Palmer G S, Clancy M C, Hawley J A, Rodger I M, Burke L M, Noakes T D
School of Life Science, Kingston University, Kingston Upon Thames, Surrey, England.
Int J Sports Med. 1998 Aug;19(6):415-8. doi: 10.1055/s-2007-971938.
This study examined the effects of carbohydrate ingestion on 20 km cycle time-trial (TT) performance in 14 well-trained cyclists (11 males, 3 females; peak oxygen uptake [VO2peak] 4.52 +/- 0.60 l/min; values are mean +/- SD). All subjects performed two experimental trials on their own bicycles mounted on an air-braked ergometry system (Kingcycle). Subjects were instructed to maintain the same training and dietary regimens before trials, which were conducted in a random order, 3-7 days apart, and at the same time of day for each subject. On the day of a trial, subjects reported to the laboratory and ingested an 8 ml/kg body mass bolus of either a 6.8 g/100 ml commercial carbohydrate-electrolyte (CHO) beverage (39 +/- 4 g of CHO), or a coloured, flavoured placebo. Ten min after finishing the drink, subjects commenced a 5 min warm-up at 150 W, before commencing the 20 km TT. The average power output (312 +/- 40 vs 311 +/- 38 W) and heart-rate (171 +/- 6 vs 171 +/- 5 beats/min for CHO and placebo, respectively) during the two rides did not differ between treatments. Accordingly, the performance times for the two TT's were the same (27:41 +/- 1:39 min:sec, for both CHO and placebo). We conclude that the ingestion of approximately 40 g of carbohydrate does not improve maximal cycling performance lasting approximately 30 min, and that carbohydrate availability, in the form of circulating blood glucose, does not limit high-intensity exercise of this duration.
本研究调查了碳水化合物摄入对14名训练有素的自行车运动员（11名男性，3名女性；峰值摄氧量[VO2peak]为4.52±0.60升/分钟；数值为平均值±标准差）进行20公里自行车计时赛（TT）成绩的影响。所有受试者在安装了空气制动测力计系统（Kingcycle）的自己的自行车上进行了两项实验性试验。受试者被要求在试验前保持相同的训练和饮食方案，试验以随机顺序进行，间隔3 - 7天，且对每个受试者而言每天的时间相同。在试验当天，受试者前往实验室，摄入8毫升/千克体重的6.8克/100毫升市售碳水化合物 - 电解质（CHO）饮料（39±4克CHO）或有颜色、味道的安慰剂。喝完饮料10分钟后，受试者在150瓦功率下进行5分钟热身，然后开始20公里计时赛。两种骑行过程中的平均功率输出（CHO组为312±40瓦，安慰剂组为311±38瓦）和心率（CHO组和安慰剂组分别为171±6次/分钟和171±5次/分钟）在不同处理之间没有差异。因此，两次计时赛的成绩相同（CHO组和安慰剂组均为27:41±1:39分钟:秒）。我们得出结论，摄入约40克碳水化合物并不能提高持续约30分钟的最大骑行成绩，并且以循环血糖形式存在的碳水化合物可用性并不限制该时长的高强度运动。
