Rotational Acceleration during Head Impact Resulting from Different Judo Throwing Techniques
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- MURAYAMA Haruo
- Department of Sports Science, Dokkyo Medical University School of Medicine Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi
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- HITOSUGI Masahito
- Department of Legal Medicine, Dokkyo Medical University School of Medicine
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- MOTOZAWA Yasuki
- Department of Legal Medicine, Dokkyo Medical University School of Medicine
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- OGINO Masahiro
- Department of Neurosurgery, Dokkyo Medical University School of Medicine
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- KOYAMA Katsuhiro
- Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi
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Abstract
Most severe head injuries in judo are reported as acute subdural hematoma. It is thus necessary to examine the rotational acceleration of the head to clarify the mechanism of head injuries. We determined the rotational acceleration of the head when the subject is thrown by judo techniques. One Japanese male judo expert threw an anthropomorphic test device using two throwing techniques, Osoto-gari and Ouchi-gari. Rotational and translational head accelerations were measured with and without an under-mat. For Osoto-gari, peak resultant rotational acceleration ranged from 4,284.2 rad/s2 to 5,525.9 rad/s2 and peak resultant translational acceleration ranged from 64.3 g to 87.2 g; for Ouchi-gari, the accelerations respectively ranged from 1,708.0 rad/s2 to 2,104.1 rad/s2 and from 120.2 g to 149.4 g. The resultant rotational acceleration did not decrease with installation of an under-mat for both Ouchi-gari and Osoto-gari. We found that head contact with the tatami could result in the peak values of translational and rotational accelerations, respectively. In general, because kinematics of the body strongly affects translational and rotational accelerations of the head, both accelerations should be measured to analyze the underlying mechanism of head injury. As a primary preventative measure, throwing techniques should be restricted to participants demonstrating ability in ukemi techniques to avoid head contact with the tatami.
Journal
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- Neurologia medico-chirurgica
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Neurologia medico-chirurgica 54 (5), 374-378, 2014
The Japan Neurosurgical Society