Throwing Kinematics and Physical Characteristics in Youth Baseball Players with and without Medial Elbow Pain

• Main Authors: Ting-Yu Wu, 吳亭諭
• Other Authors: Yung-Shen Tsai
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/87996394798673276256

碩士 === 國立成功大學 === 物理治療研究所 === 96 === Background and purpose Medial elbow injuries are common in youth baseball players. Repetitive throwing movement places excessive valgus stress over the immature elbow that may cause medial elbow injury. Previous studies have investigated the relationships between throwing kinematics and elbow valgus stress in healthy adult throwers. No research compares the differences in throwing kinematics and physical characteristics between youth baseball players with and without medial elbow pain. The purpose of this study was to investigate throwing kinematics and physical characteristics (muscle strength, flexibility and balance) in youth baseball players with and without medial elbow pain. Methods Fifteen players with previous medial elbow pain and 15 healthy players participated in this study. Age, height, and weight were matched for the two groups. Throwing kinematics were recorded by an electromagnetic motion analysis system. Foot switch was used for determining foot off and foot strike. Ball speed was recorded with a sports radar gun. Isometric strength of trunk, hip, and shoulder was measured using a torque sensor attached to a custom device. Elbow, shoulder, and hip flexibility were measured with a goniometer and a tape measure. Single leg standing balance with eyes open and eyes closed was assessed with a force plate. Paired-t tests were used to compare the differences in throwing kinematics, muscle strength, flexibility, and single leg standing balance between the two groups. Results Elbow pain group demonstrated less elbow flexion angle at maximum shoulder external rotation in late cocking phase and had more trunk lateral tilt at ball release compared to the healthy group. No significant differences were found in isometric strength of trunk, hip, and shoulder between the two groups. Elbow pain group had less passive range of motion in shoulder external rotation compared to the healthy group. In the elbow pain group, elbow flexion angle and total elbow range of motion were less in the throwing arm compared to the non-throwing arm. Less flexibility was observed in the lead hip compared to the non-lead hip in the elbow pain group. There were no significant differences in single leg standing balance between the two groups. Conclusions Differences in throwing kinematics and flexibility were found between youth baseball players with and without previous medial elbow pain. Clinicians and baseball coaches should pay attention to these risk factors in addition to their age, height, weight, and overuse for protecting these players.