Caffeine supplementation and reactive agility in elite youth soccer players /

Abstract

Caffeine has been shown to provide ergogenic benefits to sports performance. However, limited research is available on the effects of caffeine on agility performance. This study examined the effects of 6 mg kg -1 body mass of caffeine on performance of a reactive agility test (RAT) in 17 elite, male, youth soccer players. Using a double-blind, repeated-measures design, players completed 4 days of testing on the RAT after a standardized warm-up. Height and body mass were measured and players were accommodated to the RAT on Day 1. Day 2 was used to establish the participants' baseline performance on the RAT. Players were randomly assigned to caffeine or placebo on Day 3 and the condition was reversed on Day 4. Caffeine or placebo was ingested in a gelatin capsule 1 hour prior to performing the RAT. During days 2, 3, and 4, players completed 3 randomized run-throughs of the RAT with at least one run-through to the right and left sides to assess players' performance to their dominant and non-dominant sides. There were no significant differences in players' reaction times among the experimental conditions for reaction time to the dominant side, however, there were significantly faster reaction times to their non-dominant side with caffeine F (2, 15) = 4.185, p = .036, eta = .358. There were no significant differences among experimental conditions on players' sprint times to their dominant and non-dominant sides. There were no significant differences among conditions on players' total times to complete the RAT to their dominant side, however, total times to their non-dominant side was approaching significance F (2, 15) = 3.643, p = .051, eta = .327. There were no significant differences among conditions on players' heart rates at any point of measurement. There were no significant differences among conditions on player's RPE after the completion on the warm-up however, players' RPE at the conclusion of the RAT was significantly higher with caffeine F