The purpose of this study is to investigate muscle activations of the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), latissimus dorsi (LD), and muscle balance ratios of UT/LT, UT/SA I in overhead athletes with SD via KC-based exercise in water and on land. KC-based exercises including the movement patterns of Ai Chi which consist of shoulder flexion/ extension, horizontal abduction/ adduction, internal and external rotation, scapular protraction/retraction combined with spinal rotation.
Scapular dyskinesis (SD) is common in overhead athletes and negatively influence the athletes' performance, increasing the risk of shoulder injury. The kinetic chain (KC) exercises for SD rehabilitation that emphasize importance of core strength and scapula stability during skillful performance. Ai Chi, the aquatic exercises performed in functional positions, which are adequate for power transfer of KC. This study will investigate the effect of KC-based water exercises, Ai Chi, on scapular muscles in overhead athletes with SD.