Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis
Grgic J, Trexler ET, Lazinica B, Pedisic Z
Journal of the International Society of Sports Nutrition · 239 citations
How it was studied
- Design
- Meta-analysis (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
Based on full-text disclosure statement.
Publication
- Published
- 2018-01-05 · J Int Soc Sports Nutr · vol. 15 · issue 1 · p. 11
- Publisher
- Springer Science+Business Media
- Cited
- 367 citations · more than 99% of similar papers · 6.4× the field average
- Impact
- Top 10% most cited in its field
- References
- 45 works
- Access
- Open access (journal) · OTHER-OA
- Research areas
- Coffee research and impacts · Smoking Behavior and Cessation · Tea Polyphenols and Effects
- Keywords
- Caffeine, Medicine, Meta-analysis, Placebo, Confidence interval, Blinding, Ingestion, Sarcopenia, Internal medicine, Physical therapy, Randomized controlled trial, Pathology
- MeSH
- muscle, skeletal, humans, caffeine, muscle strength, athletes, performance-enhancing substances, sports nutritional physiological phenomena
4 authors
From AU, US, HR
- Jozo GrgićVictoria University
- Eric T. TrexlerUniversity of North Carolina at Chapel Hill
- Bruno LazinicaUniversity of Osijek
- Željko Pedišić · correspondingVictoria University
Abstract
Background
Caffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power.
Methods
A search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump. Meta-analyses of standardized mean differences (SMD) between placebo and caffeine trials from individual studies were conducted using the random effects model.
Results
Ten studies on the strength outcome and ten studies on the power outcome met the inclusion criteria for the meta-analyses. Caffeine ingestion improved both strength (SMD = 0.20; 95% confidence interval [CI]: 0.03, 0.36; p = 0.023) and power (SMD = 0.17; 95% CI: 0.00, 0.34; p = 0.047). A subgroup analysis indicated that caffeine significantly improves upper (SMD = 0.21; 95% CI: 0.02, 0.39; p = 0.026) but not lower body strength (SMD = 0.15; 95% CI: -0.05, 0.34; p = 0.147).
Conclusion
The meta-analyses showed significant ergogenic effects of caffeine ingestion on maximal muscle strength of upper body and muscle power. Future studies should more rigorously control the effectiveness of blinding. Due to the paucity of evidence, additional findings are needed in the female population and using different forms of caffeine, such as gum and gel.
Abstract via Europe PMC. Copyright remains with the authors or publisher (CC BY).
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