Muscle Fatigue and Scapular Sensorimotor System

Study Overview
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Brief Summary
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The aims of this study are to investigate the effects of scapular muscle fatigue on scapular joint position sense and neuromuscular performance (scapular muscle strength, the kinematics data and muscle activity of shoulder during scaption (arm elevation in the scapular plane)). The investigators hypothesize that scapular muscle fatigue would increase scapular reposition error and affect neuromuscular performance of the scapular during scaption.

Official Title
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Muscle Fatigue and Scapular Sensorimotor System

Conditions
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Muscle; Fatigue

Intervention / Treatment
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* Other: muscle fatigue


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: no shoulder, cervical, and thoracic spine pain within six months negative for subacromial impingement test normal range of motion of glenohumeral joint Exclusion Criteria: history of dislocation, fracture, or surgery of shoulder joint history of central nervous system disorder, rheumatoid arthritis, shoulder osteoarthritis, or cervical radiculopathy

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: muscle fatigue|Modified push-up plus exercise: the participants first supported by both knees and the single elbow, and then performed sustained scapular protraction for three minutes with ten repetitions in males and two minutes with five repetitions in females with forty-five seconds rest between.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Scapular Proprioception | Test the ability of active re-position the scapula from neutral to 90% range of protraction, and elevation. | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 
| Change From Baseline in Muscle Activation During Scapular Proprioception | Test the ability of muscle activation (upper trapezius, lower trapezius, and serratus anterior) during active re-position the scapula from neutral to 90% range of protraction, and elevation. Muscle activation during active re-position would divide into muscle activation during maximum voluntary isometric contraction (MVIC), present in percent. | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Scapular Muscle Strength | use dynamometer to detect the force of maximum isometric voluntary contraction of upper trapezius, lower trapezius and serratus anterior | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 
| Change From Baseline in Shoulder Kinematics Data During Shoulder Elevation in the Scapular Plane | use Liberty to detect the motion of spine, humerus, and scapula during shoulder elevation in the scapular plane (scaption) | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 
| Change From Baseline in Scapular Muscle Activity During Shoulder Elevation in the Scapular Plane | Test the ability of muscle activity (upper trapezius, lower trapezius, and serratus anterior) during shoulder elevation in the scapular plane (scaption). Muscle activation during scaption would divide into muscle activation during maximum voluntary isometric contraction (MVIC), present in percent. | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 
| Change From Baseline in Scapular Muscle Recruitment Timing During Arm Elevation in Scapular Plane | Test the ability of muscle onset timing (upper trapezius, lower trapezius, and serratus anterior) during shoulder elevation in the scapular plane (scaption). Onset timing was determined by EMG signals bigger than resting signals plus 3 times standard deviations. Origin was set at onset of kinematics data of glenohumeral joint. | through fatigue intervention completion, an average of 20 minutes in female subjects and 40 minutes in male subjects | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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sensorimotor system, scapular joint position sense, fatigue