KINEMATIC COMPARISONS OF THROWING DIFFERENT TYPES OF BASEBALL PITCHES

The purpose of this study was to establish and compare kinematic data among four groups of collegiate pitchers who threw the fastball (FA), change-up (CH), curveball (CU), and slider (SL). Twenty-six kinematic parameters at lead foot contact, during the arm-cocking and arm accele ration phases, and at ball release were measured for 16 collegiate bas eball pitchers. Approximately 60% of these parameters showed significa nt differences among the four pitch variations. The greatest number of differences (14 of 26) occurred between the FA and CH groups, while t he fewest differences (2 of 26) occurred between the FA and SL groups. The CH group had the smallest knee and elbow flexion at lead foot con tact and the greatest knee and elbow flexion at ball release. During t he arm-cocking and arm acceleration phases, peak shoulder, elbow, and trunk angular velocities were generally greatest in the FA and SL grou ps and smallest in the CH group. At ball release the CH: group had the most upright trunk and the greatest horizontal shoulder adduction, wh ile the CU group had the most lateral trunk tilt. Understanding kinema tic differences can help a pitcher select and learn different pitches and can help a batter learn how to identify different pitches.