The Effects of Exercise Training on Shoulder Neuromuscular Control

Dynamic control of the rotator cuff muscles plays an important role in stabilizing the shoulder during motion. Impairment in the neuromuscular control of these muscles may to lead to injury and pain. Rehabilitation programs have moderate success in decreasing pain and improving shoulder function. While most of these programs target the rotator cuff, it is still unknown if they serve to improve the neuromuscular control of the rotator cuff muscles. The rehabilitation may induce neurological and physiologic changes in neuromuscular structures and thus alter the neuromuscular control of the entire shoulder complex. Kinematics and electromyographic (EMG) activities have been widely used to study neuromuscular control. However, corticospinal excitability, which has been widely examined in the patients with neurological disorders, provides a more detailed account of central control from the primary motor cortex through the spinal cord to the muscles. This assessment of neuromuscular control will serve to illuminate the ability of the shoulder muscles to handle the stress from activities such as overhead sports activities and carrying or lifting heavy objects. This approach could be used to help design efficient training program for athletes and effective rehabilitation program for patients with shoulder injuries. The purpose of the proposed study is to investigate the effect of exercise treatment effect on the proprioception, kinematics, EMG and corticospinal excitability of shoulder muscles, including the deltoid and rotator cuff muscles.