Recent studies focused on the biomechanics of the pitching have exclusively studied professionals, whereas there is little information on amateur pitchers. Notably, amateur pitchers with improper techniques may result in suboptimal performance and can potentially lead to injury. The present study was aimed to compare the kinematics of the upper extremity during the action of baseball pitching between amateur and professional players. Eighteen subjects (including 8 amateur with 0.9 years mean pitching period, and 10 professional pitchers with 6.7 years mean pitching period) were recruited. Ten kinematic parameters for different instances and phases of pitching cycle were calculated to examine
differences between professionals and amateurs. Our results showed four of the ten kinematic parameters with significant difference between these two groups. The parameters included elbow flexion and stride length at foot contact phase, maximum shoulder external rotation at arm cocking phase and knee flexion at ball release phase. The findings suggest that correct pitching movement may assist in increasing ball velocity and potentially prevent injury.