Acute effects of 3 and 6 mg·Kg(-1) caffeine on strength-power performance and isokinetic peak torque in competitive male boxers: a randomized, double-blind, placebo-controlled crossover trial

Evidence on the dose, timing, and task specificity of caffeine ingestion in combat-sport athletes remains limited. This study examined the acute effects of 3 and 6 mg·kg-1 caffeine on strength-power performance and isokinetic peak torque in male boxers.

Fifteen male boxers who met the Chinese national second-class athlete standard or higher completed a randomized, double-blind, placebo-controlled crossover trial. Each participant completed placebo (PLA), 3 mg·kg-1 caffeine (CAF3), and 6 mg·kg-1 caffeine (CAF6) conditions in randomized order, separated by a 1-week washout. Countermovement jump (CMJ), ballistic push-up (BPU), and dominant-side shoulder and knee isokinetic peak torque (PT) were assessed at baseline and during testing blocks beginning at 30 and 60 min post-ingestion. Data were analyzed using two-way repeated-measures ANOVA, with Holm adjustment applied across the 10 planned condition × time interaction tests. Reliability analyzes were supportive, and threshold-based individual classifications were exploratory.