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The purpose of this study was to examine the effects of caffeine on early second half sprint performance in 21 NCAA DIII women’s soccer players. The caffeine dosage attempted to approximate a liquid dosage many student athletes typically consume.


In a randomized double blind repeated measures design, subjects began the protocol after ingestion of caplets containing 3 of caffeine (CAF) and after ingestion of placebo (PLA) caplets. Pre-game, warm-up, and first half conditions were designed to maximize external validity.


An adapted version of the Loughborough Intermittent Shuttle Test was applied to replicate first half activity. Sprint performance was measured with the Running Based Anaerobic Sprint Test. Mean power, maximum power, and minimum power, were assessed under each condition. Repeated measures MANOVA was used to determine if there were significant mean vector differences between the trials.


Although mean, maximum, and minimum power in the CAF trial increased 3.2%, 3.4%, and 4% respectively, MANOVA results showed no statistically significant differences in the mean vector for power variables (Λ = .752, p > .05).


The lack of statistical significance in this study is likely attributed to the relationship between a small, although contextually plausible, relative caffeine dosage and an extended exercise time. The results also suggest caffeine ingestion of 3 should not be considered capable of improving sprint performance at the start of the second half.