We studied the influence of hand breaking on sharing effective mass and impact force at sideways falls, since hip fractures in elderly are mainly caused by sideways falls. When the hand contacted the ground before the great trochanter, the effective mass and impact force of the great trochanter were shared on the hand in the both case of one-hand and both-hands contacts. However, when the great trochanter contacted before the hand, the effective mass and impact force were not shared. Consequently, we suggest that hand contact before the great trochanter at sideways fall is shared the effective mass cause of impact force, and contributes to prevent the hip fracture.
