Riggs, A. J., Mills, A., McMillian, J., Rossi, S., & Joyner, S. (2013). Effect of pre-exercise BCAA supplement with or without carbohydrates on performance in competitive cyclists. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 2417.

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This study determined if ingestion of branched-chain amino acids with or without carbohydrate prior to exercise, improved performance or perceived exertion in competitive cyclists (N = 6) that had not undergone glycogen depletion. On trial days, Ss were asked to report to the laboratory in a fasted state. In a randomized, double-blind, crossover experimental design, Ss received one of three treatments prior to exercising: 1) branched-chain amino acids supplementation; 2) carbohydrate plus branched-chain amino acids supplementation or 3) placebo. Ten minutes following ingestion, Ss performed a cycle time to exhaustion at 80% VO2max, during which heart rate was recorded continuously and ratings of perceived exertion were measured every three minutes. A washout period of one week was used between trials.

Cycling time to exhaustion and ratings of perceived exertion were not significantly different between trials.

Implication. The ingestion of branched-chain amino acids, with or without carbohydrate, prior to high-intensity exercise does not improve performance or perceived levels of performance exertion.

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