Comparison of Local Dynamic Stability of Treadmill Gait Data in Three Different Planes Through Maximal Lyapunov Exponent

Assessing the dynamic stability of gait is of high need to determine the types of pathology and early detection of possibility of falling. Most of the studies till date concentrated on the sagittal plane gait time series data to analyze stability. Thus, the three-dimensional behavior of human gait has often been overlooked. It is known that the sagittal plane accounts most useful information in gait analysis, but there are some pathologies for which other planes also play an important role. This study investigated normal gait time series kinematic data in three different planes. Local dynamic stability has been analyzed and compared in three different dimensions by Maximum Lyapunov Exponent estimation. An attempt has also been made to analyze the nature of gait signals in those dimensions. Experimental results demonstrate that dynamic stability depends on the directional plane. Hence, it is recommended that instead-of single anatomical plane, analysis of gait should be performed in all of the three directional planes to capture the actual nature of the human gait signal.