Effects Of Unilateral Resistance Training On Muscular Strength, Power, And Measures Of Core Stability In Trained Individuals

Abstract

PURPOSE: This study examined the effects of unilateral resistance training on lower body muscular strength and power, and measures of core stability in resistance-trained college students. METHODS: Participants (N=22) underwent either 10 sessions of lower body unilateral (URT) or bilateral (BRT) resistance training on three non-consecutive days per week for three weeks. Training sessions consisted of three sets of five repetitions at 80% 1-RM for each exercise. BRT exercises included the barbell back squat, deadlift, and weighted jump squat. URT exercises included the Bulgarian split squat, single leg of Romanian deadlift, and single leg weighted jump squat. Outcome measures were a one repetition maximum (1-RM) leg press for lower body strength, standing vertical jump (VJ) for lower body power, and double leg lowering (DLL), hip abduction isometric strength (HAIS), and Sorensen (SOR) tests for core stability. RESULTS: Training elicited a positive main effect of time for all variables (p < 0.05). Both groups improved pre to post training in 1-RM (297±95.4 to 373±114 kg), VJ (56.5±15.0 to 62.2±10.8 cm), DLL (33.9±14.9 to 43.6±13.2 deg), HAIS (29.6±8.86 to 32.6±10.1 kg), and SOR (91.4±33.1 to 112±36.7 sec). The magnitude of change was similar between groups for all variables except HAIS, in which the UL group demonstrated significantly (p=0.0155) greater improvement (14.3% vs. 5.3%). However, the effect size was larger in UL for all variables except VJ (Cohen’s d = 0.86 vs. 0.61 for 1-RM, 0.92 vs. 0.55 for DLL, 0.64 vs. 0.19 for HAIS, 0.90 vs. 0.36 for SOR). CONCLUSIONS: Relative to bilateral training, unilateral resistance training produced similar improvements in measures of lower body strength and power in trained subjects. Additionally, these data suggest that unilateral training may potentially offer the benefit of enhanced core stability.