Biomechanical Analysis of the Head Movements of a Person Thrown by the Judo Technique ‘Seoi-nage’

Abstract

The present study examined the kinematics and biomechanical parameters of the head of a person thrown forward by the judo technique 'Seoi-nage'. A judo expert threw an anthropomorphic test device (the POLAR dummy) five times. Kinematics data were obtained with a high-speed digital video camera. Linear and angular accelerations of the head were measured by accelerometers mounted at the center of gravity of the dummy's head. When Seoi-nage was performed, the dummy fell forward accompanied by contacting the anterior parietal regions of the head to the tatami, and the linear and angular accelerations of most axes reached peak values when the head contacted the tatami. Peak resultant linear and angular accelerations were 20.3 ± 9.8 G and 1890.1 ± 1151.9 rad/s 2 , respectively (means ± standard deviation). Peak values in linear and angular acceleration did not significantly differ between the three directional axes. Absolute angular accelerations in all axes observed in Seoi-nage were high and the resultant value was approximately equal to the already reported in Ouchi-gari, one of the predominant techniques causing judo-related acute subdural hematoma. However, the remarkable increase of linear acceleration in the longitudinal direction and/or angular acceleration in the sagittal plane, as previously reported in techniques being thrown backward (i.e., Ouchi-gari and Osoto-gari), was not detected. The likely mechanism of acute subdural hematoma caused by Seoi-nage is that a large angular acceleration causes large strains and deformations of the brain surface and subsequent rupture of cortical vessels.

Risk assessment in different Judo techniques for children and adolescent athletes

“…Higher a p and _ v p , and greater u f found in backward techniques, especially in o-soto-gari, aligned the current results with previous findings, supporting intrinsic risks related to the rear falls compared to forward throws. 9 In this study, lower a p and _ v p results were found compared to Murayama et al 13,40 and Hitosugi et al 14 However, in previous studies, 13,14,40 an anthropometric test device was used, and since it was a passive dummy, there was always an impact of the head with the tatami. In contrast, in this study, participants react to prevent the head to impact on the tatami (despite sometimes it occurred).…”

Comparison of head impact measurements via an instrumented mouthguard and an anthropometric testing device

“…More recent research has developed technology to enable quantification of HIE in non-helmeted contact sports such as rugby union, boxing and martial arts [38]. For example, a skin mounted sensor (xPatch; X2 Biosystems, Seattle, Washington USA), which is worn on the mastoid process, comprises a triaxial accelerometer and gyroscope.…”

Ukemi Technique Prevents the Elevation of Head Acceleration of a Person Thrown by the Judo Technique ‘Osoto-gari’

“…Osoto-gari has been reported to be the most common throwing technique causing severe head injuries, followed by ouchi-gari and seoi-nage, in judo. 3,4) In previous studies, 9,10,14,15) we biomechanically examined the head acceleration of an anthropomorphic test device (ATD), namely the POLAR dummy, 16) which is a pedestrian dummy used in vehicle crash testing) when the head strikes the tatami after being thrown by the three techniques listed above. The results are for falls without ukemi and they are compared with those for a judo expert falling with good ukemi ability in the present paper.…”