A study performed by Scoenfeld et al., (2019) researched the muscular adaptations to low-, moderate-, and high-volume resistance training protocols in resistance-trained men. Resistance training involved performing 8-12 repetitions of either one set (low volume), three sets (moderate volume), or five sets (high volume) of flat-bed bench press, seated cable row, barbell back squat, machine leg press, and unilateral machine leg extension. The study was conducted over an eight-week period, and exercises were performed until failure so weight lifted reflected ability.
Changes in muscle strength and muscle endurance were similar, regardless of the volume performed when exercising for 8-12 repetitions of each exercise. However, higher training volumes of training in the loading range were associated with greater increases in markers of muscle hypertrophy (muscle building).
This study shows that marked increases in strength can be attained by resistance-trained individuals with just 13 minute sessions per week, and that gains are similar to that achieved with a substantially greater time commitment when training in a loading range of 8-12 repetitions per exercise. Conversely, increases in muscle hypertrophy is mirrored in those who perform higher training volumes, so a greater amount of time is required for training to exhibit muscle growth gains. Volume does not appear to have any differential effect on measures of upper-body muscular endurance.