ABSTRACT
In previous studies researchers have reported that the position of the scapula plays a critical role in achieving the appropriate upper-extremity function and proper posture (Kibler, 1998; Voight and Thomson, 2000). Kibler (1998) has reported that an abnormal position of the scapula may decrease the normal function of shoulder. The kinetic chain of shoulder girdle function and scapular position has been attributed to muscular connections between the spine, scapula, clavicle, and humerus. Since the scapula provides a stable base for glenohumeral movements, it seems reasonable to expect that normal pattern of glenohumeral rhythm may be affected if the position of the scapula is altered or muscles become weak or fatigued (Voight and Thomson, 2000). Shoulder pathology and abnormal scapular motion may be linked to imbalanced muscle activity rather than global weakness of scapulothoracic muscles (Warner et al., 1992). In this regard Voight and Thomson (2000) believed that when shoulder function is inefficient, it can not only result in decreased neuromuscular performance but also may predispose the individual to shoulder injury. It seems that insufficient stability of the scapula may result in significant external loading and strain on the shoulder joint.
