Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis
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 str...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2018-03-01
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| Series: | Journal of the International Society of Sports Nutrition |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1186/s12970-018-0216-0 |
| _version_ | 1827817741362397184 |
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| author | Jozo Grgic Eric T. Trexler Bruno Lazinica Zeljko Pedisic |
| author_facet | Jozo Grgic Eric T. Trexler Bruno Lazinica Zeljko Pedisic |
| author_sort | Jozo Grgic |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-12T00:37:58Z |
| format | Article |
| id | doaj.art-261ddb8c4b654bf9a337d852976d63ca |
| institution | Directory Open Access Journal |
| issn | 1550-2783 |
| language | English |
| last_indexed | 2024-03-12T00:37:58Z |
| publishDate | 2018-03-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Journal of the International Society of Sports Nutrition |
| spelling | doaj.art-261ddb8c4b654bf9a337d852976d63ca2023-09-15T09:19:29ZengTaylor & Francis GroupJournal of the International Society of Sports Nutrition1550-27832018-03-0115110.1186/s12970-018-0216-012130030Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysisJozo Grgic0Eric T. Trexler1Bruno Lazinica2Zeljko Pedisic3Institute of Sport, Exercise and Active Living (ISEAL), Victoria UniversityApplied Physiology Laboratory, Department of Exercise and Sport ScienceFaculty of Education, Department of KinesiologyInstitute of Sport, Exercise and Active Living (ISEAL), Victoria UniversityBackground 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.http://dx.doi.org/10.1186/s12970-018-0216-0ergogenic aidperformancepowerdata synthesis |
| spellingShingle | Jozo Grgic Eric T. Trexler Bruno Lazinica Zeljko Pedisic Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis Journal of the International Society of Sports Nutrition ergogenic aid performance power data synthesis |
| title | Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis |
| title_full | Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis |
| title_fullStr | Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis |
| title_full_unstemmed | Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis |
| title_short | Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis |
| title_sort | effects of caffeine intake on muscle strength and power a systematic review and meta analysis |
| topic | ergogenic aid performance power data synthesis |
| url | http://dx.doi.org/10.1186/s12970-018-0216-0 |
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