Variability and Coordinative Function in Human Gait

Abstract

Recent research from a dynamical and complex systems perspective has shown that loss of complexity and variability may characterize changes in biological function due to aging and disease. We provide an overview of the empirical evidence for the functional role of variability in the stability and adaptability of human gait. This evidence is derived from research on coordination within the motor system as well as between different physiological systems, such as in the coupling between locomotor and respiratory rhythms. Coordinative analyses of relative phase between segments of the lower extremities and between pelvis, trunk, and head are shown to be instrumental in pinpointing age and disease related changes in gait. These analyses also provide powerful tools in uncovering the different compensatory strategies available to older individuals and those suffering from neurological and orthopedic disorders.