Randomised trial · Nutrients · 2019Conflicts declared

Caffeine and boxing performance in Olympic-level athletes

What it found

In eight Olympic-level male boxers, caffeine improved anaerobic power, jump height and neuromuscular efficiency.

It did not change muscle electrical activity or fatigue levels in the lower limbs.

What they found

Studies in people

Wingate power

Caffeine increased peak power by 6.27% and mean power by 5.21% compared with placebo, and reduced the time needed to reach peak power by 9.91%.

Jump height

Before the Wingate test, caffeine increased jump height by 2.4 cm compared with placebo. After the test, jump height dropped in both conditions, but the drop was smaller with caffeine.

Muscle activity

There were no significant differences between caffeine and placebo in the electrical activity of the muscles measured during the Wingate test.

Neuromuscular efficiency

Caffeine showed a large effect on neuromuscular efficiency at peak power in the vastus lateralis and gluteus maximus, and at mean power in the vastus lateralis and tibialis anterior.

Blood lactate

Blood lactate rose from rest to exhaustion after the Wingate test in both conditions, with no significant difference between caffeine and placebo.

Handgrip strength

There were no differences in isometric handgrip strength for caffeine, time or their combination.

What the authors conclude

“in these Olympic-level boxers, caffeine supplementation improved anaerobic performance without affecting EMG activity and fatigue levels in the lower limbs.”
San Juan AF, López-Samanes Á, Jodra P, et al, 2019

Also in their conclusions

  • They conclude that caffeine supplementation improved anaerobic performance without affecting muscle electrical activity and fatigue levels in the lower limbs in these Olympic-level boxers.
  • They report further benefits of enhanced neuromuscular efficiency in some muscles and improved reaction speed.
  • They advise that future research should focus on the effects of caffeine after repeated bouts of a specific simulated boxing combat test on both the upper and lower extremities and should also address cognitive fatigue.

How it was done

The authors say the effect of caffeine on combat sport performance or fatigue levels had not yet been addressed in the literature. They wanted to examine its effects on anaerobic performance, neuromuscular efficiency and neuromuscular fatigue in the upper and lower limbs in Olympic-level boxers.

Eight male athletes from the Spanish National Olympic Team completed two test sessions, one after taking caffeine (6 mg per kg of body weight) and one after a placebo, in a randomised double-blind, crossover design. Each session included measures of lactate, handgrip and countermovement jump, followed by a 30-second Wingate test, with muscle electrical activity recorded throughout.

What it can’t tell you

  • This was a small study of eight male Olympic-level boxers, so the results may not apply to other people or to female athletes.
  • The study measured performance in a laboratory setting, not in actual boxing competitions.

The paper

Title
Caffeine Supplementation Improves Anaerobic Performance and Neuromuscular Efficiency and Fatigue in Olympic-Level Boxers
Type
Randomised controlled trial
Evidence
Studies in people
Summarised from
Full text
Cite
San Juan AF, López-Samanes Á, Jodra P, et al (2019). Caffeine Supplementation Improves Anaerobic Performance and Neuromuscular Efficiency and Fatigue in Olympic-Level Boxers. Nutrients. doi:10.3390/nu11092120Free full textPubMed 31492050DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error