A Biomechanical Analysis among Breakingball in Baseball Pitchers with Glenohumeral Internal Rotation Deficit

• Main Authors: Yan-Ting Haung, 黃燕婷
• Other Authors: Pei-Hsi Chou
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/43022084823166575634

碩士 === 高雄醫學大學 === 運動醫學系碩士班 === 105 === Introduction: Baseball is quite popular all over the world. When the pitcher is performing this most dynamic motion, the throwing shoulder is subjected to a considerable load. This performance is tributary to adaption of the shoulder muscles and the joint itself. These adaptions may, however lead specific problems of the throwing shoulder: decreased internal rotation of the glenohumeral joint with compensatory problems of the scapula-stabilizing muscles. And, many studies have shown that glenohumeral internal rotation deficit (GIRD) as risk factor of shoulder and elbow injury. There were some previous biomechanical studies focused on fastball pitching of the GIRD pitchers. But, the breaking ball is also important for them. Purpose: The purpose of this study was to investigate kinematics and kinetics diference between GIRD group and normal group in curveball, slideball and fastball pitching. Method: There were twenty baseball pitchers with glenohumeral internal rotation deficit and twenty baseball pitchers without glenohumeral internal rotation deficit conducted this biomechanical study. Basic information, passive shoulder and elbow range of motion, muscle strength, pitching motion were assessed. Group comparisons were made between pitchers with and without GIRD using independent t tests with significant level set at p<.05. Results: There are twenty-five of eighty-one kinematic parameters and fourteen of thirty-three kinetic parameters in curveball pitching have significantly statistical difference. There are fifteen of eighty-one kinematic parameters and fourteen of thirty-three kinetic parameters in slideball pitching have significantly statistical difference. There are thirty-two of eighty-one kinematic parameters and twenty of thirty-three kinetic parameters in fastball pitching have significantly statistical difference. Conclusion: The proper training program of the flexor-pronator muscles of forearm and the scapula dynamic stabilized muscles (eg, trapezius, rhomboid, serratus anterior) may help to enhance pitching performance of the pitchers with GIRD.