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

May 20, 2021 updated by: National Yang Ming University

The Effects of Scapular Control and Strengthening Training on Neuromuscular Control and Corticospinal System in Overhead Athletes With Shoulder Impingement Syndrome

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.

Study Overview

Study Type

Interventional

Enrollment (Actual)

65

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Taipei, Taiwan, 112
        • Yin-Liang Lin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 40 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Scapula control exercise
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
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
Experimental: Scapula strengthening exercise
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.
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: Healthy subject group
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.
No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Neurophysiological measures - Active motor threshold
Time Frame: Immediately after the intervention
Active motor threshold (AMT) will be described with the percentage (%) of maximum stimulator output (MSO).
Immediately after the intervention
Neurophysiological measures - Motor evoked potential
Time Frame: Immediately after the intervention
Motor evoked potential (MEP) will be described with millivolt (mV).
Immediately after the intervention
Neurophysiological measures - Cortical silent period
Time Frame: Immediately after the intervention
Cortical silent period (CSP) will be measured with millisecond (ms).
Immediately after the intervention
Neurophysiological measures - Short interval cortical inhibition
Time Frame: Immediately after the intervention
Short interval cortical inhibition (SICI) will be defined as percentage (%) of conditioning responses vs testing responses while the inter-stimulus interval is below 5 ms
Immediately after the intervention
Neurophysiological measures - Intra-cortical facilitation
Time Frame: Immediately after the intervention
Intra-cortical facilitation (ICF) will be defined as percentage (%) of conditioning responses vs testing responses while the inter-stimulus interval is above 5 ms
Immediately after the intervention

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Scapular kinematics
Time Frame: Immediately after the intervention
Scapular kinematics, including anterior/posterior tilt, upward/downward rotation, and internal/external rotation in scapula plan elevation at 30°, 60°, 90°, and 120°, will be calculated and will be described with degree (°).
Immediately after the intervention
Scapular muscles activation
Time Frame: Immediately after the intervention
The root mean square of electromyography (EMG) data of the upper trapezius, lower trapezius, and serratus anterior will be normalized by the maximum voluntary contraction amplitude (percentage of maximal voluntary contraction, %) and calculated over three 30° increments of motion during arm elevation from 30° to 120°, including 30° - 60°, 60° - 90°, and 90° - 120°
Immediately after the intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Yin-Liang Lin, PhD, National Yang Ming University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 22, 2019

Primary Completion (Actual)

February 28, 2021

Study Completion (Actual)

February 28, 2021

Study Registration Dates

First Submitted

July 1, 2019

First Submitted That Met QC Criteria

July 9, 2019

First Posted (Actual)

July 10, 2019

Study Record Updates

Last Update Posted (Actual)

May 24, 2021

Last Update Submitted That Met QC Criteria

May 20, 2021

Last Verified

May 1, 2021

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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