Abstract des Autors

The effects of carbohydrate supplementation on high-intensity exercise performance were examined in 5 moderately trained subjects (age = 28.4+/-1.5 yr). High-intensity exercise tests (initiated at the power output (PO) associated with 90% VO2 peak (mean = 201+/-21 watts) x 60 min, with drop-off in PO allowed overtime) were completed under the following randomized double blind conditions: 1) pre-exercise glucose polymer (G)/placebo during exercise (G/P), 2) G pre-exercise and during exercise (G/G), and 3) placebo pre-exercise and during exercise (P/P). Subjects ingested 300 ml of a sweetened placebo or a similarly flavored 10% G solution, immediately prior to and every 15 min during exercise. No differences were observed in PO among the 3 treatments until min 40-60 where PO was greater with G. This resulted in significantly greater total work (and less drop-off in PO) with G (G/P = 619+/-234 kj (14.5% lower than the value associated with 201 watts maintained for 60 min (724 kj))), G/G = 599+/-235 kj (17,3% lower than the value associated with 201 watts maintained for 60 min)) compared with placebo (P/P = 560+/-198 kj (22.7% drop-off in average PO)). VO2 followed a similar pattern with no differences in VO2 over min 0-40 and significantly higher VO2 in G/P and a trend for higher VO2 in G/G during min 40-60 compared to placebo. Results of the present study indicate that, compared to placebo, pre-exercise ingestion of G (30 g in 10% solution) results in less drop-off in PO during 1 hour of high-intensity exercise performance, and that no further benefit is observed when the same amount of G is also ingested every 15 min during exercise. Verf.-Referat