ハンマー投ターン局面におけるハンマーヘッド加速技術の研究
―ハンマーヘッド加減速パターンの違いに着目して―

抄録

The purpose of this study was to investigate techniques for accelerating the hammer head in the turn phase of the hammer throw by comparing the motions of hammer throwers. Ten male throwers (PB: 43.15-68.21 m) participated in the study. The hammer motions were videotaped on high-speed VTR cameras (250 or 200 fps), and three-dimensional coordinates were calculated using a DLT method. Various kinematic parameters were calculated, including the hammer head speed, the increase in hammer head speed at each turn phase, the leading distance of the handle (hand), the horizontal abduction/adduction angle of the left arm (shoulder), the twist angle of the trunk, the rotation angle of the pelvis, and the horizontal abduction/adduction angle of the left hip. The fundamental factors and techniques responsible for accelerating the hammer head were as follows: (1) Increasing the acceleration and decreasing the deceleration of the hammer head in the turn phase increased the release speed of the hammer head. (2) A longer positive leading distance of the handle (hand), defined as the distance from the handle to the line connecting the hammer head and the instantaneous center of rotation of the hammer head, had a larger effect on the acceleration of the hammer head in the turn phase. (3) The horizontal abduction of the leading arm (shoulder), the negative trunk twist (recoiling motion), and the sway motion at the midpoint between the two shoulder joints toward the rear and trailing-arm side of the body increased the positive leading distance of the handle by generating the power of the legs and trunk simultaneously.