Effect of an Absolute Dose of Encapsulated Caffeine on Cycling Time Trial Performance in Average College-age Women

Event Center BC

Few studies have examined ingestion of an absolute dose of caffeine in capsule form on the exercise performance of women with an average fitness level. PURPOSE: To investigate the effect of an absolute dose of encapsulated caffeine on cycling time-trial performance in women of average fitness level. METHODS: Four women (mean ± SD; age: 23±3 y, height: 164.2±6.0 cm, weight: 63.2±3.2 kg, body fat: 22.0±2.2%, VO2max: 35.1±5.9 mL/kg/min) participated in a pretest to assess VO2max followed by two experimental trials assigned in a double-blind, crossover design. During experimental trials, participants ingested either 600 mg of encapsulated caffeine or a placebo, followed by 60 min of seated rest. Then, 45 minutes of steady-state cycling at 50% VO2max was performed, immediately followed by a 15-min time trial to complete as much work as possible. RESULTS: There was no significant difference between trials in total work completed (caffeine: 123.7±20.4 kJ, placebo: 121.5±19.3 kJ; p=0.45), mean power output (caffeine: 137.5±22.6 kJ, placebo: 134.7±22.3 kJ; p=0.19), and peak power output (caffeine: 210.8±15.2 kJ, placebo: 213.8±34.0 kJ; p=0.82). There was no significant difference between trials in rating of perceived exertion at the end of the 15-min time trial (caffeine: 17.8±2.6, placebo: 18.8±1.3; p=0.25). CONCLUSIONS: Preliminary results of the current study did not show an ergogenic effect of an absolute dose of encapsulated caffeine on a 15-min cycling time trial performance in women of average aerobic fitness.