Dynamic analysis of walking stability

Patients with walking disorders are diagnosed by orthopedics and a rehabilitation course in a hospital, but the walking of physically unimpaired persons is not diagnosed. It is considered that if they continue to walk unstably, this may cause lower-back pain or knee pain; this burden also exerts bad influences upon other physical parts. So it is important that we analyze walking stability of physically unimpaired persons as one aspect of preventive medicine. The center of gravity (COG) plays an important role in evaluation of stability for both standing posture and walking. In the present study, we used an acceleration measurement system. Using this system, we measured the acceleration displacement at the COG of a normal walking subject and evaluated walking stability quantitatively. We noted the periodicity and rhythm of the acceleration displacement of normal subjects while they walked, using a seasonal adjustment model to predict periodic fluctuations. We assessed walking stability, quantitatively, using the ratio of the variance of the noise component vs. the variance of periodic component. This study provides useful information for understanding walking systems in preventive medicine and rehabilitative medicine.