A basic study on a method of evaluating 3-dimentional foot movements in walking

Lower limb motor function is important for activities of daily living. Since gait movements of elderly subjects differ from those of young people, gait measurement is considered to be effective for evaluating lower limb motor function. In this paper, focusing on foot movements during gait, a method of evaluating 3-dimentional movements of the foot during walking was examined. Gait movements were measured with 3 healthy females using the wireless inertial sensor system developed by our research group. Then, foot inclination angle and vector locus of the foot vector were calculated from angular velocity and acceleration signals by using quaternion-based attitude representation. They were projected onto each plane of the global coordinate system. The results showed similar angle waveforms and locus patterns between subjects. These suggested that the angles and the vector loci would be useful in evaluation of lower limb motor function. Developing quantitative evaluation method and making clear meanings of the angles and the vector loci projected to the planes are necessary.