Alterations in Shoulder Kinematics(SUMMERY) Patients with shoulder impingement exhibits a decrease in scapular upward rotation at 31-120(phase1 31-60, phase

2 61-90, phase 3 91-120). It has also been noted that there was an increase in anterior tipping of the scapula in phase 3. Studies show through Muscle electromyographic Activity that the upper trapezius and lower trapezius showed an increase in activity in the final 2 phases but the changes of the upper trapezius was only visible with a 4.6kg load condition. The serratus anterior muscle demonstrated a decrease in activity with patients with shoulder impingement syndrome across all loads and phases.

Functional Anatomy of the Shoulder Complex(SUMMERY) The articular surfaces of the glenohumeral joint contribute little to stability, and the dynamic relationships of the joint are largely the function of the soft tissue elements. The glenohumeral capsule, coracohumeral and glenohumeral ligaments, and the rotator cuff mechanism have significant and precise roles in maintaining joint stability and in influencing the range and direction of movement. The clavicular joints influence the ROM and the contribution of the scapula to total arm movement. The scapulothoracic component of upper limb movement is the product of sternoclavicular and acromioclavicular joint mobility. The major structures influencing the clavicular joint mechanisms are the coracoclavicular and costoclavicular ligaments and the articular disk of the sternoclavicular joint. The clavicle also plays a vital role in the transfer of forces to the axial skeleton and the suspension of the dependent upper limb. During elevation of the upper limb, the interactive forces of the flexor and abductor muscles of the humerus and the infraspinatus muscles create a vital mechanical force couple that maintains and controls the glenohumeral relationship. Because the articular surfaces of the joints of the shoulder complex contribute little to the stability of the joint mechanism, the ligaments and periarticular structures are of prime importance in maintaining joint relationships and permitting normal function.

The Role of the Scapula in the Rehabilitation of Shoulder Injuries The shoulder must be considered a kinetic chain made up of several joints. The normal function of the scapula and surrounding musculature is vital to the overall normal function of the shoulder. Rotator cuff strengthening has been an obvious treatment for various pathologies. Since the origins of the rotator cuff muscles arise from the scapula, an effective. exercise regime for rehabilitation should include improving the strength and function of the muscles that control the position of the scapula. Weakness of these anchoring muscles may lead to altered biomechanics of the glenohumeral joint, with resultant excessive stress imparted to the rotator cuff and anterior capsule. Advancements in the knowledge of biomechanics and electromyographic patterns of the shoulder have allowed us to develop strengthening exercises that maximally strengthen these "anchor" muscles.

Role of Scapular Stabilizers The shoulder must be considered a kinematic chain made up of several joints. The function of the scapula and surrounding musculature is vital to the overall normal function of the shoulder. Rotator cuff strengthening has been an obvious treatment for various pathologies. Since the origins of the rotator cuff muscles arise from the scapula, an effective exercise regime for rehabilitation should include improving strength and function of the muscles that control the position of the scapula. Weakness of these anchoring muscles may lead to altered biomechanics of the glenohumeral joint with resultant excessive stress imparted to the rotator cuff and anterior capsule. Advancement in the knowledge of biomechanics and electromyographic patterns of the shoulder has allowed us to develop strengthening exercises that maximally strengthen these "anchor" muscles. The three basic activities to remember when designing a scapular strengthening program are scapular pinches, shrugs, and punches. The choice and intensity of specific exercises are determined by pain and associated pathology.

Shoulder Muscle Imbalance and Subacromial Impingement Syndrome in Overhead Athletes In summary, functional impingement may be associated with muscle imbalance; therefore, careful examination of flexibility and strength of important muscles about the shoulder complex is vital to understanding the root cause of impingement and prescribing effective treatment. Jandas approach to muscle imbalance suggests a possible neuromuscular component to functional impingement due to the predisposition of certain muscles to be tight or weak. The literature substantiates that imbalances in the glenohumeral and scapulothoracic musculature are present in patients with subacromial impingement. Most believe that functional impingement is best managed with conservative treatment. While structural impingement sometimes requires surgical intervention, surgery for functional impingement may make patients worse. Successful treatment of functional impingement related to muscle imbalance is often accomplished by addressing the cause of the problem rather than symptomatic treatment of the pain. By understanding muscle imbalances associated with functional impingement, physical therapists can prescribe appropriate exercises for both treatment and prevention

The impact of subacromial impingement syndrome A difference may exist in %MVC(EMG) for upper trapezius and onset of muscle recruitment for lower trapezius between people with SIS and healthy controls. Evidence did not exist or was inconsistent to support differences in other muscles. The variation in results may be typical of the range of patients presenting with SIS or may be because some studies were inadequately powered to detect true differences. Methodological and demographic heterogeneity may also be a source of variation between studies.

Scapular and rotator cuff muscle activity during arm elevation: A review of normal function and alterations with shoulder impingement Despite nearly 70 years of research data on shoulder function and dysfunction, there is still much yet to understand regarding the complex interactions of multiple muscles to produce the coordinated 3-D motion of the shoulder complex. The quantitative capabilities of the muscles in 3-D, across varying shoulder positions, and in reverse action, require further investigation. In addition, the motor control of coordinated shoulder function remains minimally investigated. Several clinical trials have demonstrated significant positive effects of shoulder exercises in alleviating shoulder impingement symptoms57-63. Continued refinement of shoulder impingement exercise approaches holds promise for further gains in rehabilitation effectiveness for these patients.