ORIGINAL ARTICLES  BODY COMPOSITION, NUTRITION, SUPPLEMENTATION 

The Journal of Sports Medicine and Physical Fitness 2011 March;51(1):82-8

Copyright © 2011 EDIZIONI MINERVA MEDICA

language: English

Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion

Gualano A. B. ¹, Bozza T. ¹, Lopes De Campos P. ^{1, 2}, Roschel H. ¹, Dos Santos Costa A. ¹, Luiz Marquezi M. ^{1, 2}, Benatti F. ¹, Herbert Lancha Junior A. ¹ ✉

¹ School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, SP, Brazil; ² Institute of Biology, University of Campinas, Campinas, SP, Brazil

AIM: It has been demonstrated that branched-chain amino acids (BCAA) transaminase activation occurs simultaneously with exercise-induced muscle glycogen reduction, suggesting that BCAA supplementation might play an energetic role in this condition. This study aimed to test whether BCAA supplementation enhances exercise capacity and lipid oxidation in glycogen-depleted subjects.
METHODS: Using a double-blind cross-over design, volunteers (N.=7) were randomly assigned to either the BCAA (300 mg . kg . day -1) or the placebo (maltodextrine) for 3 days. On the second day, subjects were submitted to an exercise-induced glycogen depletion protocol. They then performed an exhaustive exercise test on the third day, after which time to exhaustion, respiratory exchange ratio (RER), plasma glucose, free fatty acids (FFA), blood ketones and lactate were determined. BCAA supplementation promoted a greater resistance to fatigue when compared to the placebo (+17.2%). Moreover, subjects supplemented with BCAA showed reduced RER and higher plasma glucose levels during the exhaustive exercise test.
CONCLUSION: In conclusion, BCAA supplementation increases resistance to fatigue and enhances lipid oxidation during exercise in glycogen-depleted subjects.