Caffeine Supplementation and Time to Exhaustion at Peak Aerobic Velocity
Objective: We aimed to verify whether the caffeine supplementation has the potential to improve performance of the women athletes running until exhaustion at peak velocity when the positive expectancy is abolished.
Methods: We recruited ten women moderately trained in running with peak velocity of 13.40 ± 1.0 km•h-1. They came to the laboratory 7 times: a) familiarization; b) incremental test to determine the peak velocity; c) five different sessions of running at peak velocity until exhaustion. The participants were informed that they could be ingesting caffeine, placebo or acid lactic, and another trial with open caffeine (informed). We did not make suggestions of what they could be consuming. Nevertheless, they consumed the ergogenic aid (caffeine) that improves performance (according to the current paradigm) in all sessions (except for familiarization and control sessions).
Results: The main findings are 1) caffeine has a low chance to be an ergogenic aid; 2) expectancy matters more than the physiological effect of caffeine to improve performance.
Conclusion: Therefore, the performance improvement seems to be expectancy-dependent and we do not recommend caffeine as an ergogenic aid.