肩痛症狀壘球選手肩部關節位置覺無肩痛選手之比較: 個案報告

Overhead throwing is a fast movement which requires extreme range of motion at shoulder complex. Proprioception plays an important role to maintain joint stability and to prevent further injury. Recent studies suggested that the active reposition acuity reflects the degree of joint position sense deficit. However, they are limited in measuring single joint motion in single plane. Additionally, few studies examined the association between shoulder symptoms and active reposition acuity in overhead throwing athletes. The purpose of this study was to investigate the shoulder joint position sense in softball players with and without shoulder pain. Method: Two softball players (1 with and 1 without shoulder pain) were recruited from our school team. We used electromagnetic tracking device to collect data in arm-cock and ball-release positions. We compared the active reposition acuity between two participants by calculating absolute error and three dimensional variable error. Result and Discussion: Participant with shoulder pain had significantly decreased acuity than that in participant without shoulder pain, especially internal rotation and horizontal abduction in glenohumeral joint. Compared with ball-release position, it is possible that arm-cock position involved more soft tissue in end range and compressed subacromial space. Therefore, possible causes of shoulder pain might influence the input of proprioception. Conclusion: Shoulder joint position sense decreased in the softball player with shoulder pain. This might decrease the stability of shoulder complex and affect the performance of the athlete.