Oosthuyse T, Carstens M, Millen A M E
Exercise Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Medical School, Johannesburg, South Africa.
Int J Sports Med. 2015 Jul;36(8):636-46. doi: 10.1055/s-0034-1398647. Epub 2015 May 5.
The protein type most suitable for ingestion during endurance exercise is undefined. This study compared co-ingestion of either 15 g/h whey or casein hydrolysate with 63 g/h fructose: maltodextrin (0.8:1) on exogenous carbohydrate oxidation, exercise metabolism and performance. 2 h postprandial, 8 male cyclists ingested either: carbohydrate-only, carbohydrate-whey hydrolysate, carbohydrate-casein hydrolysate or placebo-water in a crossover, double-blind design during 2 h of exercise at 60%W max followed by a 16-km time trial. Data were evaluated by magnitude-based inferential statistics. Exogenous carbohydrate oxidation, measured from (13)CO2 breath enrichment, was not substantially influenced by co-ingestion of either protein hydrolysate. However, only co-ingestion of carbohydrate-casein hydrolysate substantially decreased (98% very likely decrease) total carbohydrate oxidation (mean±SD, 242±44; 258±47; 277±33 g for carbohydrate-casein, carbohydrate-whey and carbohydrate-only, respectively) and substantially increased (93% likely increase) total fat oxidation (92±14; 83±27; 73±19 g) compared with carbohydrate-only. Furthermore, only carbohydrate-casein hydrolysate ingestion resulted in a faster time trial (-3.6%; 90% CI: ±3.2%) compared with placebo-water (95% likely benefit). However, neither protein hydrolysate enhanced time trial performance when compared with carbohydrate-only. Under the conditions of this study, ingesting carbohydrate-casein, but not carbohydrate-whey hydrolysate, favourably alters metabolism during prolonged moderate-strenuous cycling without substantially altering cycling performance compared with carbohydrate-only.
耐力运动期间最适合摄入的蛋白质类型尚无定论。本研究比较了每小时摄入15克乳清或酪蛋白水解物与每小时摄入63克果糖：麦芽糊精（0.8:1）对碳水化合物氧化、运动代谢和运动表现的影响。餐后2小时，8名男性自行车运动员采用交叉双盲设计，在以60%最大摄氧量进行2小时运动期间摄入以下物质：仅碳水化合物、碳水化合物-乳清水解物、碳水化合物-酪蛋白水解物或安慰剂-水，随后进行16公里计时赛。数据采用基于量级的推断统计进行评估。通过（13）CO2呼气富集测量的外源性碳水化合物氧化，并未受到任何一种蛋白质水解物共同摄入的显著影响。然而，只有碳水化合物-酪蛋白水解物的共同摄入显著降低了（98%极有可能降低）总碳水化合物氧化（平均值±标准差，碳水化合物-酪蛋白组为242±44克，碳水化合物-乳清组为258±47克，仅碳水化合物组为277±33克），与仅摄入碳水化合物相比，显著增加了（93%有可能增加）总脂肪氧化（分别为92±14克、83±27克、73±19克）。此外，与安慰剂-水相比，仅摄入碳水化合物-酪蛋白水解物可使计时赛成绩更快（-3.6%；90%置信区间：±3.2%）（95%有可能有益）。然而，与仅摄入碳水化合物相比，两种蛋白质水解物均未提高计时赛成绩。在本研究条件下，与仅摄入碳水化合物相比，摄入碳水化合物-酪蛋白而非碳水化合物-乳清水解物，有利于在长时间中度剧烈骑行期间改变代谢，而不会显著改变骑行表现。
