The Effects of Exercise Training on Corticospinal System in Overhead Athletes With Shoulder Impingement Syndrome

National Yang Ming Chiao Tung University

Status: Completed

Conditions: Transcranial Magnetic Stimulation; Shoulder Impingement Syndrome; Biomechanical Phenomena; Central Nervous System

Treatments: Procedure: Scapula control exercise; Other: No intervention; Procedure: scapular strengthening exercise

Study type: Interventional

Funder types: Other

Identifiers

NCT04014491

YM108043F

Details and patient eligibility

About

Shoulder impingement syndrome is the most common shoulder disorder in overhead athletes. It describes a mechanical compression of subacromial bursa and rotator cuff tendons during arm movement, which results in pain and injuries. Most of previous studies focus on investigating motor performance in individuals with shoulder impingement syndrome and found altered scapular kinematics and muscle activation may contribute to the impingement. Recently few studies found changes in the central nervous system, decreases in corticospinal excitability and increases in inhibition in scapular muscles, by using transcranial magnetic stimulation (TMS). Although more studies are still needed to investigate the changes in central nervous system in the individuals with impingement syndrome, the changes in central nervous system are believed to be associated with the deficits of impingement syndrome. However, the exercise protocols for the impingement syndrome are usually designed to restore scapular kinematics and muscle activation, including scapular muscle strengthening exercise and scapular control exercise. To our knowledge, no study has investigated whether these exercise protocols can reverse these changes in the corticospinal system. The objectives of this proposal are to understand neuromuscular and neurophysiological mechanisms of the scapula-focused exercise protocols to improve the effectiveness of treatment. The study aims to investigate the effects of scapular muscle strengthening training and scapular control training on the scapular kinematics, muscle activation and corticospinal system. The study also aims to investigate whether any other cortical mechanisms are also affected by the shoulder impingement syndrome. We will recruit 70 overhead athletes with shoulder impingement syndrome and 22 healthy control athletes. Subjects with shoulder impingement syndrome will randomly receive either scapular muscle strengthening or scapular control training. When performing the exercise, subjects in the scapular control training group will receive electromyography feedback and cues but those in the strengthening training group will not. Immediate effects of these two training protocols on scapular kinematics, muscle activation, and neurophysiological measures will be tested before and after the training. Neurophysiological measures will be tested by TMS, including corticospinal excitability, cortical inhibition, intracortical inhibition, and intracortical facilitation.

Enrollment: 65 patients

Sex: All

Ages: 20 to 40 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria: (patients of shoulder impingement)

1. Practice overhead exercise more than six hours a week,
2. Aged 20 to 40 years old,
3. Have shoulder pain localized at the anterior or lateral aspect of shoulder more than two weeks,
4. Have obvious medial border prominence of the scapula at 90° of arm elevation,
5. Have shoulder impingement syndrome, which is confirmed by having at least two of the following: (a) positive Neer test, (b) positive Hawkins sign, (c) positive empty can test, (d) positive resisted external rotation test, and (e) tenderness of the rotator cuff tendons

Inclusion Criteria: (healthy subjects)

1. Practice overhead exercise more than six hours a week,
2. Aged 20 to 40 years old,
3. Not have a history of shoulder or neck pain or injury.

Exclusion Criteria (patients of shoulder impingement and healthy subjects)

1. Have a history of dislocation, fracture, or surgery of upper extremity,
2. A history of direct contact injury to the neck or upper extremities within the past 12 months,
3. A concussion within the past 12 months or a history of three or more concussions,
4. Brain injury and neurological impairment,
5. History of frequent headache or dizziness,
6. Contraindications to the use of TMS, assessed with a safety screening questionnaire, including pregnancy, history of seizure, epilepsy and syncope, having cochlear implant, having medal implant and taking anti-depressant medication.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

---

65 participants in 3 patient groups

Scapula control exercise

Experimental group

Description:

Subjects will perform three exercises with EMG biofeedback and verbal cues. Three exercises are elevation in scapular plane, sidelying external rotation and dynamic hug plus

Treatment:

Procedure: Scapula control exercise

Scapula strengthening exercise

Experimental group

Description:

The subjects in the scapular strengthening group will be asked to perform the three exercises the same as scapula control exercise group and with the same number of trials but without any EMG biofeedback and oral cues of movement or posture correction.

Treatment:

Procedure: scapular strengthening exercise

Healthy subject group

Other group

Description:

Healthy subjects will be included to compare the differences in corticospinal system between healthy subjects and subjects with shoulder impingement syndrome, so this group will not receive any treatment.

Treatment:

Other: No intervention