Isolated ingestion of caffeine and sodium bicarbonate on repeated sprint performance: A systematic review and meta-analysis

Abstract Objectives This study is a systematic review and meta-analysis aimed at investigating the isolated effects of caffeine and sodium bicarbonate (NaHCO 3 ) ingestion on repeated sprint ability (RSA). Methods Following a search through PubMed and Scopus, 13 studies (7 with caffeine and 6 with NaHCO 3 ) were found to meet inclusion criteria. Random-effects of standardized mean difference (SMD) for total work and best sprint performance was examined. Study quality was assessed using QualSyst. Results The meta-analysis indicated that caffeine ingestion did not improve the total work done (weighted average effect size Hedges’s g = −0.01, 95%CI: −0.32 to 0.31, p = 0.97), best sprint (weighted average effect size Hedges’s g = −0.02, 95% CI: −0.32 to 0.27; p = 0.87) or last sprint performance (weighed average effect size Hedge’s g = −0.27, 95%CI: −0.68 to 0.14; p = 0.20), when compared with a placebo condition. Similarly, NaHCO 3 ingestion did not improve the total work done (weighted average effect size Hedges’s g = 0.43, 95% CI: −0.11 to 0.97, p = 0.12), best sprint (weighted average effect size Hedges’s g = 0.02, 95% CI −0.30 to 0.34; p = 0.90) or last sprint performance (weighted average effect size Hedge’s g = 0.20, 95%CI: −0.13 to 0.52, p = 0.14), compared with a placebo condition. Quality assessment of selected articles was classified as strong. Conclusion This meta-analysis provides evidence that repeated sprint ability is not affected by acute ingestion of caffeine or NaHCO 3 .