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

Overview

This study aims to investigate the effects of barbell type (elastic vs. inelastic) and lifting speed on lower limb balance and muscle activation during the Single-Leg Deadlift (SLDL) exercise. Using a randomized crossover design, healthy adults performed SLDL at three different movement speeds while center of pressure (COP) and electromyographic (EMG) responses were measured. The study seeks to determine whether elastic barbells, which create top-down perturbations, enhance neuromuscular control and postural stability more effectively than traditional 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.