Abstract
In most judo accident, recently, it is reported that the victims suffers severe head injury and in particular, the acute subdural hematoma (ASDH) caused by the rupture of the veins due to angular accelerations. The angular accelerations also have some influences on the development of the concussion and the Diffuse Axonal Injury (DAI). It is thought that the concussion and ASDH occur from the angular accelerations in the sagittal direction and DAI in the coronal direction respectively. It is reported that the tactic Osoto-gari often involves in the judo accidents. On the angular acceleration, of three directions (sagittal, coronal and horizontal direction), the remarkable change was observed in coronal one in Osoto-gari. So the purpose of the experiment is to examine the generating mechanism of the traumatic brain injury while paying attention to a head angular acceleration which Uke takes comparing the Yoko-ukemi. The both peak of angular velocity and angular acceleration were observed just after the palms made contact with the floor. Since each value was much smaller than the threshold value of a concussion, it can be said that a possibility that DAI is caused is extremely low. Since the waveform change was alike in Osoto-gari and Yoko-ukemi, moreover, it is thought that it is necessary for judo players to master Yoko-ukemi together with Ushiro-ukemi paying due attention not to have a temporal blow besides a occipital one in the practice of Osoto-gari.
