The Supplementation of Branched-Chain Amino Acids, Arginine, and Citrulline Improves Endurance Exercise Performance in Two Consecutive Days.
The central nervous system plays a crucial role in fatigue during endurance exercise. Branched-chain amino acids (BCAA) could reduce cerebral serotonin synthesis by competing with its precursor tryptophan for crossing the blood brain barrier. Arginine and citrulline could prevent excess hyperammonemia accompanied by BCAA supplementation. This study investigated the combination of BCAA, arginine, and citrulline on endurance performance in two consecutive days. Seven male and three female endurance runners ingested 0.17 g·kg-1BCAA, 0.05 g·kg-1arginine and 0.05 g·kg-1citrulline (AA trial) or placebo (PL trial) in a randomized cross-over design. Each trial contained a 5000 m time trial on the first day, and a 10000 m time trial on the second day. The AA trial had significantly better performance in 5000 m (AA: 1065.7 ± 33.9 s; PL: 1100.5 ± 40.4 s) and 10000 m (AA: 2292.0 ± 211.3 s; PL: 2375.6 ± 244.2 s). The two trials reported similar ratings of perceived exertion. After exercise, the AA trial had significantly lower tryptophan/BCAA ratio, similar NH3, and significantly higher urea concentrations. In conclusion, the supplementation could enhance time-trial performance in two consecutive days in endurance runners, possibly through the inhibition of cerebral serotonin synthesis by BCAA and the prevention of excess hyperammonemia by increased urea genesis.
Department of Physical Education, National Taichung University of Education , Taichung, Taiwan.
I-Shiung
IS
Cheng
Department of Physical Education, National Taichung University of Education , Taichung, Taiwan.
Yi-Wen
YW
Wang
Graduate Institute of Sport Coaching Science, Chinese Culture University , Taipei, Taiwan.
I-Fan
IF
Chen
Department of Sport Performance, National Taiwan University of Sport , Taichung, Taiwan.
Gi-Sheng
GS
Hsu
Graduate Institute of Sport Coaching Science, Chinese Culture University , Taipei, Taiwan.
Chun-Fang
CF
Hsueh
Sport Science Research Center, National Taiwan University of Sport , Taichung, Taiwan.
Chen-Kang
CK
Chang
Central fatigue; hyperammonemia; neurotransmitter; time trial; tryptophan