Purpose: The purpose of this study was to examine the role of branched-chain amino acid (BCAA) supplementation during recovery from intense eccentric exercise.
Methods: Twenty-four non-weight-trained males were assigned to one of two groups: one group (supplementary, SUP) ingested BCAA beverages (n = 12); the second group (placebo, PLA) ingested artificially flavored water (n = 12). Diet was controlled throughout the testing period to match habitual intake. The eccentric exercise protocol consisted of 12 × 10 repetitions of unilateral eccentric knee extension exercise at 120% concentric one repetition maximum. On the day of the exercise, supplements were consumed 30 min before exercise, 1.5 h after exercise, between lunch and dinner, and before bed. On the following 2 d, four supplements were consumed between meals. Muscle soreness, muscle function, and putative blood markers of muscle damage were assessed before and after (1, 8, 24, 48, and 72 h) exercise.
Results: Muscle function decreased after the eccentric exercise (P < 0.0001), but the degree of force loss was unaffected by BCAA ingestion (51% ± 3% with SUP vs −48% ± 7% with PLA). A decrease in flexed muscle soreness was observed in SUP compared with PLA at 48 h (21 ± 3 mm vs 32 ± 3 mm, P = 0.02) and 72 h (17 ± 3 mm vs 27 ± 4 mm, P = 0.038). Flexed muscle soreness, expressed as area under the curve, was lower in SUP than in PLA (P = 0.024).
Conclusions: BCAA supplementation may attenuate muscle soreness, but it does not ameliorate eccentric exercise-induced decrements in muscle function or increases in reputed blood markers of muscle damage, when consumed before exercise and for 3 d after an eccentric exercise bout.
Human Performance Laboratory, Exercise Metabolism Research Group, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, UNITED KINGDOM
Submitted for publication March 2009.
Accepted for publication September 2009.
Address for correspondence: Asker E. Jeukendrup, Ph.D., Human Performance Laboratory, Exercise Metabolism Research Group, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; E-mail: firstname.lastname@example.org.