| Summary: | 碩士 === 國立臺中教育大學 === 體育學系碩士班 === 104 === Branched-chain amino acids (BCAA), L-Arginine (Arg) and L-Citrulline (Cit) have multiple physiological functions that may improve exercise performance. BCAA supplementation could suppress central fatigue by reducing the entry of free tryptophan, the precursor for serotonin, to the brain. In addition, Arg supplementation may stimulate endothelium-dependent vasodilation by increasing nitric oxide synthesis. Moreover, Cit is a colorless, water-soluble a-amino acid that is a potent endogenous precursor of Arg. Therefore, the study supposed that Cit supplementation dose-dependently may increases plasma L-arginine levels, resulted in the accelerated removed of the metabolites that may influence exercise performance. Objective: The purpose of this study was to investigate the combined effects of BCAA, Arg and Cit supplementation on race performance of long-distance running races in two consecutive days in elite athletes. Method: Thirteen Long-distance athletes received placebo or capsules with combination of BCAA, Arg and Cit (AA trial) in a randomized cross-over design repeated after 7 day wash out period. The subjects consumed 0.17g/Kg BCAA, 0.05 g/kg Arg and 0.05 g/kg Cit (AA trial) or placebo (PL trial) 1 hour before 5000m or 10000m running race. The Rating of Perceived Exertion (RPE) was recorded at before and after race. Blood samples will collected from the antecubital vein before and after running races for measuring responses of lactate, urea, glucose, NH3, non-esterified fatty acid (NEFA), free-tryptophan/BCAA. Result: The race performance of 5-km and 10-km running times were significantly improved in AA trail compared to PL trial (p<.05). Plasma free-tryptophan/BCAA concentration (p<.001) and Urea concentration (p<.05) in AA trial was significantly lower than PL trial. However, no significant different blood parameters were found between the two trials. Conclusion: This study demonstrated that oral BCAA, Arg and Cit supplementation attenuated central fatigue evidenced on reducing plasma free-tryptophan/BCAA concentrations and improved 5-km and 10-km race performance.
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