【論文摘要】Differences in Pitching Biomechanics and Shoulder Function in High School Baseball Pitchers With and Without Scapular Dyskinesis

【論文摘要】肩胛運動障礙與否於高中棒球投手投球生物力學與肩膀功能之差異

陳登翔(Deng-Siang Ting) ； 黃崇舜(Tsun-Shun Huang) ； 翁義軒(Yi-Hsuan Weng) ； 張哲嘉(Che-Chia Chang) ； 蔡鏞申(Yung-Shen Tsai) ； 林居正(Jiu-Jenq Lin)

《物理治療》 46卷2期 (2021/06) Pp. 100-101

https://doi.org/10.6215/FJPT.202106.O08

摘要

Background and Purpose: The impact of scapular dyskinesis on pitching biomechanics and shoulder dysfunction in high school pitchers remains unclear. The purpose of this study was to investigate (1) the influence of scapular dyskinesis on scapular kinematics, scapular muscle activation, shoulder function, and athletic performance in high school baseball pitchers, and (2) the related factors associated with shoulder function and performance. Methods: Thirty-eight high school baseball pitchers were recruited and classified into two groups based on dyskinesis (n = 26) or no dyskinesis (n = 12). They were assessed with the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) scale and clinical measurements of shoulder characteristics, as well as assessment of scapular kinematics, muscle activation, and ball speed during fastball pitching. We analyzed differences in outcomes of clinical measurements, scapular kinematics, muscle activation, KJOC scores, and ball speed between the groups. Furthermore, stepwise multiple linear regressions were used to determine the related factors to KJOC scores. Results: Less scapular external rotation (difference = 6.3-14.4 degrees, p = 0.012), more inferior angle displacement (difference =1.9 cm, p = 0.036), and decreased the upper trapezius activation (difference = 7.1-12.5%, p = 0.019-0.035) were found in pitchers with scapular dyskinesis than in those without dyskinesis. Additionally, more scapular external rotation at ball release and increased the lower trapezius activation during the acceleration phase were significantly associated with higher KJOC scores in the regression model (total R^2 = 0.231). Conclusion: More inferior angle displacement as well as less scapular external rotation and decreased the upper trapezius activation during fastball pitching were found in high school pitchers with scapular dyskinesis. No variables were related to ball speed. Clinical Relevance: Strategy to increase external rotation of the scapula and the lower trapezius muscle activation during pitching may be beneficial to pitcher, especially with scapular dyskinesis.