The purpose of this study was to investigate, using path analysis, causal relationships among motion factors for achieving a high release velocity in the male discus throw. The throwing motions of 61 male discus throwers were analyzed using three-dimensional motion analysis. Variables such as release velocity, velocities gained by each body segment, body segment velocity, body angle and angular velocity were obtained. The path model indicating the causal relationships among these factors was constructed by path analysis.
The main results were as follows:
Influences of velocities gained by each body segment on release velocity were largest for the arm, followed in order by the trunk and legs.
Motion factors such as weight shift, acquisition of the velocity of the center of gravity, sweeping the legs, rotations of the hip and shoulder, twisting and untwisting of the trunk, acquisition of the velocity of the right knee and extension of the left knee had direct or indirect influences on the velocities gained by each body segment.
Motion factors in the path model revealed causal relationships along the time sequence of the throwing motion. In addition, the path model in this study indicated the cause and effect structure of the throwing motion by which Japanese male discus throwers were able to achieve a high release velocity. The results of this study can be utilized for technical coaching of the discus throw based on causal relationships.