Dose-dependent effect of caffeine supplementation on judo-specific performance and training activity: a randomized placebo-controlled crossover trial

Study answer

What this study found

Overall, caffeine improved judo-specific performance, but the effect was dose dependent. Total throws in the Special Judo Fitness Test improved with caffeine (χ2 = 28.03, P < 0.001, W = 0.32), with 6 and 9 mg/kg performing better than 3 mg/kg, placebo, or baseline, and 9 mg/kg exceeding 6 mg/kg. In Randori, total attacks also improved (F = 2.81, P = 0.047, η2p = 0.12); 9 mg/kg was higher than baseline or placebo, and 6 mg/kg was higher than placebo but similar to baseline. Habitual caffeine use moderated the response: among caffeine consumers, only 9 mg/kg clearly increased total throws,…

Study & population

Randomized, double-blind, placebo-controlled crossover trial in 22 healthy, highly trained male judoists from Polish clubs.

Intervention

Acute caffeine supplementation was tested at 3, 6, and 9 mg/kg body weight, administered orally as pure pharmaceutical caffeine dissolved in 350 mL water 60 minutes before testing.

Key limitation

Small sample size and male-only population limit generalizability.

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Original abstract