EFFECTS OF CARBOHYDRATE INGESTION ON SOCCER SPECIFIC SKILL TESTS PERFORMED IN THE HEAT 721

Abstract

The effects of carbohydrate ingestion on the performance of soccer specific skills during a simulated match undertaken in hot humid conditions was evaluated. Subjects were six internationally competitive junior soccer players from the Australian Institute of Sport Soccer Team (16.8±0.5 yr; 75.8±7.1 kg; VO2peak = 56±3 ml·kg-1.min-1, mean ± SD). Subjects were familiarised with a battery of soccer-specific skill tests including a 20m sprint, ball dribbling, goal shooting, and 3 Acuvision™ tests which measured pro-action/reaction (PRO/REAC), visual concentration, and reaction time. Each subject completed 2 trials separated by one week during which these tests were performed before, during and after a 60-min treadmill protocol(=9.5 km) in hot humid conditions (32°C, 60% r.h.). The treadmill protocol was designed to simulate the typical exercise requirements of a soccer match, and consisted of exercise of varying intensities (5-19 km hr-1), with a change in running velocity each 15 sec. During each trial subjects consumed 1.6 L of either a carbohydrate-electrolyte (CHO) or an artificially sweetened electrolyte (PLACEBO) drink tested in a randomised counterbalanced order. Mean total sweat loss (=2.8 L) did not differ between trials. Blood glucose concentrations were significantly higher following the CHO trial (P= 0.03), although mean glucose concentrations remained above pre-exercise levels during the placebo trial. All subjects reported that they felt and performed better during the CHO trial. Despite a perception of fatigue following the treadmill run, there were no significant decrements in soccer specific performance tests with either trial with the exception of PRO/REAC scores which were significantly lower on the PLACEBO trial (50.5±4.0 v 52.2±3.2; P = 0.04). Additional research is required to understand the effects of CHO on soccer performance in hot humid conditions.