Effect of caffeine on perceptions of leg muscle pain during moderate intensity cycling exercise

This double-blind, within-subjects experiment examined the effect of ingesting a large dose of caffeine on perceptions of leg muscle pain during moderate intensity cycling exercise. Low-caffeine-consuming college-aged males (n = 16) ingested either caffeine (10 mg × kg^-1 body weight) or placebo and 1 hour later completed 30 minutes of moderate intensity cycling exercise (60% V̇O_2peak). The order of drug administration was counter-balanced. Perceptions of leg muscle pain as well as work rate, heart rate, and oxygen uptake (VO₂) were recorded during exercise. Leg muscle pain ratings were significantly and moderately reduced after a high dose of caffeine. This observation suggests that prior reports showing caffeine improves endurance exercise performance might be partially explained by caffeine's hypoalgesic properties. It also suggests that moderate intensity cycling exercise has promise as a useful experimental model for the study of naturally occurring muscle pain.