The present study investigated the differences in the stride pattern of the lower extremities among different stride types in baseball pitchers with the aim of evaluating stride movement and skills to improve training effectiveness. Thirty elite male college baseball pitchers volunteered to pitch on an indoor-mound-like force plate, where motion data of their fastest strike trials were collected using an eight-camera motion analysis system at a 200–250 Hz sampling rate. Pelvis center trajectories of each participant were calculated and further categorized into three groups: tall-and-fall (TF), dip-and-drive (DD), and mixed (MX) pitchers. Motion analysis revealed that DD pitchers initiated pivot–knee extension and pivot–hip adduction earlier than TF pitchers and accelerated their bodies sooner than TF pitchers. In addition, TF pitchers accelerated their bodies forward by pivoting their legs until the middle of the arm-cocking and acceleration phases. The movement patterns of MX pitchers were similar to those of DD pitchers in terms of pivot leg, although this occurred a little later in the stride. Our findings are useful in developing training strategies for coaches, players, and trainers to better meet the demands of different pitching styles.

These findings suggest that the ratio of biceps concentric to triceps concentric functional strength strongly predicts elbow-injury status in baseball players. Assessment of this ratio may prove useful in a practical setting for training purposes and both injury diagnosis and rehabilitation.

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This paper examined the plausibility of using 2D images to estimate the center of mass of the human body (CoMb) and the performance using the trajectory of CoMb as an event detector for baseball swing movement. Movement data from three subjects are collected using both a motion capture system and a commercial camera, and the resultant 2D skeleton and CoMb position from the 2D images are obtained using two pose estimation algorithms and an anthropometry model. The errors of the 2D results are 42.67 mm for the skeleton and 50.69 mm for CoMb estimation. 88 baseball swing movement videos are used to illustrate the performance of CoMb trajectory as an event detector with a baseball expert. The agreement was 90.91% between the CoMb trajectory and the baseball expert.