Purpose. To conduct a narrative review of relevant studies comparing the impact of different resistance training (RT) volumes on muscle hypertrophy and lean body mass. Methods. Studies were eligible for inclusion if they were clinical trials comparing the effects of different RT volumes on muscle hypertrophy and body composition. Overall, 22 articles were considered relevant and included in this review after an extensive literature hand search of the following databases: SciELO, PubMed/MEDLINE, Scopus, SPORTDiscus, LILACS, and Web of Science. Results. Of the 22 studies, 6 showed greater effects of high-volume, 1 showed greater effects of low-volume, and the remaining studies showed no difference between high- and low-volume RT. Five studies that revealed better results for higher volume were performed in untrained people, 1 concerned trained people, and the study that presented better results for lower volume referred to trained subjects. High heterogeneity was observed in the studies’ methodology regarding training protocols, population characteristics, length of intervention, supervision status, and measures of muscle size and body composition. Conclusions. Our findings suggest that muscle size and lean body mass are not mainly affected by RT volume and that other variables, especially the intensity of effort, should be considered in RT prescription. In this sense, increased volume could be beneficial, especially when training with low effort or when effort is not well controlled. However, it is important to note that there seems to be a ceiling effect and the use of higher volumes might be detrimental to muscle hypertrophy over a long term.
The impact of resistance training volume on muscle size and lean body mass: to infinity and beyond?