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

Summary

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.

Conditions

• Shoulder Impingement Syndrome
• Transcranial Magnetic Stimulation
• Central Nervous System
• Biomechanical Phenomena

Interventions

PROCEDURE

Scapula control exercise

To perform arm elevation in the scapular plane, subjects will be first asked to correct scapular resting posture in sitting with EMG biofeedback. Then the subjects will be instructed to do elevation in the scapular plane, side lying external rotation and dynamic hug plus with control of the scapula by EMG feedback and verbal cues

PROCEDURE

scapular strengthening exercise

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

OTHER

No intervention

No intervention

Sponsors & Collaborators

• National Yang Ming Chiao Tung University

  lead OTHER

Principal Investigators

• Yin-Liang Lin, PhD · National Yang Ming Chiao Tung University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

20 Years

Max Age

40 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-10-22

Primary Completion

2021-02-28

Completion

2021-02-28

Countries

• Taiwan

Study Locations