Abstract

This study investigated the effects of two different doses of caffeine on endurance cycle time trial performance in male athletes. Using a randomised, placebo-controlled, double-blind crossover study design, sixteen well-trained and familiarised male cyclists (Mean+s: Age = 32.6 + 8.3 years; Body mass = 78.5 + 6.0 kg; Height = 180.9+5.5 cm V O2peak = 60.4 + 4.1 ml . kg1 min.-1) completed three experimental trials, following training and dietary standardisation. Participants ingested either a placebo, or 3 or 6 mg /kg body mass of caffeine 90 min prior to completing a set amount of work equivalent to 75% of peak sustainable power output for 60 min. Exercise performance was significantly (P<0.05) improved with both caffeine treatments as compared to placebo (4.2% with 3 mg /kg body mass and 2.9% with 6 mg / kg body mass). The difference between the two caffeine doses was not statistically significant (P=0.24). Caffeine ingestion at either dose resulted in significantly higher heart rate values than the placebo conditions (P<0.05), but no statistically significant treatment effects in ratings of perceived exertion (RPE) were observed (P=0.39). A caffeine dose of 3 mg/kg body mass appears to improve cycling performance in well-trained and familiarised athletes. Doubling the dose to 6 mg / kg body mass does not confer any additional improvements in performance.