title: Footfall dynamics for racewalkers and runners barefoot on compliant surfaces.
abstract: The main purpose of this study is to investigate the role of footfall surface compliance on the physical parameters affecting barefoot racewalkers and runners. These parameters are identified using a new inverted pendulum body model with a forward moving foot pivot. Model correlations of footfall loads measured for four compliant surface mats showed leg-foot compression stiffness for both gaits were in the range of 10.8-12.9 kN/m, with the initial stiffness spikes in the range of 6.5-52 kN/m. The average leg damping factor was about 0.6% for racewalkers and 6% for runners. For both gaits there was negative leg damping just prior to foot lift-off. Compared to the peak reactions for the rigid surface, a mat of intermediate compliance (1020 kN/m) was effective in reducing the runners' peak reaction spikes by as much as 17%.
authors.affiliation: Department of Civil and Environmental Engineering, Pratt School of Engineering, Duke University, 6319 Mimosa Drive, Chapel Hill, NC 27514, USA. jwilson@duke.edu
authors.forename: James F
authors.initials: JF
authors.lastname: Wilson
authors.forename: Rodger D
authors.initials: RD
authors.lastname: Rochelle
mesh_terms: D000328:Adult; D003198:Computer Simulation; D004548:Elasticity; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012775:Shoes; D016138:Walking / Q000502:physiology*