The Effects of Leucine-Enriched Branched-Chain Amino Acid Supplementation on Recovery After High-Intensity Resistance Exercise.

CONTEXT: Of the 3 branched-chain amino acids (BCAA), leucine has arguably received the most attribution for the role of BCAA supplementation in alleviating symptoms of exercise-induced muscle damage and facilitation of acute performance recovery. PURPOSE: To examine whether enrichment of a standard BCAA supplement with additional leucine or a standalone leucine (LEU) supplement differentially affects exercise-induced muscle damage and performance recovery compared with a standard BCAA supplement. METHODS: A total of 22 recreationally active male and female subjects were recruited and assigned to consume a BCAA, leucine-enriched BCAA (LBCAA), or LEU supplement for 11 d. On the eighth day, subjects performed eccentric-based resistance exercise (ECRE). Lower-body mean average and peak power, plasma creatine kinase, soreness, and pain threshold were measured before and 24, 48, and 72 h after ECRE. RESULTS: LEU showed decreased mean average power (P = .02) and mean peak power (P = .01) from baseline to 48 h post-ECRE, whereas LBCAA and BCAA only trended toward a reduction at 24 hours post-ECRE. At 48 h post-ECRE, BCAA showed greater recovery of mean peak power than LEU (P = .04). At 24 h post-ECRE, LEU demonstrated a greater increase in plasma creatine kinase from baseline than BCAA (P = .04). Area under the curve for creatine kinase was greater in LEU than BCAA (P = .02), whereas BCAA and LBCAA did not differ. Only LEU demonstrated increased soreness during rest and under muscular tension at 24 and 48 h post-ECRE (P < .05). CONCLUSIONS: LBCAA failed to afford any advantages over a standard BCAA supplement for postexercise muscle recovery, whereas a LEU supplement was comparatively ineffective.

Dietary Caffeine and Polyphenol Supplementation Enhances Overall Metabolic Rate and Lipid Oxidation at Rest and After a Bout of Sprint Interval Exercise.

Jo, E, Lewis, KL, Higuera, D, Hernandez, J, Osmond, AD, Directo, DJ, and Wong, M. Dietary caffeine and polyphenol supplementation enhances overall metabolic rate and lipid oxidation at rest and after a bout of sprint interval exercise. J Strength Cond Res 30(7): 1871-1879, 2016-The purpose of this study was to investigate the effects of a caffeine-polyphenolic supplement on (a) metabolic rate and fat oxidation at rest and after a bout of sprint interval exercise (SIE) and (b) SIE performance. In a double-blind, randomized, placebo-controlled, crossover study and after an initial familiarization visit, 12 subjects (male: n = 11; female: n = 1) (body mass = 76.1 ± 2.2 kg; height = 169.8 ± 1.6 cm; body mass index = 22.7 ± 3.0 kg·m; body fat % = 21.6 ± 2.0%) underwent 2 testing sessions during which time they consumed either a caffeine-polyphenol supplement or placebo. After supplementation, resting energy expenditure, heart rate (HR), and blood pressure (BP) were assessed. Subsequently, subjects performed 30 minutes of SIE while researchers collected performance data. Subjects were then tested for post-SIE energy expenditure, HR, and BP. The caffeine-polyphenol treatment resulted in significantly (p ≤ 0.05) greater energy expenditure (+7.99% rest; +10.16% post-SIE), V[Combining Dot Above]O2 (+9.64% rest; +12.10% post-SIE), and fat oxidation rate (+10.60% rest; +9.76% post-SIE) vs. placebo at rest and post-SIE. No significant differences were detected for peak and average power at all sprint intervals between treatments. Post-SIE HR was significantly (p ≤ 0.05) greater with caffeine-polyphenol supplementation vs. placebo (90.8 ± 3.5 vs. 85.1 ± 3.6 b·min). There were no significant between-treatment differences for BP. It may be concluded that the observed thermogenic response after SIE was directly attributable to caffeine-polyphenol supplementation as opposed to an indirect manifestation of enhanced performance and work output. Collectively, these results corroborate the use of dietary caffeine and polyphenols to support efforts to reduce adiposity and improve overall body composition especially in conjunction with SIE.