David Lara, Gaven Barker, Victor Alves, Alyssa Parten, Lauren G. Killen. University of North Alabama, Florence, AL.

Background: Studies investigating caffeine supplementation on soccer performance have largely focused on males completing soccer-specific drills. Females’ responses to caffeine may differ from males and drills may not mimic game play. This study examined caffeine’s effects on physical performance and perceptual responses in simulated women’s NCAA D1 soccer competition. METHODS: Nineteen (n = 19) D1 female soccer athletes (20 ± 1.2 years) completed four 60-min simulated soccer scrimmages. The first two scrimmages were two days apart, followed by the third and the fourth scrimmages a week later also two days apart. Participants were randomly assigned into two teams with regard to positions. Scrimmages one and three were baseline games; whereas, scrimmages two and four were treatment trials (double-blind, counterbalanced), in which teams were randomly assigned caffeine (6 mg/kg) or a matched placebo administered 1-hour prior. Players wore a TITAN GPS system that tracked distance traveled, speed band 1 (1.0-3.0 m/s), speed band 2 (3.0-5.0 m/s), total sprints, load, accelerations, decelerations, top speed, and sprint distance (mean and total). Acute RPE was assessed at the end of each half and session RPE (SRPE) was assessed 15-min post-match. Separate 2 (trials) x 2 (timepoints) ANOVAs were used to assess differences between trials for GPS variables and acute RPE. Paired t-tests were used to compare SRPE and post questionnaire surveys between trials. RESULTS: Main effect for acute RPE for timepoint was significant (p ≤ 0.05) with the main effect for treatment approaching significance (p = 0.08), with post hoc analysis (two-tailed, paired t-test) suggesting the higher RPE (7.1 ± 1.6 vs. 6.5 ± 1.7) in the second half. RPE for caffeine approached significance (p = 0.10). There was no significance for distance traveled, load, top speed, speed bands, and sprint distances. Treatment main effect was significant (p ≤ 0.03) for acceleration and approached significance (p = 0.07) for deceleration with post hoc tests suggesting significantly more acceleration periods (5.0 ± 4.2 vs. 3.7 ± 3.1) within the second half and deceleration periods within the first half (11.9 ± 10.5 vs. 8.9 ± 7.3) for caffeine. SRPE was not significant between caffeine and placebo (6.3 ± 1.5 vs. 6.0 ± 1.3). CONCLUSION: The caffeine trial revealed significantly more acceleration periods in the second half, thus suggesting performance improvement during soccer play plausible as acceleration periods likely reflect engagement with the ball. Despite the significantly higher acute RPE measures in the second half, participants felt intensities were similar as suggested by SRPE when participants reflected on the entire scrimmage. Extending the understanding of caffeine on soccer specific performance could benefit overall performance, with the potential to influence game outcome.

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