Effects of Creatine Monohydrate on Endurance Performance in a Trained Population: A Systematic Review and Meta-analysis

Headnote

Abstract

Background There is robust evidence that creatine monohydrate supplementation can enhance short-term high-intensity exercise in athletes. However, the effect of creatine monohydrate supplementation on aerobic performance and its role during aerobic activities is still controversial.

Objective The purpose of this systematic review and meta-analysis was to evaluate the supplementation effects of creatine monohydrate on endurance performance in a trained population.

Methods The search strategy in this systematic review and meta-analysis was designed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and PubMed/MEDLINE, Web of Science, and Scopus databases were explored from inception until 19 May, 2022. Only human experimental trials, controlled with a placebo group, evaluating the effects of creatine monohydrate supplementation on endurance performance in a trained population were analyzed in this systematic review and meta-analysis. The methodological quality of included studies was evaluated using the Physiotherapy Evidence Database (PEDro) scale.

Results A total of 13 studies satisfied all the eligibility criteria and were included in this systematic review and meta-analysis. The results for the pooled meta-analysis showed a non-significant change in endurance performance after creatine monohydrate supplementation in a trained population (p = 0.47), with a trivial negative effect (pooled standardized mean difference = - 0.07 [95% confidence interval - 0.32 to 0.18]; I² = 34.75%). Further, after excluding the studies not evenly distributed around the base of the funnel plot, the results were similar (pooled standardized mean difference = - 0.07 [95% confidence interval - 0.27 to 0.13]; I² = 0%; p = 0.49).

Conclusions Creatine monohydrate supplementation was shown to be ineffective on endurance performance in a trained population.

Clinical Trial Registration The study protocol was registered in the Prospective Register of Systematic Review (PROSPERO) with the following registration number: CRD42022327368.

1Introduction

Creatine (Cr) is a non-protein amino acid endogenously synthesized primarily in the liver and kidneys through several enzyme processes from arginine, glycine, and methionine [1, 2]. Creatine is predominantly stored in skeletal muscle (~ 95%), with ~ 66% of intramuscular Cr stored as phosphocreatine (PCr), and the remaining as free Cr [3]. However, only 60-80% of muscle Cr and PCr stores are saturated in a regular diet [3]. Hence, dietary supplementation of creatine monohydrate (CrM) could help to increase muscle Cr and...