Transverse contributions to the longitudinal stiffness of the human foot

Fuente: arXiv
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Main Authors: Yawar, Ali, Korpas, Lucia, Mandre, Shreyas, Venkadesan, Madhusudhan
Format: Preprint
Published: 2017
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_version_ 1866912669160701952
author Yawar, Ali
Korpas, Lucia
Mandre, Shreyas
Venkadesan, Madhusudhan
author_facet Yawar, Ali
Korpas, Lucia
Mandre, Shreyas
Venkadesan, Madhusudhan
contents Humans rely on foot stiffness to withstand the propulsive forces of walking and running. Skeletal adaptations that increase foot stiffness include the medial longitudinal arch (MLA) and the transverse tarsal arch (TTA). The TTA has been hypothesized to stiffen the foot through cross-axis coupling of transverse intermetatarsal stiffness with sagittal-plane midfoot stiffness, but this has been tested only in cadaveric specimens. In vivo testing is essential because muscle contraction substantially modulates MLA function and may similarly affect the TTA's cross-axis coupling. Here we provide in vivo evidence for the TTA's contribution to foot stiffness by externally increasing intermetatarsal stiffness and measuring its effects on midfoot elasticity during walking. As predicted by the cross-axis coupling hypothesis, increasing intermetatarsal stiffness with an elastic tape wrapped around the forefoot reduced the energy absorbed in midfoot flattening and increased sagittal-plane midfoot stiffness concomitantly (mean,$\pm$,standard error of the mean (SEM): $13.9\% \pm 3\%$ and $16.8\% \pm 5.8\%$, respectively). However, taping did not change the curvature of the TTA, thereby isolating the effects of cross-axis coupling from morphological changes to the TTA. Thus, forefoot taping modulates midfoot stiffness through cross-axis coupling and could provide a non-invasive means to manage pathological foot flexibility or enhance athletic performance.
format Preprint
id arxiv_https___arxiv_org_abs_1706_04610
institution arXiv
publishDate 2017
record_format arxiv
spellingShingle Transverse contributions to the longitudinal stiffness of the human foot
Yawar, Ali
Korpas, Lucia
Mandre, Shreyas
Venkadesan, Madhusudhan
Biological Physics
Other Quantitative Biology
Humans rely on foot stiffness to withstand the propulsive forces of walking and running. Skeletal adaptations that increase foot stiffness include the medial longitudinal arch (MLA) and the transverse tarsal arch (TTA). The TTA has been hypothesized to stiffen the foot through cross-axis coupling of transverse intermetatarsal stiffness with sagittal-plane midfoot stiffness, but this has been tested only in cadaveric specimens. In vivo testing is essential because muscle contraction substantially modulates MLA function and may similarly affect the TTA's cross-axis coupling. Here we provide in vivo evidence for the TTA's contribution to foot stiffness by externally increasing intermetatarsal stiffness and measuring its effects on midfoot elasticity during walking. As predicted by the cross-axis coupling hypothesis, increasing intermetatarsal stiffness with an elastic tape wrapped around the forefoot reduced the energy absorbed in midfoot flattening and increased sagittal-plane midfoot stiffness concomitantly (mean,$\pm$,standard error of the mean (SEM): $13.9\% \pm 3\%$ and $16.8\% \pm 5.8\%$, respectively). However, taping did not change the curvature of the TTA, thereby isolating the effects of cross-axis coupling from morphological changes to the TTA. Thus, forefoot taping modulates midfoot stiffness through cross-axis coupling and could provide a non-invasive means to manage pathological foot flexibility or enhance athletic performance.
title Transverse contributions to the longitudinal stiffness of the human foot
topic Biological Physics
Other Quantitative Biology
url https://arxiv.org/abs/1706.04610