目的：本研究目的在探討中等強度運動前增補支鏈胺基酸對肌肉損傷指標的影響。方法：8名健康男大生參加雙盲交叉實驗，在運動前60分鐘分別增補92mg/kg BW支鏈胺基酸(BCAA)或安慰劑(Placebo, PLA)膠囊，安靜休息後進行60% VO(下標 2max)固定式腳踏車運動30分鐘。於增補前、運動前立即與運動後第0、15、60分鐘，採集血液以測量肌酸激酶與乳酸脫氫酶，所得數據以二因子重複量數變異數分析進行檢定，α=.05為顯著水準。結果：CK與LDH於實驗處理與時間的交互作用均未達顯著；CK在實驗處理與時間方面均達顯著，其中BCAA處理的CK顯著低於PLA(BCAA:167.30±90.55U/L; PLA:200.17±117.46U/L, p<.05)；LDH在時間方面達顯著。結論：運動前60分鐘增補支鏈胺基酸可顯著降低中等強度運動後CK數值，而能降低肌肉損傷的風險。

Purpose: The purpose of this study was to examine the effect of branched-chain amino acid (BCAA) supplementation on indices of muscle damage. Methods: Eight healthy active college students participated in a double-blinded crossover study. The subjects ingested either 92 mg/kg BW of BCAA (BCAA) or placebo (PLA) capsules 60 min before exercise respectively. They exercised at 60% VO(subscript 2max) on cycle ergometer for 30 minutes. Blood samples were collected prior to supplementation, immediately prior to exercise, and 0, 15, 60 min after cycling (P0, P15, P60) for analysis of creatine kinase (CK) and lactate dehydrogenase (LDH). The data were analyzed by two-way repeated measures ANOVA and significance was accepted at α=.05. Results: No interactions between treatment and timing were found. Significant main effect was found for treatment and timing on CK and for the main effect of treatment, BCAA's response of CK were significantly lower than PLA (BCAA: 167.30±90.55 U/L; PLA: 200.17±117.46 U/L, p<.05). Significant main effect was found for timing on LDH. Conclusions: These results indicate that supplementary BCAA 60 min before cycling decreased serum concentrations of the intramuscular enzymes CK after moderate cycling exercise. The effects of BCAA supplementation are suggested to reduce the risk of muscle damage.