro scale. The outcome measures were compared between the BCAA and placebo conditions at 24 and 48 hours following muscle-damaging exercises, using standardised mean differences and associated p-values via forest plots. Our meta-analysis demonstrated significantly lower levels of indirect muscle damage markers (creatine kinase, lactate dehydrogenase and myoglobin) at 48 hours post-exercise (standardised mean difference [SMD] = -0.41; p < 0.05) for the BCAA than placebo conditions, whilst muscle soreness was significant at 24 hours post-exercise (SMD = -0.28 ≤ d ≤ -0.61; p < 0.05) and 48 hours post-exercise (SMD = -0.41 ≤ d≤ -0.92; p < 0.01). However, no significant differences were identified between the BCAA and placebo conditions for muscle performance at 24 or 48 hours post-exercise (SMD = 0.08 ≤ d ≤ 0.21; p > 0.05). Overall, BCAA reduced the level of muscle damage biomarkers and muscle soreness following muscle-damaging exercises. However, the potential benefits of BCAA for muscle performance recovery is questionable and warrants further investigation to determine the practicality of BCAA for ameliorating muscle damage symptoms in diverse populations. PROSPERO registration number: CRD42020191248. Novelty: BCAA reduces the level of creatine kinase and muscle soreness following strenuous exercise with a dose-response relationship. BCAA does not accelerate recovery for muscle performance.

The effect of leaf extract supplementation on exercise-induced muscle damage and muscular performance: A systematic review and meta-analysis.

This systematic review and meta-analysis investigated the effects of leaf-plant extracts typically used for tea beverages on the level of exercise-induced muscle damage. The meta-analysis was conducted by comparing measures between the leaf-extract supplements (SUPP) and placebo (PLA) conditions at 24 h and 48 h following the muscle-damaging protocols from 19 studies with 416 participants. The results showed that the SUPP condition exhibited significantly lower indirect muscle damage markers than the PLA condition at 24- and 48-h post-exercise (p < 0.05). Furthermore, oxidative stress markers were significantly lower for the SUPP condition than the PLA condition at 24-h post-exercise (p < 0.05), although not at 48-h post-exercise (p > 0.05). In addition, no differences were found for anti-oxidant status at 24- and 48-h post-exercise (p > 0.05) between conditions. Muscle performance measures significantly increased for the SUPP condition than the PLA condition at 24-h post-exercise (p < 0.05), but not at 48-h post-exercise (p > 0.05). These results demonstrate that leaf plant extracts reduces the level of various biomarkers indicative of exercise-induced stress, although its effect on anti-oxidant status remains equivocal. Nonetheless, leaf-plant extracts typically ingested as a tea beverage may be an effective recovery strategy following strenuous exercises.