title: The influence of caffeine and carbohydrate coingestion on simulated soccer performance.
abstract: Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of participants were measured routinely. Mean 15-m sprint time was faster during CAF (p = .04); over the final 15 min of exercise mean sprint times were CAF 2.48 +/- 0.15 s vs. CON 2.59 +/- 0.2 s. Explosive leg power (CMJ) was improved during CAF (52.9 +/- 5.8 vs. CON 51.7 +/- 5.7 cm, p = .03). Heart rate was elevated throughout CAF, and ratings of pleasure were significantly enhanced. There were no significant differences in passing skill, rating of perceived exertion, La, or body-mass losses between trials. The addition of caffeine to the carbohydrate-electrolyte solution improved sprinting performance, countermovement jumping, and the subjective experiences of players. Caffeine appeared to offset the fatigue-induced decline in self-selected components of performance.
authors.affiliation: Dept. of Sport and Exercise Science, University of Auckland, Auckland, New Zealand.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Gant
authors.forename: Ajmol
authors.initials: A
authors.lastname: Ali
authors.forename: Andrew
authors.initials: A
authors.lastname: Foskett
mesh_terms: D000293:Adolescent; D000328:Adult; D054874:Athletic Performance / Q000502:physiology; D002110:Caffeine / Q000008:administration & dosage / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004357:Drug Synergism; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D012916:Soccer / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D004040:Dietary Carbohydrates; D007773:Lactates; D002110:Caffeine