These Feet Were Made for Walking (and Running)

first_imgWe usually walk or run.  When walking, we roll from heel to arch to toe and rock our arms back and forth.  When running, we bounce up and down slightly while pumping our arms.  Did you know that many other gaits are possible?  Why do we use only two?  A team of specialists in bio-robotics at Cornell decided to apply a mathematical model to human foot travel.  Like true scientists, they asked questions about the obvious:Why do people not walk or even run with a smooth level gait, like a waiter holding two cups brim-full of boiling coffee?  Why do people select walking and running from the other possibilities?  We address such questions by modelling a person as a machine describable with the equations of newtonian mechanics.  The basic approximations are: first, that humans have compact bodies and light legs; second, that gait choice is based on energy optimization; and third, that energy cost is proportional to muscle work.  We use a simplification of previous models, perhaps the simplest mechanical model that is capable of exhibiting a broad range of gaits that includes walking and running.  Although the model is a mechanical abstraction that is not physically realizable, it is subject to the laws of physics.  Because of its simplicity, the model is amenable to interpretation.  It can also be studied with exhaustive and accurate simulation experiments, far beyond what is possible with human subjects.   (Emphasis added in all quotes.)So, putting the model in the computer and cranking out the equations, they discovered that these two gaits are the most energy efficient for beings our size and shape.  Their only mention of evolution referred to the fact that, in their model, running did not require elastic spring energy: “human ancestors could have started to run before the modern human long Achilles tendon was fully evolved.”  Their derivations were published in Nature.11Srinivasan and Ruina, “Computer optimization of a minimal biped model discovers walking and running,” Nature 439, 72-75 (5 January 2006) | doi:10.1038/nature04113.That statement merely assumes evolution, again – the mortal sin of Darwinists.  “Before the Achilles tendon was fully evolved,” right.  Since evolution is already a fact to these dogmatists, it must make perfect sense.  After all, running in circles in a big enough squirrel cage provides the illusion of making progress down a straight track.    Human bodies can be treated like physical objects and described according to physical laws.  Drop yours out a window and you will accelerate at thirty-two feet per second squared till reaching terminal velocity.  The crater you formed can be measured, and the force you generated on impact can be calculated.  The mechanics of running can be described, quantified, and modeled (see 11/18/2004).  This is all wonderful and useful, but says nothing about how humans, and these mechanical abilities, arose.  Nor does it say how we should use them.  Newton needed to look elsewhere for those laws: Walk circumspectly; do not run in vain.(Visited 13 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img

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