title: The Foot's Arch and the Energetics of Human Locomotion.
abstract: The energy-sparing spring theory of the foot's arch has become central to interpretations of the foot's mechanical function and evolution. Using a novel insole technique that restricted compression of the foot's longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms(-1)) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running.
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, 6009, Australia.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Stearne
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, 6009, Australia.
authors.forename: Kirsty A
authors.initials: KA
authors.lastname: McDonald
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, 6009, Australia.
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Alderson
authors.affiliation: Willetton Podiatry, Willetton, WA, 6155, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: North
authors.affiliation: School of Anatomy, Physiology and Human Biology, The University of Western Australia, Perth, WA, 6009, Australia.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Oxnard
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, 6009, Australia.|Biomechanics Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA.
authors.forename: Jonas
authors.initials: J
authors.lastname: Rubenson
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008124:Locomotion; D008684:Metatarsus / Q000033:anatomy & histology* / Q000502:physiology*; D008954:Models, Biological; D009043:Motor Activity; D012420:Running; D016138:Walking