Ecological gait dynamics: stability, variability and optimal design

Variability–stability relationships are the very foundation of flexible biological movements. For footwear design, stability is best defined as pattern stability at the level of segmental relationships with regard to goal-oriented performance. Footwear design should seek to optimize the variation in segmental relationships while maintaining the overall locomotion pattern, providing a system that is both adaptable to upcoming events and stable to unanticipated perturbations. As footwear is designed for a variety of uses other than forward, continuous running on a flat terrain, an examination of the fundamental assumptions and applicability of traditional gait dynamics is necessary. Expanding evaluation of gait dynamics to non-forward, non-continuous motion across different terrains would seem appropriate, given the ubiquity of these movements in everyday life. Optimizing footwear design for different tasks requires trade-offs between design and material selection and a principled scientific approach to und...