Caffeine's Impact in Sitting Volleyball: Performance and Conclusion

In 13 elite sitting volleyball players, acute low‑dose caffeine produced a modest, task‑specific improvement in performance metrics—best read as a targeted performance signal rather than evidence of a broad ergogenic effect across skills.

The randomized, double‑blind crossover trial tested low‑dose caffeine (3 mg/kg) versus placebo in 13 elite male athletes from a national sitting volleyball team. Participants completed standardized serve, spike, and speed‑endurance protocols under each condition with a 48‑hour washout and blinded administration. Endpoints were serve speed, spike speed, and speed‑endurance.

Initial analysis showed a moderate improvement in serve speed with caffeine (mean difference ≈1.6 km/h, p≈0.028), though the effect did not remain statistically significant after Bonferroni correction (adjusted p≈0.084). There were no meaningful gains in spike speed (p≈0.55) or speed‑endurance (p≈0.71), and perceived exertion during endurance testing was unchanged. Collectively, the outcomes suggest an ergogenic signal limited to specific, repeatable upper‑body actions in this cohort.

Those limits plausibly reflect task complexity and sport‑specific neuromuscular demands in sitting play: upper‑limb propulsion, trunk stability requirements, and rapid perceptual–motor integration can blunt translation of central stimulant effects.

Replication in larger, mixed‑sex, sport‑specific cohorts is required before routine practice changes.

Key Takeaways:

• Low‑dose caffeine (3 mg/kg) produced a modest, non‑robust improvement in serve speed but did not improve spike speed or speed‑endurance—interpret this as a task‑specific trend, not definitive evidence.
• Athletes who depend on repeatable, explosive upper‑body serves are most likely to show any benefit; individual responses will vary, so results are best confirmed with supervised, individualized trials.
• This single small trial should not drive broad practice change; prioritize larger, sport‑specific replications and exploration of dose or genotype‑informed strategies before routine recommendation.