ON THE MEASUREMENT OF DYNAMIC STABILITY OF HUMAN LOCOMOTION

The main focus of the present investigation is the development of quan titative measures to assess the dynamic stability of human locomotion. The analytical methodology is based on Floquet theory, which was deve loped to investigate the stability of nonlinear oscillators. Here the basic approach is modified such that it accommodates the study of the complex dynamics of human locomotion and differences among various ind ividuals. A quantitative stability index has been developed to charact erize the ability of humans to maintain steady gait patterns. Floquet multipliers of twenty normal subjects were computed from the kinematic data at Poincare sections taken at four instants of the gait cycle, n amely heel strike, foot flat, heel off, and toe off. Then, an averaged stability index was computed for each subject. Statistical analysis w as performed to demonstrate the utility of the stability indices as qu antitative measures of dynamic stability of gait for the subject popul ation tested during the present study.