A Study of a Fall Prevention System for Patients with Walking Disabilities

Abstract

Falls in people with walking disabilities lead to being bedridden and an increase in long term care. The prevention of these incidents is thus a key factor in maintaining activity level and maximizing their Quality of Life (QOL). The sagittal plane motion has been widely studied, but there are few studies about frontal plane motion such as falls to the side. In this study, we focus on frontal plane motion and consider fall prevention by plantar height. Because falls may occur when the center of gravity, which is followed by the ground reaction force, is shifted from the base of support, giving plantar height can be applied to fall prevention. The purpose of this paper is to assess the effect of plantar height on fall prevention. We used two types of theoretical models, an inverted pendulum model and a self-righting doll model. First, the motion in the frontal plane of a developed leg foot model was observed. Then, its motion was compared with the simulation results. As a result, the simulation of the self-righting doll was close to the experimental model. Second, the relation between plantar height and radius of the foot was considered. As a result, the radius of the foot would be estimated at 0.77 m and 0.13 m under “without height conditions” and “with height conditions”, respectively. From the viewpoint of the equation of motion of the self-righting doll, restoring torque resisting fall increased with decreasing the radius of the foot. From the above, this paper indicates that the self-righting doll model is valid as the leg foot model, and the plantar height affects fall prevention.