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The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

ABSTRACT: Mechanically, the most economical gait for slow bipedal locomotion requires walking as an 'inverted pendulum', with: I, an impulsive, energy-dissipating leg compression at the beginning of stance; II, a stiff-limbed vault; and III, an impulsive, powering push-off at the end of stance. The characteristic 'M'-shaped vertical ground reaction forces of walking in humans reflect this impulse-vault-impulse strategy. Humans achieve this gait by dissipating energy during the heel-to-sole transition in early stance, approximately stiff-limbed, flat-footed vaulting over midstance and ankle plantarflexion (powering the toes down) in late stance. Here, we show that the 'M'-shaped walking ground reaction force profile does not require the plantigrade human foot or heel-sole-toe stance; it is maintained in tip-toe and high-heel walking as well as in ostriches. However, the unusual, stiff, human foot structure--with ground-contacting heel behind ankle and toes in front--enables both mechanically economical inverted pendular walking and physiologically economical muscle loading, by producing extreme changes in mechanical advantage between muscles and ground reaction forces. With a human foot, and heel-sole-toe strategy during stance, the shin muscles that dissipate energy, or calf muscles that power the push-off, need not be loaded at all--largely avoiding the 'cost of muscle force'--during the passive vaulting phase.

SUBMITTER: Usherwood JR

PROVIDER: S-EPMC3427509 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

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The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

Usherwood J R JR Channon A J AJ Myatt J P JP Rankin J W JW Hubel T Y TY

Journal of the Royal Society, Interface 20120509 75

Mechanically, the most economical gait for slow bipedal locomotion requires walking as an 'inverted pendulum', with: I, an impulsive, energy-dissipating leg compression at the beginning of stance; II, a stiff-limbed vault; and III, an impulsive, powering push-off at the end of stance. The characteristic 'M'-shaped vertical ground reaction forces of walking in humans reflect this impulse-vault-impulse strategy. Humans achieve this gait by dissipating energy during the heel-to-sole transition in e ...[more]

PMID: 22572024

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The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

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The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

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