Abstract

This study aimed to determine the effects of caffeine supplementation on muscle endurance, maximum strength, and ratings of perceived exertion (RPE) in individuals undergoing strength training with external resistance exercises. A search of three databases (PubMed, LiLACS, and CENTRAL) and gray literature was carried out to find randomized controlled trials, with a double-blind design, which investigated the effects of caffeine supplementation in healthy adults. Meta-analyses of weighted mean differences (WMD) and standardized mean differences (SMD) between caffeine and placebo groups from individual studies were performed using a random-effects model. Nineteen studies were included in the quantitative synthesis. Only the bench press and the leg press exercises were assessed in a sufficient number of studies to be included in meta-analyses. In the bench press exercise, caffeine supplementation improved strength resistance (WMD 0.87 (95% confidence interval (CI): 0.33, 1.41) repetitions, P = 0.001; 15 studies), and maximum strength (WMD 2.01 (95% CI: 0.20, 3.80) kg, P = 0.02; 7 studies), but showed no effect in RPE (SMD -0.45 (95% CI: −1.40, 0.48), P = 0.34, 7 studies) In the leg press exercise, no significant improvement were observed in muscle endurance (WMD: 1.24 (95% CI: −0.21, 2.70) repetitions, P = 0.09, 8 studies), maximum strength (WMD 8.49 (95% CI: −11.91, 28.90) kg, P = 0.415, 3 studies), and in RPE (SMD -0.17 (95% CI: −1.62, 1.27), P = 0.812, 3 studies). Caffeine supplementation showed a significant ergogenic effect on muscle endurance and maximum strength in the bench press exercise. More investigations are needed to clarify the contradictions in its effects regarding lower-body exercises.

摘要

本研究旨在确定补充咖啡因对接受外部阻力练习力量训练的个体的肌肉耐力、最大力量和感知用力 (RPE) 评级的影响。搜索了三个数据库（PubMed、LiLACS 和 CENTRAL）和灰色文献，以寻找随机对照试验，采用双盲设计，研究补充咖啡因对健康成人的影响。使用随机效应模型对来自个别研究的咖啡因组和安慰剂组之间的加权平均差异 (WMD) 和标准化平均差异 (SMD) 进行荟萃分析。19 项研究被纳入定量合成。在足够数量的研究中仅评估了卧推和腿部推举练习，以纳入荟萃分析。在卧推练习中，补充咖啡因提高了力量抵抗力（WMD 0.87（95% 置信区间（CI）：0.33、1.41）重复，P = 0.001；15 项研究）和最大力量（WMD 2.01（95% CI：0.20， 3.80) kg，P = 0.02；7 项研究），但对 RPE 没有影响（SMD -0.45（95% CI：-1.40，0.48），P = 0.34，7 项研究）在腿部推举运动中，没有显着改善在肌肉耐力（WMD：1.24（95% CI：-0.21, 2.70）次重复，P = 0.09，8 项研究）、最大力量（WMD 8.49（95% CI：-11.91, 28.90）kg，P = 0.415, 3研究）和 RPE（SMD -0.17（95% CI：-1.62，1.27），P = 0.812，3 项研究）。补充咖啡因对卧推运动中的肌肉耐力和最大力量有显着的增效作用。