Healthy Volunteers
Conditions
Keywords
scapular muscle activation, Electromyography, Kinetic Chain, Scapular Retraction, Trapezius, Unstable Surface
Brief summary
This study aims to investigate the effects of performing the Bilateral Scapular Retraction with Shoulder External Rotation (BSR-SER) exercise under kinetic chain involvement and unstable surface conditions on trapezius muscle activation. Surface electromyography (EMG) will be used to assess the activity levels of the upper, middle, and lower trapezius muscles. The goal is to determine whether integrating kinetic chain elements and instability can optimize muscle activation patterns in healthy individuals during a commonly used scapular rehabilitation exercise.
Detailed description
Maintaining muscular balance among the scapular stabilizers is crucial for optimal shoulder function. The Bilateral Scapular Retraction with Shoulder External Rotation (BSR-SER) exercise is frequently used in clinical rehabilitation to activate the lower trapezius while minimizing upper trapezius activity. Although this exercise is widely practiced, the effects of performing it under kinetic chain conditions (such as squat and lunge positions) and on an unstable surface have not been thoroughly explored. This study will examine how adding kinetic chain involvement and instability influences the electromyographic activity of the upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) muscles during the BSR-SER exercise. Twenty healthy participants will perform the exercise in various lower extremity positions (standing, squat, lunge) and on both stable and unstable surfaces using a BOSU® ball. EMG data will be collected using a wireless surface EMG system and analyzed in terms of percentage of maximal voluntary isometric contraction (%MVIC). The results of this study may provide valuable insights into the optimization of scapular stabilization exercises and guide clinicians in designing more effective shoulder rehabilitation programs by incorporating kinetic chain principles and unstable surfaces.
Interventions
BEHAVIORALBilateral Scapular Retraction with Shoulder External Rotation (BSR-SER) Exercise
Participants perform the Bilateral Scapular Retraction with Shoulder External Rotation (BSR-SER) exercise using a resistance band. The exercise is conducted under various conditions including stable and unstable surfaces (using BOSU® balance trainer) and in three different lower limb positions: standing, lunge, and squat. Each condition is randomized, and participants complete all conditions in a crossover design. The intervention aims to evaluate trapezius muscle activation patterns during these exercises using surface electromyography (EMG).
Sponsors
Gazi University
Recep Tayyip Erdogan University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
This is a randomized crossover study where each participant performs the Bilateral Scapular Retraction with Shoulder External Rotation (BSR-SER) exercise under multiple conditions. The exercise is performed on both stable and unstable surfaces and in different lower extremity positions (standing, lunge, and squat). Each participant acts as their own control by completing all exercise conditions in a randomized order. Electromyographic (EMG) activity of the trapezius muscles is measured during each condition to assess muscle activation patterns.
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Age between 18 and 35 years * Body Mass Index (BMI) less than 30 kg/m²
Exclusion criteria
* Engaging in more than 6 hours per week of overhead sports or upper extremity strength training * History of surgery in the spine, lower extremities, or upper extremities * Experiencing pain in these regions within the past 6 weeks * Having a rheumatologic, systemic, or metabolic disease
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Upper Trapezius Muscle Activation | Day 1 (during the exercise session) | Surface electromyography (EMG) will measure the muscle activation level of the upper trapezius during the stationary phase of the BSR-SER exercise under various conditions. The activation will be normalized as a percentage of maximal voluntary isometric contraction (%MVIC). |
| Middle Trapezius Muscle Activation | Day 1 (during the exercise session) | Surface EMG will measure the muscle activation level of the middle trapezius muscle during the stationary phase of the BSR-SER exercise under different surface and lower limb position conditions. Activation levels will be expressed as %MVIC. |
| Lower Trapezius Muscle Activation | Day 1 (during the exercise session) | Surface EMG will measure the muscle activation of the lower trapezius during the stationary phase of the BSR-SER exercise. Muscle activity will be normalized to %MVIC. |
| Muscle Activation Ratios | Day 1 (during the exercise session) | Ratios of muscle activation between the upper, middle, and lower trapezius muscles will be calculated to assess balance of muscle recruitment during exercise. |
Countries
Turkey (Türkiye)
Outcome results
None listed