Effects of Carbohydrate Mouth Rinse on Cycling Time Trial Performance: A Systematic Review and Meta-Analysis
Despite the growing number of studies reporting carbohydrate mouth rinse effects on endurance performance, no systematic and meta-analysis review has been conducted to elucidate the level of evidence of carbohydrate mouth rinse effects on cycling trial performance such as time-, work-, and distance-based trials.
The objective of this study were to establish the effect of a carbohydrate mouth rinse on cycling performance outcomes such as mean power output and time to complete a trial, together with the risk of bias in the cycling-carbohydrate mouth rinse literature.
We systematically reviewed randomized placebo-controlled trials that assessed carbohydrate mouth rinse effects on mean power output and time to complete the trial. A random-effects meta-analysis assessed the standardized mean difference between carbohydrate and placebo mouth rinses.
Thirteen studies (16 trials) were qualitatively (systematic review) and quantitatively (meta-analysis) analyzed with regard to mean power output (n = 175) and time to complete the trial (n = 151). Overall, the reviewed studies showed a low risk of bias and homogeneous results for mean power output (I2 = 0%) and time to complete the trial (I2 = 0%). When compared with placebo, the carbohydrate mouth rinse improved mean power output (standardized mean difference = 0.25; 95% confidence interval 0.04–0.46; p = 0.02), but not the time to complete the trial (standardized mean difference = − 0.13; 95% confidence interval − 0.36 to 0.10; p = 0.25).
The present systematic and meta-analytic review supports the notion that a carbohydrate mouth rinse has the potential to increase mean power output in cycling trials, despite showing no superiority over placebo in improving time to complete the trials.
Flávio Oliveira Pires is grateful to the National Council for Scientific and Technological Development (CNPq-Brazil) for his researcher scholarship (#307072/2016-9). The authors thank ES Chambers, TN Kulaksız, and RM James for providing the requested data.
Compliance with Ethical Standards
This analysis is part of a carbohydrate mouth rinse project supported by the São Paulo Research Foundation (FAPESP-Brazil) (#2016/16496-3). This study was financed in part by the Coordination of Improvement of Higher Education Personnel (CAPES-Brazil), Finance Code 001 (Cayque Brietzke, Hélio José Coelho-Júnior, Paulo Estevão Franco-Alvarenga and Rodrigo Silveira).
Conflict of interest
Cayque Brietzke, Paulo Estevão Franco-Alvarenga, Hélio José Coelho-Júnior, Rodrigo Silveira Silva, Ricardo Yukio Asano, and Flávio Oliveira Pires have no conflicts of interest that are directly relevant to the contents of this review.
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