Effects of Different Weekly Set Progressions on Muscular Adaptations in Trained Males: Is there a Dose-Response Effect?

Abstract

ABSTRACT Purpose This study investigated the effect of progressively adding sets for the lower- limb every two weeks versus performing a constant set volume in resistance-trained males. Methods Thirty-one resistance-trained males (age 24.4 ± 2.9 years; height 175.5 ± 6.5 cm; body mass 80.1 ± 9.4 kg; body fat 14.4 ± 3.1%; resistance training [RT] experience 5.1 ± 2.2 years; one repetition maximum (1-RM) barbell back squat:body mass ratio 1.7 ± 0.1 a.u.) were randomly allocated into a Constant Group (CG, n = 10), a four sets progression group (4SG, n = 10) or a six sets progression group (6SG, n = 11). After a 2-week washout period and another 2-week familiarization period, participants performed a lower-limb training program twice a week for 12 weeks. Maximum dynamic strength (1-RM) in the barbell back squat, vastus lateralis cross-sectional area (CSA), and the sum of lateral thigh muscle thickness (∑MT) at 30, 50 and 70% of the femur length were assessed at baseline and after the 12-week training program. Results Regarding 1-RM, multiple comparisons revealed that 6SG elicited higher muscle strength gains than 4SG (p = 0.002) and CG (p < 0.0001), and 4SG had greater improvements than CG (p = 0.023). CSA and ∑MT showed no between-group differences (p = 0.067 and p = 0.076, respectively). However, an inspection of 95% confidence intervals suggests a potential dose-response relationship, with results appearing to plateau in the higher volume conditions. Conclusions Our results suggest that progressively adding four or six sets per week every two weeks elicited greater lower-limb strength in resistance-trained individuals over a 12-week training period. While our findings indicate a possible small benefit for higher volume conditions regarding hypertrophic adaptations in this population, the limited certainty of our findings warrants caution.