Training Volume Increases or Maintenance Based on Previous Volume: The Effects on Muscular Adaptations in Trained Males

Abstract

This study investigated the effects of increasing previous resistance training (RT) weekly set volume by 30% (G30) and 60% (G60) on muscle hypertrophy and strength. Fifty-five resistance-trained men were randomly allocated to the experimental groups, whereas 29 completed the study, as follows: control group (CON): n = 10, G30: n = 10, and G60: n = 9. Participants underwent a lower body RT program twice a week for 8 wk. We assessed pre- and poststudy thigh region-of-interest fat-free mass (ROIFFM), anterior thigh muscle thickness (MT) at two sites: proximal (PMT) and distal (DMT) and their sum (RMT), one-repetition maximum (1RM), and strength-endurance via repetitions to failure (RTF) at 70% of 1RM. ROI-FFM and MT demonstrated a significant increase from pre- to posttraining (main time effect, P < 0.001) (DRMT CON: 1.07 cm, G30: 0.76 cm, and G60: 0.70 cm; DROIFFM CON: 1.57 kg, G30: 0.47 kg, and G60: 1.55 kg). All groups increased back squat 1RM (P < 0.0001). However, the main group effect (P < 0.0268) indicated that the CON group showcased a greater overall 1RM (174.7 kg), than the G30 (159.0 kg) and G60 (149.0 kg). Only the G30 group increased RTF at the posttest (CON: 0.13 reps, G30: 5.45 reps, and G60: -0.41 reps) (P < 0.0263). Our findings suggest that trained males can experience significant muscle growth and strength adaptations while maintaining their previous weekly set number above a certain weekly set volume threshold.