Was man's clearance always so small?
I believe not. I believe that early man probably walked with much more
back flexion. (although I have forgotten any anthropology I once knew)
Also if you look at those pictures you sent this early man walked with
an abducted gait. He might have had an inability to utilize his first
MPJ (hallux limitus) and had to walk so he could clear the mpj that he
couldn't in the sagittal plane. This also might have caused some
increased flexion at the hip and knee as well.
Why does clearance become even smaller in the elderly?
As we get older we start to loose the ability to have a single limb
stance with heel off. If you watch the way an elderly person walks
especially one who is fixed in back flexion, you will see that the heel
of the stance foot does not come off of the ground before the other heel
strikes. This is for stability.
Gilbert L. Gulbrandson, C.O.
Animals, including humans, have a remarkable ability to find the most
efficient way to move from point A to point B. It seems to be a tendency
for all animal species to conserve energy during most activities. Reducing toe
clearance during swing phase is likely much more energy efficient than
increasing toe clearance and therefore, a much more economical strategy of
moving from point A to point B.
I suspect that the proprioceptive mechanisms present within our
extremities allow us to "sense the ground with our toes" to improve
efficiency without causing injury (stubbing a toe and tripping). It is
quite amazing. It almost seems, at times, like the toes have eyes to only clear
the ground by the bare minimum during midswing.
Kevin A. Kirby, D.P.M.
Assistant Clinical Professor of Biomechanics
California College of Podiatric Medicine
2626 N Street
Sacramento, CA 95816
Voice: (916) 456-4768 Fax: (916) 451-6014
Unfortunately there was no one around to capture the early walking style
and although the footprints look familiar it may be cautionary not to
assume too much familiarity.
Throughout history the gait patterns of the privilaged classes
altered to fit social mores. The introduction of the fashion heel (for
males) for example in the seventeenth and eighteenth centuries made
mincing gait the norm for the best part of a century . Similarly in the
fifteenth and sixteenth century Venice , the wearing of chopines or high
platforms caused changes to body deportment necessitating the
introduction of walking stick as a fashion accessory. In pre-revolution
France, books on ettiquette clearly outline the importance of the short
step style (for females) brought on by wearing tight fitting high heel
shoes . The classic sado-ritualistic example is of course foot binding in
China, this practice lasted a millenium.
My point being although the physical parameters may be governed by
anthrompometry, there is still a wide variation in individual gait
Department of Podiatry Tel:
Curtin University of Technology Fax: +61-08-9-266-3679
Shenton Park, WA 6008
Since Cleopatra first stuck nugget sized diamonds between her toes and
Hari bound her ankles with sapphire-encrusted sandals, every hedonistic
phase of fashion, whether the Naughty Nineties or the Roaring Twenties,
indulged in sumptuous, visually edible footwear.
I think that, in general,
people "learn" the environment pretty
quickly. For instance, try running across extremely broken, and uneven, terrain. Many
people who enjoy orienteering and hashing do this all the time, yet very few
of them fall over or even change their stride much. Presumably they have a
greater toe clearance in the rougher terrain, yet they adapt quickly and
don't appear to walk any differently when they return to civilization.
It might make an interesting
study - take a number of subjects and
measure their toe-clearance in your gait lab. Then send them off for either a two
mile run on the pavement or a two mile run over broken terrain. Re-measure
their toe clearance as they return.
Alternatively you could make
your gait lab conform to the real world
and do a few tests with the odd door-mat, carpet and children's toys littering the
calibration area and see what happens to the toe clearance...
Motion Lab Systems, Inc.
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