The Effects of Muscle Characteristics on the Control of Shoulder Complex During Functional Movements
The Effects of Muscle Characteristics on the Control of Shoulder Complex During Functional Movements
The movement control of shoulder joint relies not only on the glenohumeral joint, but also
 the critical contributions from scapulothoracic joint. The relating scapula muscle strength,
 scapula mobility and, the most important of all, the capacity of neuromuscular control should
 be integrated into the rehabilitation program for patients with shoulder disorders. With
 regarding to the subacromial impingement syndrome or rotator tendinopathy, the status of
 scapula dyskinesia and dysfunctions were improved significantly after the intervention of
 scapula-emphasized exercise. But there was no study addressed the relationships between
 stiffness of relating muscles and the deficits of scapula movement. The stiffness had been
 shown to serve an important role in functional performance of the corresponding joint. For
 example, the decreased elasticity of supraspinatus muscle was noticed on affected side
 comparing in patients with impingement syndrome.Few studies examined the effects of altered
 muscle stiffness on kinematic performance in shoulder complex. Laudner et al. found that the
 stiffer the latismuss dorsi muscle was, the less upward rotation and posterior tilting, and
 the more internal rotation of scapula during arm elevation was exhibited in asymptomatic
 swimmers. Another study showed that the increased range of external rotation and posterior
 tilt of scapula during arm elevation were associated with the decreased stiffness of
 pectoralis minor. The recent study presented that the electromyographic activities and
 elasticities of middle deltoid, supraspinatus, and infraspinatus muscles correlated
 significantly with the tissue elasticity during shoulder movement in healthy shoulder.
 However, there was no scientific information directly to prove the changes in characteristics
 of rotator cuff function as well as the impacts on kinematic control of shoulder complex.
 Therefore, the aim of this study is to examine the relationship among characteristics of
 muscle properties and kinematic control healthy swimmers.
Inclusion Criteria:

 -  freestyle swimmers with health shoulders

 Exclusion Criteria:

 -  the past or current shoulder pain or disorders are examined by history taking and
 screening tests: shoulder impingement syndrome, instability, bony deformity, trauma,
 nerve injury or entrapment.