Ergogenic Effects of Acute Caffeine Intake on Muscular Endurance and Muscular Strength in Women: A Meta-Analysis

• Main Authors: Jozo Grgic, Juan Del Coso
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: ergogenic aid; supplements; resistance exercise
• Online Access: https://www.mdpi.com/1660-4601/18/11/5773

This meta-analysis aimed to explore the effects of caffeine ingestion on muscular endurance and muscular strength in women. Five databases were searched to find relevant studies. A random-effects meta-analysis of standardized mean differences (SMD) was performed for data analysis. Subgroup meta-analyses explored the effects of caffeine on upper-body and lower-body muscular endurance and muscular strength. Eight crossover placebo-controlled studies were included in the review. In the main meta-analysis that considered data from all included studies, there was a significant ergogenic effect of caffeine on muscular endurance (SMD = 0.25; <i>p</i> = 0.027) and muscular strength (SMD = 0.18; <i>p</i> < 0.001). In a subgroup analysis that considered only upper-body exercises, there was a significant ergogenic effect of caffeine on muscular endurance (SMD = 0.20; <i>p</i> = 0.007) and muscular strength (SMD = 0.17; <i>p</i> < 0.001). In a subgroup analysis that considered only lower-body exercises, there was no significant difference between caffeine and placebo for muscular endurance (SMD = 0.43; <i>p</i> = 0.092) or muscular strength (SMD = 0.16; <i>p</i> = 0.109). The main finding of this meta-analysis is that caffeine ingestion has a significant ergogenic effect on muscular endurance and muscular strength in women. The effects reported in this analysis are similar to those previously observed in men and suggest that women may use caffeine supplementation as an ergogenic aid for muscular performance. Future research is needed to explore the effects of caffeine on lower-body muscular endurance and muscular strength in this population.