ArticleBMC sports science, medicine & rehabilitation2025
The effect of low dose caffeine powder supplementation on serve speed, spike speed, and speed-endurance in elite sitting volleyball players: a randomized double-blind crossover study.
Article in BMC sports science, medicine & rehabilitation, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT07056231 (The Effect of Low Dose Caffeine on Serve Speed, Spike Speed, and Speed-Endurance in Elite Sitting Volleyball Players), which is not on this map. Cited by 1 paper, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
The Effect of Low Dose Caffeine on Serve Speed, Spike Speed, and Speed-Endurance in Elite Sitting Volleyball Players: A Randomized Double-Blind Crossover Study
Who cites it
1 citing paper in PubMed, 1 synthesis or guideline pooled it.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
10 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundSitting volleyball relies heavily on upper-body strength and anaerobic capacity. Serve, spike, and speed-endurance are decisive skills, yet the ergogenic potential of low-dose caffeine in this Paralympic sport remains unclear. PURPOSE: To examine the acute effects of low-dose caffeine (3 mg/kg) supplementation on serve speed, spike speed, and speed-endurance in elite sitting volleyball players.
methodsUsing a randomized, double-blind, crossover design, 13 elite male athletes from the Turkish National Sitting Volleyball Team completed serve speed, spike speed, and speed-endurance tests under caffeine (CAF) and placebo (PLA) conditions.
resultsCaffeine intake produced a moderate improvement in serve speed (p = 0.028, d = 0.460); however, this effect did not remain statistically significant after Bonferroni correction (adjusted p = 0.084). No significant effects were observed for spike speed (p = 0.547, d = 0.166) or speed-endurance performance (p = 0.709, d = 0.111). Perceived exertion during the speed-endurance test was similarly high in both conditions.
conclusionsLow-dose caffeine may offer a trend toward improved serve performance, but the effect was not robust after statistical adjustment, and no benefits were observed for spike speed or speed-endurance. These findings highlight that caffeine's ergogenic effects are context-dependent and shaped by task complexity and sport-specific motor demands. Further research with larger and more diverse samples, genotype-based subgroups, and varied dosing strategies is warranted to clarify caffeine's role in adaptive sports.
trial registrationThe randomized controlled trial was retrospectively registered on 21/06/2025 at ClinicalTrials.gov, under the registration number NCT07056231.
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