The Effects of Exercise Training on Corticospinal System in Overhead Athletes With Shoulder Impingement Syndrome
Condition: Shoulder Impingement Syndrome; Transcranial Magnetic Stimulation; Central Nervous System; Biomechanical Phenomena
MeSH terms: Shoulder Impingement Syndrome; Syndrome; Rotator Cuff Injuries
Study type: Interventional

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.
    


Intervention name(s): Scapula control exercise; scapular strengthening exercise; No intervention
Intervention type(s): Procedure; Procedure; Other
Intervention description(s): 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; 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.; No intervention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Shoulder impingement syndrome; Transcranial magnetic stimulation; Corticospinal system; Scapular control exercise; Kinematics