The purpose of this study was to evaluate muscular adaptations between low-, moderate-, and high-volume resistance training (RT) protocols in resistance-trained men.METHODS
Thirty-four healthy resistance-trained men were randomly assigned to 1 of 3 experimental groups: a low-volume group (1SET) performing 1 set per exercise per training session (n = 11); a moderate-volume group (3SET) performing 3 sets per exercise per training session (n = 12); or a high-volume group (5SET) performing 5 sets per exercise per training session (n = 11). Training for all routines consisted of three weekly sessions performed on non-consecutive days for 8 weeks. Muscular strength was evaluated with 1 repetition maximum (RM) testing for the squat and bench press. Upper-body muscle endurance was evaluated using 50% of subjects bench press 1RM performed to momentary failure. Muscle hypertrophy was evaluated using B-mode ultrasonography for the elbow flexors, elbow extensors, mid-thigh and lateral thigh.RESULTS
Results showed significant pre-to-post intervention increases in strength and endurance in all groups, with no significant between-group differences. Alternatively, while all groups increased muscle size in most of the measured sites from pre-to-post intervention, significant increases favoring the higher volume conditions were seen for the elbow flexors, mid-thigh, and lateral thigh. CONCLUSION: Marked increases in strength and endurance can be attained by resistance-trained individuals with just three, 13-minute weekly sessions over an 8-week period, and these gains are similar to that achieved with a substantially greater time commitment. Alternatively, muscle hypertrophy follows a dose-response relationship, with increasingly greater gains achieved with higher training volumes.