Rotational acceleration during head impact resulting from different judo throwing techniques

Area of Science:

• Biomechanics
• Sports Medicine
• Traumatology

Background:

• Acute subdural hematoma is a severe head injury frequently reported in judo.
• Understanding the mechanisms of judo-related head injuries necessitates examining head rotational acceleration.
• Judo throws can impart significant forces to the head.

Purpose of the Study:

• To determine the rotational acceleration of the head during judo throws.
• To analyze the mechanisms of head injuries in judo by measuring head accelerations.
• To investigate the effect of an under-mat on head accelerations during throws.

Main Methods:

• An anthropomorphic test device was subjected to Osoto-gari and Ouchi-gari judo techniques by an expert.
• Rotational and translational head accelerations were measured with and without an under-mat.
• Kinematic data were analyzed to determine peak acceleration values.

Main Results:

• Peak resultant rotational acceleration ranged from 1,708.0 to 5,525.9 rad/s(2) and translational acceleration from 64.3 to 149.4 g.
• The under-mat did not significantly reduce resultant rotational acceleration for either technique.
• Head contact with the tatami correlated with peak translational and rotational accelerations.

Conclusions:

• Both translational and rotational head accelerations are crucial for analyzing judo head injury mechanisms.
• Head impacts with the tatami are a key factor in achieving peak acceleration values.
• Restricting throwing techniques to skilled participants with proficient ukemi skills may prevent head injuries.