Clinical trial NCT07000773: Trapezius Muscle Activation During Bilateral Scapular Retraction and Shoulder External Rotation Under Kinetic Chain and Unstable Surface Conditions
Official title: Trapezius Activation During Bilateral Scapular Retraction With Shoulder External Rotation: The Incorporation of Knetic Chain and Unstable Surface
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Healthy Volunteers
Keywords: scapular muscle activation
Electromyography
Kinetic Chain
Scapular Retraction
Trapezius
Unstable Surface
Lead sponsor: Recep Tayyip Erdogan University
Sponsor class: OTHER
Collaborators: name: Gazi University
First posted: 2025-06-03
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
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.
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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

Primary outcomes:
measure: Upper Trapezius Muscle Activation
timeFrame: Day 1 (during the exercise session)
measure: Middle Trapezius Muscle Activation
timeFrame: Day 1 (during the exercise session)
measure: Lower Trapezius Muscle Activation
timeFrame: Day 1 (during the exercise session)
measure: Muscle Activation Ratios
timeFrame: Day 1 (during the exercise session)
Secondary outcomes:
Other outcomes:
Locations:
city: Ankara
country: Turkey
facility: Gazi University
state: Çankaya
Study officials:
affiliation: Gazi University
name: Gamze Cobanoglu Demirkan, PhD
role: PRINCIPAL_INVESTIGATOR
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