Does increasing the resistance-training volume lead to greater gains? The effects of weekly set progressions on muscular adaptations in females

We investigated the effect of increasing the number of sets per week every fortnight versus performing a constant set volume on muscular adaptations over 12 weeks. Thirty females (RT experience 2.1 ± 1.0 years) were randomly assigned to a constant group (CG, n = 9) that performed 22 sets per week, a two-set progression group (2SG, n = 11), or a four-set progression group (4SG, n = 10). Forty-five degree leg press one-repetition maximum (1RM), vastus lateralis cross-sectional area (VL-CSA), and the sum of proximal, middle and distal lateral thigh muscle thickness (∑MT) were assessed at baseline and after the intervention. We observed that the 4SG and 2SG conditions showed greater improvements in 1RM than the CG (p < 0.001, p = 0.032, respectively), with no differences between 4SG and 2SG (p = 0.118). Regarding VL-CSA, the 4SG group showed greater increases than the CG (p = 0.029) but not than the 2SG (p = 0.263), whereas no differences between the 2SG and CG (p = 0.443) were observed. There were no differences between groups for ∑MT (p = 0.783). While all groups demonstrated improvements in the measured outcomes, our findings suggest that increasing weekly sets may offer additional benefits for 1RM and vastus lateralis cross-sectional area. However, no additional benefits were observed for ∑MT.