This study delineates the common characteristics of pitching motion in professional baseball pitchers by focusing on their lower limbs. Further, to gain an insight into the development of athletic capacity, the pitching motion of the Top group was compared with the Minor group, resulting in the clarification of lower limb issues in the Minor group. Data analysis was performed using a test with the highest score in a 5-point objective evaluation by the observer and the highest ball speed in the tracking data obtained from Trackman, with the following results: (1) The common characteristics in a professional baseball pitcher was that the hip joint was flexed while the stride leg knee joint angle was fixed to MBV (Minimum Ball Velocity), MER (Maximal Shoulder External Rotation), and the stride leg hip joint and knee joint were slightly extended to MER, REL (Ball Release). (2) Regarding the difference between the Top and Minor groups, it is suggested that the Top group accelerates the rotational speed of the lower torso to SFC (Stride Foot Contacts Ground), which increases the angular velocity of adduction of the hip joint of the stride leg, resulting in torsion of the trunk and stable force transmission after MBV. (3) In the Top group after SFC, the angular displacement and angular velocity was such that the hip joints of both legs were fixed. Additionally, the stride leg hip joint was in adduction, which caused the motion to increase the rotation of the lower and upper torsos. Authors suggest considering these key points while coaching baseball.
