van Essen Martin, Gibala Martin J
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Med Sci Sports Exerc. 2006 Aug;38(8):1476-83. doi: 10.1249/01.mss.0000228958.82968.0a.
Recent studies have reported that adding approximately 2% protein to a carbohydrate sports drink increased cycle endurance capacity compared with carbohydrate alone. However, the practical implications of these studies work are hampered by the following limitations: (a) the rate of carbohydrate ingestion was less than what is considered optimal for endurance performance, and (b) the performance test (exercise time to fatigue) did not mimic the way in which athletes typically compete (i.e., a race in which a fixed distance or set amount of work is performed as quickly as possible).
We tested the hypothesis that adding 2% protein to a 6% carbohydrate drink (CHO-PRO) would improve 80-km cycling time trial performance, as compared with a 6% carbohydrate drink (CHO) and a nonenergetic sweetened placebo (PLAC).
Ten trained male cyclists (24 +/- 2 yr; VO2peak = 63 +/- 2 mL.kg(-1).min(-1); mean +/- SE) performed an 80-km laboratory time trial (TT) on three occasions separated by 7 d. In a double-blind crossover manner, subjects ingested CHO-PRO, CHO, or PLAC at a rate of 250 mL every 15 min with no temporal, verbal, or physiological feedback.
Time to complete the TT was 4.4% lower (P < 0.002) during CHO (135 +/- 9 min) and CHO-PRO (135 +/- 9) compared with PLAC (141 +/- 10), with no difference between CHO and CHO-PRO (P = 0.92).
Ingesting 6% carbohydrate at a rate of 1 L.h(-1) (60 g.h(-1)) improved an 80-km TT performance in trained male cyclists. However, adding 2% protein to a 6% carbohydrate drink provided no additional performance benefit during a task that closely simulated the manner in which athletes typically compete.
最近的研究报告称，与仅含碳水化合物的运动饮料相比，在碳水化合物运动饮料中添加约2%的蛋白质可提高自行车耐力。然而，这些研究成果的实际应用受到以下限制：（a）碳水化合物的摄入速率低于耐力表现的最佳摄入量；（b）性能测试（疲劳运动时间）没有模拟运动员通常的比赛方式（即尽可能快地完成固定距离或规定工作量的比赛）。
我们测试了一个假设，即与6%碳水化合物饮料（CHO）和无热量甜味安慰剂（PLAC）相比，在6%碳水化合物饮料（CHO-PRO）中添加2%蛋白质可提高80公里自行车计时赛成绩。
10名训练有素的男性自行车运动员（24±2岁；最大摄氧量=63±2毫升·千克-1·分钟-1；平均值±标准误）在相隔7天的三个时间段进行80公里实验室计时赛（TT）。采用双盲交叉方式，受试者每15分钟摄入250毫升CHO-PRO、CHO或PLAC，无时间、言语或生理反馈。
与PLAC（141±10分钟）相比，CHO（135±9分钟）和CHO-PRO（135±9分钟）期间完成TT的时间缩短了4.4%（P<0.002），CHO和CHO-PRO之间无差异（P=0.92）。
以1升·小时-1（60克·小时-1）的速率摄入6%碳水化合物可提高训练有素的男性自行车运动员的80公里TT成绩。然而，在一项紧密模拟运动员通常比赛方式的任务中，在6%碳水化合物饮料中添加2%蛋白质并未带来额外的成绩提升。
