Training Volume Increases Or Maintenance Based On Previous Volume: The Effects On Muscular Adaptations In Trained Males

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, while 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 eight weeks. We assessed pre- and post-study thigh region-of-interest fat-free mass (ROI-FFM), anterior thigh muscle thickness (MT) at two sites: proximal (PMT) and distal (DMT) and their sum (ΣMT), 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 post-training (main time effect, p<0.001), (ΔΣMT CON: 1.07cm, G30: 0.76cm, G60: 0.70cm; ΔROI-FFM CON: 1.57kg, G30: 0.47kg, G60: 1.55kg). 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 (174.7kg), than the G30(159.0kg), and G60(149.0kg). Only the G30 group increased RTF at the post-test (CON: 0.13reps, G30: 5.45reps, G60: -0.41reps), (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.