The dose-response relationship between resistance training volume and muscle hypertrophy: There are still doubts

Abstract

Within the resistance training and muscle growth research space, the importance of resistance training volume is often touted as one of, if not, the single most important variable to consider when designing a resistance training intervention, especially as it pertains to resistance trained individuals. Objectives: To examine the literature used to suggest that volume is the primary driver of skeletal muscle growth. Design and Methods: Non-systematic review. Research articles were collected using search terms such as resistance training OR resistance training volume. These terms were combined with AND: quadriceps muscle thickness, OR biceps muscle thickness, and other muscle-site related terms. Results: Studies in resistance trained individuals that suggest a dose-response relationship between resistance training volume and muscle growth have observed a magnitude of muscle growth that is greater than what is typically observed. For example, it may be common to observe a 0.1-0.25 cm increase in quadriceps muscle thickness following an intervention. However, studies have observed changes as high as 0.6-0.72 cm in quadriceps muscle thickness. In addition, there are several investigations demonstrating similar growth between lower and higher volume training protocols in resistance trained individuals. Conclusions: While resistance training volume may very well be one of the more important factors influencing the hyper trophic response in resistance trained individuals, we would suggest that the current evidence is much more ambiguous. Replication of the current findings may be necessary before strong conclusions are drawn. While some threshold of training volume is likely necessary for muscle growth, the current recommendations may exaggerate its importance.