Journal Article

Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists

Kephart, Wesley C., Martin, Jeffrey S., Brooks Mobley, C., Company, Joseph M., Mac Thompson, R., Moon, Jordan R., McDonald, James R., Roberts, Michael D., Young, Kaelin C., Nie, Ben, Fox, Carlton D., Pascoe, David D., Ferguson, Brian S., Wachs, Taylor D., Arnold, Robert D.

2016

Overview

We examined if supplementing trained cyclists (32 ± 2 year, 77.8 ± 2.6 kg, and 7.4 ± 1.2 year training) with 12 g/day (6 g/day L-Leucine, 2 g/day L-Isoleucine and 4 g/day L-Valine) of either branched-chain amino acids (BCAAs, n = 9) or a maltodextrin placebo (PLA, n = 9) over a 10-week training season affected select body composition, performance, and/or immune variables. Before and after the 10-week study, the following was assessed: (1) 4-h fasting blood draws; (2) dual X-ray absorptiometry body composition; (3) Wingate peak power tests; and (4) 4 km time-trials. No group × time interactions existed for total lean mass (P = 0.27) or dual-leg lean mass (P = 0.96). A significant interaction existed for body mass-normalized relative peak power (19 % increase in the BCAA group pre- to post-study, P = 0.01), and relative mean power (4 % increase in the BCAA group pre- to post-study, P = 0.01). 4 km time-trial time to completion approached a significant interaction (P = 0.08), as the BCAA group improved in this measure by 11 % pre- to post-study, though this was not significant (P = 0.15). There was a tendency for the BCAA group to present a greater post-study serum BCAA: L-Tryptophan ratio compared to the PLA group (P = 0.08). A significant interaction for neutrophil number existed (P = 0.04), as there was a significant 18 % increase within the PLA group from the pre- to post-study time point (P = 0.01). Chronic BCAA supplementation improves sprint performance variables in endurance cyclists. Additionally, given that BCAA supplementation blunted the neutrophil response to intense cycling training, BCAAs may benefit immune function during a prolonged cycling season.

• Publisher: Springer Vienna,Springer Nature B.V
• Subject: Absorptiometry / Adult / Amino acids / Amino Acids, Branched-Chain - metabolism / Analytical Chemistry / Athletes / Bicycling / Biochemical Engineering / Biochemistry / Biomedical and Life Sciences / Blood / blood serum / Body Composition / Body mass / Body measurements / Chain branching / Cycles / Dietary Supplements - analysis / Dual energy X-ray absorptiometry / Endurance / fasting / Humans / Immune response / Immunology / Isoleucine / Leucine / Leukocytes (neutrophilic) / Life Sciences / Male / Maltodextrin / maltodextrins / Middle Aged / Muscle, Skeletal - metabolism / Neurobiology / Neutrophils / Neutrophils - immunology / Original Article / Performance enhancement / Physical Endurance / placebos / Proteomics / Seasons / Supplements / Training / Tryptophan / Valine / Young Adult