The Repository @ St. Cloud State

Open Access Knowledge and Scholarship

Date of Award


Culminating Project Type


Degree Name

Exercise Science: M.S.




School of Health and Human Services

First Advisor

David Bacharach

Second Advisor

Glenn Street

Third Advisor

David Robinson

Keywords and Subject Headings

Caffeine, Effects, Reaction Time, Power, Sprint Time


This study aimed to determine how caffeine affects reaction time, peak muscle power calculated from vertical jump height, and 30 meter sprint time. Each individual ingested either a placebo (white flower) or 5 mg/kg of caffeine in addition to their estimated daily average caffeine consumption (mg). After 60 minutes of rest, subjects (N=15) performed a reaction time test followed by a vertical jump test and a timed 30m sprint. The dependent measures were reaction time (msec), peak muscle power (watts) calculated from vertical jump height (cm) and 30m sprint times (s). A covariate of habitual or naive caffeine users was also included in the analysis. The analysis of covariance (ANCOVA) showed the covariate (habitual vs. naive) was not significant (p=0.23) as well as the treatments (p=0.17) for reaction time. Peak muscle power was also not significant for the covariate (p=0.53) and treatment (p=0.55). Results for 30m sprint however, were significant for the covariate (p=0.006) and treatment (p=0.003). Sprint data were subsequently split into the habitual and naive groups and paired t-tests were performed resulting in significance (p=0.02) for habitual caffeine users and no significance (p=0.70) for naive caffeine users. Reaction time and peak muscle power inferred by vertical jump performance were not different when tested alone; suggesting the increase in sprint time is a result of testing both measures together. When combined, reaction time and peak power were contributing factors to show significance for the sprint; an additional factor being overall muscle power. As an adenosine receptor antagonist, caffeine in an adequate dose, could increase central nervous system excitation thereby increasing muscular firing to improve 30m sprint time.



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