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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 JR, Channon AJ, Myatt JP, Rankin JW, Hubel TY. J R Soc Interface. 2012 May 9.
Quote:
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.
I should be interested to hear if this new model achieves similar energetic fluctuations along with ground reaction forces observed in-vivo. "The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?" Nope, it's a bipedal-spring mass model of walking in which the leg stiffness is modulated within the step.
You still prefer an inverted pendulum model of walking, Kevin?
Re: The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?
Quote:
Originally Posted by Simon Spooner
You still prefer an inverted pendulum model of walking, Kevin?
Yes, Simon, I do prefer an inverted pendulum model of walking to model the energetics of walking versus running, and still use it in all my lectures on walking vs. running biomechanics.
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Re: The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?
Quote:
Originally Posted by Kevin Kirby
Yes, Simon, I do prefer an inverted pendulum model of walking to model the energetics of walking versus running, and still use it in all my lectures on walking vs. running biomechanics.
Do you include compliant leg behaviour in your walking model?
Re: The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?
Quote:
Originally Posted by Simon Spooner
Do you include compliant leg behaviour in your walking model?
Not specifically in reference to the energetics of walking.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Re: The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?
Quote:
Originally Posted by Simon Spooner
OK, so your only using the inverted pendulum model to explain energetics and not reaction forces etc.
Correct.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
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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