Caffeine Gum Improves Reaction Time but Reduces Composure Versus Placebo During the Extra-Time Period of Simulated Soccer Match-Play in Male Semiprofessional Players.

Abstract

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3years, stature: 1.78 ± 0.06m, mass: 75 ± 9kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200mg; caffeine) or control (0mg; placebo) gum for 5min following 90min of soccer-specific exercise. Perceptual-cognitive skills (i.e.,passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30m) were measured at pretrial, half-time, 90min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8AU to post: 90.7 ± 0.8AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8AU to post: 88.2 ± 0.8AU; p < .01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8AU to post: 65.9 ± 0.8AU) versus placebo (pre: 68.8 ± 0.8AU to post: 68.3 ± 0.8AU; p < .01). Caffeine gum did not influence any other variables (p > .05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions.