Abstract des Autors

Purpose: This investigation was conducted to study the effects on sprint performance of glucose and fructose ingestion during a 15-min rest period half way through 90 min of continuous and intermittent exercise. On three occasions, eight subjects cycled at 76+/-2% VO2max for 90 min (continuous trials: CON trials) with a 15-min half-time break. Methods: On another three occasions, they cycled for 90 min between moderate (65% VO2max) and high (100% VO2max) intensity (intermittent trials: INT trials) with the same half-time. In both trials, 90-min exercise was followed by a 40-s Wingate test to evaluate remaining sprint capacity. During half-time, they consumed either 20% glucose polymer (G), 20% fructose (F) or sweet placebo (P). Ingestion of G maintained plasma glucose levels, carbohydrate oxidation rate and lower value of ratings of perceived exertion (RPE) in both trials and indicated higher sprint performance compared with P (mean power of CON trials: 614.3+/-23.3 W vs 574.0+/-22.7W, P<0.001, INT trials: 629.5+/-27.6 W vs 596.3+/-25.5 W, P<0.01). Results: Ingestion of F showed similar effect in CON trials (603.8+/-26.1 W vs 574.0+/-22.7 W, P<0.01) but had no positive effect in INT trials. Additionally, mean power of G was higher than F (629.5+/-27.6 W vs 598.4+/-34.2 W, P<0.01) in INT trials. Conclusions: These results indicated that ingestion of G during half-time of 90-min exercise could maintain carbohydrate utilization and improve sprint performance in both CON and INT trials. Verf.-Referat