Effects of caffeine on isometric handgrip strength: A meta-analysis

J Grgic, 2022.
Clinical Nutrition ESPEN, Volume 47
January 26, 2022



Several studies explored the effects of caffeine on isometric handgrip strength, but their findings varied. Therefore, he aim of this review was to perform a meta-analysis of studies exploring the effects of caffeine on isometric handgrip strength.


Search for studies was performed through five databases (Academic Search Elite, Cochrane Library, PubMed/MEDLINE, SPORT Discus, and Scopus) with additional secondary searches. RoB 2 scale was used to evaluate the risk of bias of the included studies. The effects of caffeine vs. placebo were analyzed in a random-effects meta-analysis.


Sixteen studies were included (n = 353; n = 34females). The studies were classified as having "some concerns"(possible bias from the randomization process and in the measurement of the outcome) on the RoB 2 scale. In the main meta-analysis, caffeine ingestion enhanced isometric handgrip strength (d: 0.17; 95% confidence interval [CI]:0.10, 0.23; p < 0.001). In subgroup analyses, an ergogenic effect of caffeine on isometric handgrip strength was found when consumed in small doses(1-3 mg/kg; d: 0.20; 95% CI: 0.10, 0.30; p < 0.001), moderate-to-high doses(5-7 mg/kg; d: 0.15; 95% CI: 0.07, 0.23; p < 0.001), liquid form (d: 0.19;95% CI: 0.09, 0.30; p < 0.001), and capsule form (d: 0.15; 95% CI: 0.06,0.23; p < 0.001).


Overall, individuals interested in the acute enhancement of isometric handgrip strength may consider caffeine supplementation in small or moderate-to-high doses. However, these ergogenic effects were very small and were observed mostly among male participants.


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