Acute doses of 3 and 6 mg/kg caffeine produce outcome- and phase-specific improvements in male 100-m sprinters: A randomized, double-blind, placebo-controlled crossover trial.
Tao Mei, Jianing Li, Xiangang Yang
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In 30 seconds
This randomized, double-blind, placebo-controlled crossover trial tested acute caffeine doses in 21 male 100-m sprinters. After placebo, 3 mg/kg, or 6 mg/kg, participants completed sprint and other performance tests. Both caffeine doses improved cumulative 10-, 30-, and 60-m times versus placebo: 3 mg/kg shortened them by 0.056, 0.083, and 0.123 s, respectively, and 6 mg/kg by 0.075, 0.115, and 0.175 s. The higher dose further improved 30- and 60-m times versus 3 mg/kg, while its additional reduction at 10 m was not statistically significant in the primary model.
Key findings
- Compared with placebo, 3 mg/kg caffeine shortened cumulative 10-, 30-, and 60-m times by 0.056, 0.083, and 0.123 s.
- Compared with placebo, 6 mg/kg shortened cumulative 10-, 30-, and 60-m times by 0.075, 0.115, and 0.175 s.
- Versus 3 mg/kg, 6 mg/kg further reduced 30- and 60-m times by 0.032 and 0.052 s; the 0.019-s reduction at 10 m was not statistically significant.
- Both doses improved reaction time, perceived exertion, jump height, Wingate peak and mean power, and starting-block rate of force development versus placebo; stride length and frequency were unchanged.
Why it matters
The results suggest that acute caffeine benefits in trained male sprinters vary by performance outcome and sprint phase rather than increasing uniformly with dose. The 3 mg/kg dose improved several measured outcomes, while 6 mg/kg offered additional gains for some measures, including later cumulative sprint times. This distinction may inform interpretation of caffeine’s performance effects, while the findings remain specific to the tested population and protocol.
What to keep in mind
The trial included only 21 male 100-m sprinters, so the findings may not generalize to other populations or events.