Comparison of Lower Limb COP and Muscle Activation During Single-Leg Deadlift Using Elastic and Inelastic Barbells

This randomized clinical trial examines how barbell type and movement speed affect lower limb stability and muscle activation during Single-Leg Deadlift (SLDL) exercises. The intervention compares elastic barbells-designed to generate upper-limb-initiated dynamic perturbations-to conventional inelastic barbells. Twenty-seven healthy adults with prior resistance training experience participated in the study. All participants performed SLDL using both barbell types across three speeds: normal (2 seconds), fast (1 second), and power (as fast as possible). Center of Pressure (COP) data were recorded using a force platform to assess anterior-posterior (AP) and medial-lateral (ML) sway. Surface electromyography (EMG) was collected from eight lower limb muscles to evaluate neuromuscular responses. Data were analyzed using two-way repeated measures ANOVA. The findings revealed that elastic barbells significantly reduced COP displacement and increased activation in the gluteus medius, biceps femoris, semitendinosus, and gastrocnemius muscles-particularly at high movement speeds. These results suggest that elastic barbells may improve dynamic stability and neuromuscular coordination, offering potential applications in sports rehabilitation and unilateral training programs.