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: Age¼32.6+8.3 years; Body mass¼78.5+6.0 kg; Height¼180.9+5.5 cm _V O2peak¼60.4+4.1 ml kg71 min71) completed three experimental trials, following training and dietary standardisation. Participants ingested either a placebo, or 3 or 6 mg kg71 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 (P50.05) improved with both caffeine treatments as compared to placebo (4.2% with 3 mg kg71 body mass and 2.9% with 6 mg kg71 body mass). The difference between the
two caffeine doses was not statistically significant (P¼0.24). Caffeine ingestion at either dose resulted in significantly higher heart rate values than the placebo conditions (P50.05), but no statistically significant treatment effects in ratings of perceived exertion (RPE) were observed (P¼0.39). A caffeine dose of 3 mg kg71 body mass appears to improve cycling performance in well-trained and familiarised athletes. Doubling the dose to 6 mg kg71 body mass does not confer any additional improvements in performance. Verf.-Referat