Saunders Michael J, Moore Rebecca W, Kies Arie K, Luden Nicholas D, Pratt Casey A
Department of Kinesiology, James Madison University, Harrisonburg, VA, USA.
Int J Sport Nutr Exerc Metab. 2009 Apr;19(2):136-49. doi: 10.1123/ijsnem.19.2.136.
This study examined whether a carbohydrate + casein hydrolysate (CHO+ProH) beverage improved time-trial performance vs. a CHO beverage delivering approximately 60 g CHO/hr. Markers of muscle disruption and recovery were also assessed. Thirteen male cyclists (VO2peak = 60.8 +/- 1.6 ml . kg-1 . min-1) completed 2 computer-simulated 60-km time trials consisting of 3 laps of a 20-km course concluding with a 5-km climb (approximately 5% grade). Participants consumed 200 ml of CHO (6%) or CHO+ProH beverage (6% + 1.8% protein hydrolysate) every 5 km and 500 ml of beverage immediately postexercise. Beverage treatments were administered using a randomly counterbalanced, double-blind design. Plasma creatine phosphokinase (CK) and muscle-soreness ratings were assessed immediately before and 24 hr after cycling. Mean 60-km times were 134.4 +/- 4.6 and 135.0 +/- 4.0 min for CHO+ProH and CHO beverages, respectively. All time differences between treatments occurred during the final lap, with protein hydrolysate ingestion explaining a significant (p < .05) proportion of between-trials differences over the final 20 km (44.3 +/- 1.6, 45.0 +/- 1.6 min) and final 5 km (16.5 +/- 0.6, 16.9 +/- 0.6 min). Plasma CK levels and muscle-soreness ratings increased significantly after the CHO trial (161 +/- 53, 399 +/- 175 U/L; 15.8 +/- 5.1, 37.6 +/- 5.7 mm) but not the CHO+ProH trial (115 +/- 21, 262 +/- 88 U/L; 20.9 +/- 5.3, 32.2 +/- 7.1 mm). Late-exercise time-trial performance was enhanced with CHO+ProH beverage ingestion compared with a beverage containing CHO provided at maximal exogenous oxidation rates during exercise. CHO+ProH ingestion also prevented increases in plasma CK and muscle soreness after exercise.
本研究考察了与每小时提供约60克碳水化合物（CHO）的CHO饮料相比，碳水化合物+酪蛋白水解物（CHO+ProH）饮料是否能改善计时赛成绩。还评估了肌肉损伤和恢复的标志物。13名男性自行车运动员（峰值摄氧量=60.8±1.6毫升·千克⁻¹·分钟⁻¹）完成了2次计算机模拟的60公里计时赛，赛程包括20公里赛道的3圈，最后是一段5公里的爬坡（坡度约5%）。参与者每5公里饮用200毫升CHO（6%）或CHO+ProH饮料（6%+1.8%蛋白水解物），运动后立即饮用500毫升饮料。饮料处理采用随机平衡的双盲设计。在骑行前和骑行后24小时评估血浆肌酸磷酸激酶（CK）和肌肉酸痛评分。CHO+ProH饮料组和CHO饮料组的平均60公里用时分别为134.4±4.6分钟和135.0±4.0分钟。各处理组之间的所有时间差异均出现在最后一圈，蛋白水解物摄入解释了最后20公里（44.3±1.6、45.0±1.6分钟）和最后5公里（16.5±0.6、16.9±0.6分钟）试验间差异的很大一部分（p<0.05）。CHO试验后血浆CK水平和肌肉酸痛评分显著升高（161±53、399±175 U/L；15.8±5.1、37.6±5.7毫米），而CHO+ProH试验后则未升高（115±21、262±88 U/L；20.9±5.3、32.2±7.1毫米）。与运动期间以最大外源氧化速率提供CHO的饮料相比，摄入CHO+ProH饮料可提高运动后期计时赛成绩。摄入CHO+ProH还可防止运动后血浆CK升高和肌肉酸痛。
