Functional Training, Lower Limb Stability, Neuromuscular Control
Conditions
Keywords
Single-Leg Deadlift, elastic barbell, inelastic barbell, sports rehabilitation, neuromuscular control
Brief summary
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.
Detailed description
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.
Interventions
DEVICEElastic Barbell
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.
DEVICEInelastic Barbell
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.
Sponsors
Busan University of Foreign Studies
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Crossover Assignment
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Center of Pressure Displacement - Anterior-Posterior (AP) | 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. |
| Center of Pressure Displacement - Medial-Lateral (ML) | 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. |
| Muscle Activation of Lower Limb Muscles (%MVIC) | 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. |
Countries
South Korea
Outcome results
None listed