Abstract
The purpose of this study was to investigate the effects of caffeine on maximum voluntary contractions of the dominant knee extension and flexion muscles in 12 male intercollegiate track sprinters. Caffeine (5 mg.kg-1) and placebo (225 mg methylcellulose) gelatin capsules were administered orally in randomly assigned order. Muscle function was measured isokinetically by a Cybex II dynamometer interfaced with a data reduction computer. Six repetitions maximum of the extensors and flexors were performed at three sequential ordered speeds (30 degrees, 150 degrees and 300 degrees s-1) with a one-minute rest between varying velocities. Peake torque and power were than assessed after treatment conditions, as well as a fatigue index calculated from a series of 60 repetitions maximum ato 150 degrees s-1. Results of the 2 X 3 ANOVA and paired t-test indicated no difference in measures of peak torque and power at the varying contracting velocities and fatigue index after caffeine ingestion. These findings indicate the ingestion of caffeine in a small dose exerts no ergogenic effect on muscle function under anaerobic conditions.