Effect of Shoulder Injury and Fatigue in Biomechanics of Upper Limb During Fastball Pitching in Taiwanese Baseball Pitchers

  • 洪 孟緯

Student thesis: Doctoral Thesis


As overhead movement plays a major role in baseball pitching highly repetitive motion or long-term training or overuse under fatigue is highly related to a risk of dominant shoulder injuries The purpose of this study was to investigate the mechanism of pitching after fatigue had occurred identify the effect of fatigue protocol on the local joint and then conducted a comparison in kinematics kinetics and electromyography (EMG) data between injury and control groups to determine whether there was the significant difference after the fatigue protocol The results showed no significant difference in ball speed and accuracy of pitching between the fatigue tests However there were significant differences in the maximum shoulder external rotation angle in the cocking phase (P = 0 015) the maximum internal rotation angular velocity in the acceleration phase (P = 0 008) and the smaller shoulder abduction angle in the acceleration phase (P = 0 004) after the fatigue protocol Infraspinatus of the muscle activity had a significant difference in the EMG result after the fatigue test (P = 0 003) In spite of the fact that there was no significant difference in the kinetic results (P = 0 060) elbow varus torque still affected baseball fastball pitching To guarantee the maximum performance without sacrificing ball speed and accuracy pitchers would depend on smaller swinging trajectory and the enhancement of rotator cuff to protect their shoulder anterior muscle and the shoulder joint lip Increasing the warm-up project and time and limiting the number of balls pitched in the game and practice were an important way to avoid injury Complete stretching activities and enhancement of the strength of the rotating muscles after pitching were the key to prolonging the pitching career
Date of Award2019
Original languageEnglish
SupervisorLin-Hwa Wang (Supervisor)

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