Gait Stability Analysis with a Two-dimensional Dynamic Parameter

Abstract

Objective: To define a two-dimensional (2-D) region of stability derived by center of mass (COM) velocity, and to assess the dynamic walking stability with COM position and velocity. Methods: The 2-D base of support (BOS) was determined by the intersection between the vector of the 2-D COM velocity and the envelope of the foot pressure. The region of stability for velocity (ROSv) in 2-D were determined using normalized COM position and velocity at toe off (TO). In order to exam the utility of this new parameter, fourteen elderly females with and without history of falls participated into a walking experiment. Results: The results showed that the 2-D ROSv could distinguish the coordinates difference between two groups much better than 1-D form in antero-posterior. COM position of elderly fallers demonstrated significant closer to the foot supporting boundary than that of healthy elderly adults at TO. Conclusion: The parameter of 2-D ROSv could differentiate among dynamic stability for healthy elderly adults and fallers. The results of walking experiment revealed elderly fallers tend to walk more conservatively compared to healthy subjects, to relieve the pressure of controlling their momentum.