It is a common knowledge that the motion of the head plays an important role in applying the Judo throwing techniques. It greatly influences the retention of the posture in the process of the applying the techniques, and also affects the making full use of the power which is needed in the throwing.
In this study, we regard the motion of the head, the shoulders, and the hip, which affect very much the throwing, as the rotary motion against the median line; and we try to explain in what way the head, the shoulders, and the hip move and how thiw rotary motion affects the motion of the head in the throwing.
The following results was obtained.
1) It was observed that in the case of well-trained the body had turned round before the head began to turn at the completion of “Taisabaki” (body turning) and the motion of the head was restrained; but in the case of middle-trained and untrained, the head had turned round before the shoulders at the completion of “Taisabaki” (body turning).
2) In the phase of “Kake” (attack) of well-trained, the head turned round at a time, and a angle difference could be observed between the head, the shoulders and the hip; i. e. the head had turned first, the followed the shoulders, and the hip: and this angle difference between the head and the body was smaller than the case of middletrained and untrained. Therefore we could say that the head, the shoulders, and the hip co-ordinated well in this case. But in the case of middle-trained and untrained the angle difference which was observed at the completion of “Taisabaki” (body turning)continued, and it became even larger than it was at the completion of “Taisabaki”(body turning). So in the case of middle-trained and untrained, it was observed that only the head turned round too much in the throwing.
3) In the case of middle-trained and untrained, it was observed at the phase of “Kake”(attack) that the position of the hip was too high, so therefore the direction of “Hikite”(pulling hand) was not correct, and “Tsurite” (lifting hand) did not work well, so that the motion of the shoulders was restricted. The motion of the shoulders is important to the effective motion of the head. This motion of the shoulders is influenced by the correct position of the hip and the correct direction of “Hikite” (pulling hand)and the correct way of “Tsurite” (lifting hand).
