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NCT Number: NCT07061314

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

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.

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Key information

Conditions

Neuromuscular Control Functional Training Lower Limb Stability

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Busan University of Foreign Studies

Busan, 46234, South Korea

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • No history of musculoskeletal disorders in the past 6 months

At least 1 year of experience in resistance or functional training

Able to perform single-leg deadlift exercise safely

Provided written informed consent

Exclusion criteria

  • History of lower extremity surgery or major musculoskeletal injury within the past year

Current pain or symptoms in the hip, knee, or ankle joints

Neurological, cardiovascular, or balance disorders

Participation in other conflicting research studies within the last 3 months

Inability to maintain single-leg stance for at least 5 seconds

Presence of skin irritation or condition at electrode placement sites

Treatment and study plan

Elastic Barbell

Device

A flexible plastic barbell that creates top-down perturbations during movement. Participants perform single-leg deadlifts using this elastic bar at three different speeds: normal (2 sec), fast (1 sec), and power (as fast as possible). The bar is loaded to 30% of the participant's estimated 1RM.

Inelastic Barbell

Device

A standard rigid steel barbell with no elasticity. Participants perform single-leg deadlifts using this barbell under the same speed conditions and loading parameters as the elastic barbell.

Primary outcomes

  1. Center of Pressure Displacement - Anterior-Posterior (AP)

    Time frame: During single-leg deadlift task (within single session)

    The range of anterior-posterior (AP) sway displacement (in centimeters) will be measured using a force platform (AMTI OR6). Participants perform SLDL under both barbell conditions at three different movement speeds. Lower values indicate greater postural stability.

  2. Center of Pressure Displacement - Medial-Lateral (ML)

    Time frame: During single-leg deadlift task (within single session)

    The range of medial-lateral (ML) sway displacement (in centimeters) will be measured using a force platform (AMTI OR6). The COP variability is analyzed as an indicator of dynamic balance control.

  3. Muscle Activation of Lower Limb Muscles (%MVIC)

    Time frame: During single-leg deadlift task (within single session)

    Surface electromyography (EMG) will be used to measure muscle activation in eight lower limb muscles during single-leg deadlifts under elastic and inelastic barbell conditions at three movement speeds (normal, fast, power). The muscles assessed include gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus, gastrocnemius, and tibialis anterior.

    EMG signals will be processed using RMS and normalized to maximum voluntary isometric contraction (%MVIC). Increased %MVIC indicates higher neuromuscular demand under perturbation.

Sponsors and collaborators

Lead sponsor

Busan University of Foreign Studies

Other

Registry information

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jul 11, 2025
Registry last updated
Jul 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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