The Effects of Three Different Doses of Caffeine on Jumping and Throwing Performance: A Randomized, Double-Blind, Crossover Study

PURPOSE: To examine the acute effects of three doses of caffeine on upper- and lower-body ballistic exercise performance, and to explore if habitual caffeine intake impacts the acute effects of caffeine ingestion on ballistic exercise performance. METHODS: Twenty recreationally active male participants completed medicine ball throw and vertical jump tests under four experimental conditions (placebo, 2, 4, and 6 mg·kg-1 of caffeine). RESULTS: One-way repeated measures ANOVA with subsequent post hoc analyses indicated that performance in the medicine ball throw test improved, compared to placebo, only with a 6 mg·kg-1 dose of caffeine (P=0.032). Effect size, calculated as the mean difference between the two measurements divided by the pooled standard deviation, amounted to 0.29 (+3.7%). For the vertical jump test, all three caffeine doses were effective (compared to placebo) for acute increases in performance (P values ranged from 0.022 to 0.044 ; effect sizes from 0.35 to 0.42 ; percent changes from +3.7% to +4.1%). A two-way repeated measures ANOVA indicated that there was no significant group x condition interaction effect, suggesting comparable responses between low (≤100 mg·day-1) and moderate-to-high (>100 mg·day-1) caffeine users to the experimental conditions. CONCLUSIONS: Caffeine doses of 2, 4, and 6 mg·kg-1 seem to be effective for acute enhancements in lower- body ballistic exercise performance in recreationally trained male individuals. For the upper-body ballistic exercise performance, only a caffeine dose of 6 mg·kg-1 seems to be effective. The acute effects of caffeine ingestion do not seem to be impacted by habitual caffeine intake ; however, this requires further exploration.