The Mechanics and Influence of the Foot-Ground Interaction During Bipedal Walking

Thesis (Ph.D.)--University of Washington, 2021This dissertation explores one of the most ubiquitous aspects of human daily life: the interaction of the foot with the ground while walking bipedally in our environment. Specifically, this dissertation examines the mechanics of the foot-ground interaction during walking outside of the confines of the laboratory and the link between this foot-ground interaction and the energetic cost of locomotion. The first study examined the magnitude of the peak forces occurring at the foot across different velocities and surfaces and found that treadmill walking results in significantly different force magnitudes than free walking. The second study examined the location of the center of pressure on the foot during these peak forces across various terrains and velocities, as well as the consistency of these locations. The results showed that the location of the center of pressure during peak braking is consistently less consistent than during peak propulsion. Finally, the third study explored the relationship between the energetic cost of locomotion and various gait parameters, concluding that the energetic cost of walking is closely related to the magnitude of anteroposterior ground reaction forces as well as the time duration of foot-ground contact during the gait cycle. These results highlight the importance of exploring habitual human locomotion outside of the confines of the laboratory to fully understand the mechanics and energetic cost of walking