Valentine Rudy J, Saunders Michael J, Todd M Kent, St Laurent Thomas G
Department of Kinesiology, James Madison University, Harrisonburg, VA 22807, USA.
Int J Sport Nutr Exerc Metab. 2008 Aug;18(4):363-78. doi: 10.1123/ijsnem.18.4.363.
Carbohydrate-protein (CHO+Pro) beverages reportedly improve endurance and indices of muscle disruption, but it is unclear whether these effects are related to total energy intake or specific effects of protein.
The authors examined effects of CHO+Pro on time to exhaustion and markers of muscle disruption compared with placebo (PLA) and carbohydrate beverages matched for carbohydrate (CHO) and total calories (CHO+CHO).
Eleven male cyclists completed 4 rides to exhaustion at 75% VO2peak. Participants consumed 250 ml of PLA, CHO (7.75%), CHO+CHO (9.69%), or CHO+Pro (7.75%/1.94%) every 15 min until fatigue, in a double-blind design.
Time to exhaustion was significantly longer (p<.05) in CHO+Pro (126.2+/-25.4 min) and CHO+CHO (121.3+/-36.8) than PLA (107.1+/-30.3). CHO (117.5+/-24.2) and PLA were not significantly different. Similarly, CHO+Pro was not significantly different from CHO and CHO+CHO. Postexercise plasma creatine kinase was lower after CHO+Pro (197.2+/-149.2 IU/L) than PLA (407.4+/-391.3), CHO (373.2+/-416.6), and CHO+CHO (412.3+/-410.2). Postexercise serum myoglobin was lower in CHO+Pro (47.0+/-27.4 ng/mL) than all other treatments (168.8+/-217.3, 82.6+/-71.3, and 72.0+/-75.8). Postexercise leg extensions at 70% 1RM were significantly greater 24 hr after CHO+Pro (11.3+/-4.1) than PLA (8.8+/-3.7), CHO (9.7+/-4.3), and CHO+CHO (9.5+/-3.6).
These findings suggest that at least some of the reported improvements in endurance with CHO+Pro beverages might be related to caloric differences between treatments. Postexercise improvements in markers of muscle disruption with CHO+Pro ingestion appear to be independent of carbohydrate and caloric content and were elicited with beverages consumed only during exercise.
据报道，碳水化合物 - 蛋白质（CHO + Pro）饮料可提高耐力并改善肌肉损伤指标，但尚不清楚这些效果是与总能量摄入有关还是蛋白质的特定作用。
作者研究了与安慰剂（PLA）以及碳水化合物和总热量匹配的碳水化合物饮料（CHO + CHO）相比，CHO + Pro对力竭时间和肌肉损伤标志物的影响。
11名男性自行车运动员以75%的最大摄氧量（VO2peak）完成4次力竭骑行。参与者采用双盲设计，每15分钟饮用250毫升PLA、CHO（7.75%）、CHO + CHO（9.69%）或CHO + Pro（7.75%/1.94%），直至疲劳。
CHO + Pro组（126.2±25.4分钟）和CHO + CHO组（121.3±36.8分钟）的力竭时间显著长于PLA组（107.1±30.3分钟）（p <.05）。CHO组（117.5±24.2分钟）和PLA组无显著差异。同样，CHO + Pro组与CHO组和CHO + CHO组无显著差异。运动后，CHO + Pro组的血浆肌酸激酶（197.2±149.2 IU/L）低于PLA组（407.4±391.3）、CHO组（373.2±416.6）和CHO + CHO组（412.3±410.2）。运动后，CHO + Pro组的血清肌红蛋白（47.0±27.4 ng/mL）低于所有其他处理组（168.8±217.3、82.6±71.3和72.0±75.8）。CHO + Pro组运动后24小时以70%的1RM进行腿部伸展的次数显著多于PLA组（8.8±3.7）、CHO组（9.7±4.3）和CHO + CHO组（9.5±3.6）。
这些发现表明，至少CHO + Pro饮料所报道的耐力改善中的一些可能与处理组之间的热量差异有关。运动后摄入CHO + Pro对肌肉损伤标志物的改善似乎与碳水化合物和热量含量无关，并且仅在运动期间饮用的饮料即可引发。
