The effects of 8 weeks of heavy resistance training and branched-chain amino acid supplementation on body composition and muscle performance

PURPOSE This study determined the effects of 8 weeks of heavy resistance training combined with branched-chain amino acid (BCAA) supplementation on body composition and muscle performance. METHODS Resistance training was performed by 19 non-resistance-trained males (three sets of 8-10 repetitions) four times/week, for 8 weeks, while also ingesting 9 g/day of BCAA or 9 g/day of placebo (PLAC) on the exercise days only (one-half of total dose 30 min before and after exercise). Data were analyzed with separate 2 × 2 analysis of variance (ANOVA) (p < 0.05). RESULTS For total body mass, neither group significantly increased with training (p = 0.593) and also, there were no significant changes in total body water (p = 0.517). In addition, no training- or supplement-induced (p = 0.783) changes occurred with fat mass or fat-free mass (p = 0.907). Upper-body (p = 0.047) and lower-body strength (p = 0.044) and upper- (p = 0.001) and lower-body muscle endurance (p = 0.013) increased with training; however, these increases were not different between the groups (p > 0.05). CONCLUSION When combined with heavy resistance training for 8 weeks, supplementation with 9 g/day of BCAA 30 min before and after exercise had no preferential effects on body composition and muscle performance.