Does Performing Partial Repetitions Beyond Momentary Failure Enhance Muscle Hypertrophy in Volume-Load-Equated Calf-Raise Resistance Training?

The aim of this study was to determine whether extending traditional calf-raise resistance training sets with partial-range-of-motion (ROM) repetitions in the more dorsiflexed ROM enhances muscular hypertrophy. Sixteen untrained men (25.0±1.7y) completed 10 weeks of unilateral standing calf-raise training (2×/wk) in a within-subject design: one leg performed traditional 10-14RM sets to full-ROM momentary failure (MF; 4-6 sets/session) and the other leg performed half as many sets to full-ROM failure followed by partial-ROM repetitions to a second failure in the more dorsiflexed ROM (PBF; 2-3 sets/session). Total volume-load was equated between conditions; repetitions were counted the same way regardless of the ROM. Muscle hypertrophy was assessed as changes in muscle thicknesses of the gastrocnemius medialis and lateralis via B-mode ultrasound imaging. After training, both MF and PBF elicited equivalent (equivalence test P-values <0.05) changes in muscle thickness (averaged muscle thicknesses; MF:8%, PBF:8%). Per-set analyses, however, revealed greater efficiency (P<0.05) with PBF (0.16%) in comparison to MF (0.08%). In conclusion, adding "longer-length" partial-ROM repetitions to failure beyond full-ROM failure (PBF) permits a greater accumulation of volume-load per set and elicit greater changes in muscle size on a per-set basis analysis. Under volume-load-equated conditions, PBF and training to full-ROM failure (MF) seem to evoke similar changes in gastrocnemius thickness after 10 weeks of unilateral standing calf-raise training in untrained young men.