title: The ingestion of combined carbohydrates does not alter metabolic responses or performance capacity during soccer-specific exercise in the heat compared to ingestion of a single carbohydrate.
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 · kg(-1) body mass of a solution containing glucose (1 g · min(-1) glucose) (GLU), or glucose (0.66 g · min(-1)) plus fructose (0.33 g · min(-1)) (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 post-exercise muscle glycogen concentration (PLA, 62.99 ± 8.39 mmol · kg wet weight(-1); GLU 68.62 ± 2.70; mmol · kg wet weight(-1) and MIX 76.63 ± 6.92 mmol · kg wet weight(-1)) 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 (P > 0.05). However, total carbohydrate oxidation was significantly increased during MIX compared with PLA (P < 0.05). 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.
authors.affiliation: Department of Biomolecular and Sports Science, Faculty of Health and Life Sciences, Coventry University, Coventry, UK. neil.clarke@coventry.ac.uk
authors.forename: N D
authors.initials: ND
authors.lastname: Clarke
authors.forename: I T
authors.initials: IT
authors.lastname: Campbell
authors.forename: B
authors.initials: B
authors.lastname: Drust
authors.forename: L
authors.initials: L
authors.lastname: Evans
authors.forename: T
authors.initials: T
authors.lastname: Reilly
authors.forename: D P M
authors.initials: DP
authors.lastname: Maclaren
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D004032:Diet / Q000379:methods*; D019422:Dietary Sucrose / Q000494:pharmacology; D004338:Drug Combinations; D015444:Exercise / Q000502:physiology*; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006003:Glycogen / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009005:Monosaccharides / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000502:physiology; D010084:Oxidation-Reduction; D010809:Physical Fitness; D012916:Soccer / Q000502:physiology*
chemical_list: D019422:Dietary Sucrose; D004338:Drug Combinations; D009005:Monosaccharides; D005632:Fructose; D006003:Glycogen; D005947:Glucose