The objective of this study was to demonstrate three-dimensional neck kinematics during breakfall motion for osoto-gari and to elucidate its association between neck strength in novice judokas.We found the neck motion occurs multidirectionally during the breakfall motion. In addition, the present result showed that the peak neck angular momentum the in frontal and horizontal plane accounted for approximately 30% of the peak neck extension momentum. Finally, there was no linear relationship between the peak resultant neck angular momentum and neck flexion strength, suggesting that neck strength in the single motion plane alone may not be associated with the risk of head injuries during judo.
