Dose-response of weekly resistance training volume and frequency of muscular adaptations in trained males

Purpose: Debate exists over how to best manipulate resistance exercise training (RET) volume, the number of weekly sets per muscle group, to optimize muscular adaptations. A linear dose-response relationship between RET volume and hypertrophy has been proposed for ≤10-12 weekly sets. The present study aimed to understand the impact of low-to-very high weekly RET volume on muscular adaptations in trained young males over 6-weeks of RET. Methods: Forty-nine RET-experienced males (n=49) were randomly allocated to a LOW (n=17), moderate (MOD; n=15) or HIGH (n=17) volume group, performing 9, 18 or 27 weekly sets of bicep RET, respectively, for 6-weeks. RET was performed once (LOW) or twice (MOD and HIGH) weekly. Post-exercise protein intake was controlled and dietary intake and external training volume were recorded. Prior-to and following RET, assessments of bicep muscle thickness (MT), isometric and 1RM strength were performed. Results: MT significantly increased in all groups (4.4±7.7%, 8.4±9.9% and 5.6±5.0% for LOW, MOD, HIGH, respectively, P<0.05 for all) as did 1RM strength (7.6±5.6%, 11.2±5.5% and 11.7±4.3% for LOW, MOD, HIGH, respectively, P