Abstract

This study was designed to investigate the effect of ingesting a glucose plus fructose solution on the metabolic responses to soccer-specific exercise in the heat and the impact on subsequent exercise capacity. Eleven male soccer players performed a 90 min soccer-specific protocol on three occasions. Either 3 ml _ kg71 body mass of a solution containing glucose (1 g _ min71 glucose) (GLU), or glucose (0.66 g _ min71) plus fructose (0.33 g _ min71) (MIX) or placebo (PLA) was consumed every 15 minutes. Respiratory measures were undertaken at 15-min intervals, blood samples were drawn at rest, half-time and on completion of the protocol, and muscle glycogen concentration was assessed pre- and post-exercise. Following the soccer-specific protocol the Cunningham and Faulkner test was performed. No significant differences in postexercise muscle glycogen concentration (PLA, 62.99+8.39 mmol _ kg wet weight71; GLU 68.62+2.70; mmol _ kg wet weight71 and MIX 76.63+6.92 mmol _ kg wet weight71) or exercise capacity (PLA, 73.62+8.61 s; GLU, 77.11+7.17 s; MIX, 83.04+9.65 s) were observed between treatments (P40.05). However, total carbohydrate oxidation was significantly increased during MIX compared with PLA (P50.05). These results suggest that when ingested in moderate amounts, the type of carbohydrate does not influence metabolism during soccer-specific intermittent exercise or affect performance capacity after exercise in the heat. Verf.-Referat