Kinematic Comparison of Throw-Down Mechanics Between Baseball and Softball Catchers

Based on previous research, catchers' throwing mechanics between baseball and softball tend to be viewed as comparable despite the inherent differences in playing conditions. When compared at key throwing timepoints, differences in pelvis and trunk kinematics were observed between sports. However, it is uncertain whether throwing-arm mechanics would differ throughout the throw between these athletic populations. Therefore, this study aimed to compare catchers' throwing mechanics between sports using continuous statistical analyses. A total of 20 catchers (baseball: n=10 and softball: n=10) participated in this study. Statistical parametric independent samples t-tests (α=0.05) were used to temporally compare proximal and throwing-arm kinematics from foot contact (0%) to maximum shoulder internal rotation (100%) between sports. Differences found included elbow flexion (p=0.008; 0-13 and 99-100%), shoulder rotation (p<0.001; 23-53%), elevation (p<0.001; 0-95%) and the plane of elevation (p<0.001; 0-100%), pelvis and trunk lateral flexion (pelvis: p=0.027; 0-30% and trunk: p<0.001; 23-100%) and rotation (pelvis: p=0.036; 4-21% and trunk: p=0.036; 84-100%), and trunk flexion (p<0.001; 34-100%). While most of the observed differences were brief, notable differences in the trunk flexion, trunk lateral flexion, shoulder elevation, and plane of elevation were apparent for much of the throwing motion. Time-series analyses identified distinct mechanics involved in baseball and softball throw downs, lending support for sport-specific biomechanical assessments on catchers.