Dear Mark

In an earlier posting, re suitability of orthotic materials in extreme cold,
I wrote
 <Presumably there isn't a handy footpath all the way to the north pole.
What
I'm thinking is, on the type of terrain he will be walking on will orthoses
be of any functional use. If you take the view that the aetiology of
biomechanical dysfunction, (of the type that can be corrected / treated by
using foot orthoses), is continually walking on hard flat ground.>
This idea didn't seem to float anyones boat but I wondered if this promted
your latest posting.

For me the the faster decelerations (and therefore higher forces) caused by
walking on hard ground add to the posibility of trauma. The fact that its
flat means that those decelerations ( in biomechanics deceleration is seen
as accelerations of the inertial mass and force = mass times acceleration)
occur regularly and continuously upon the same structures time and time
again. this might be analagous to metal fatigue as seen by continuously
bending a piece of steel in the same way until it fails. Walking on rough
ground would change the attitude of the foot, and therefore the applied
forces at any joint or structure, with each step. Walking on soft ground
such as snow would mean deccelerations would be much slower than on more
usual surfaces and much less likely to cause trauma. Doesn't Kevin Kirby's
Rotational equilibrium theory (is that the correct term?)support this idea.
Also by the same token orthoses could only be effective on fairly flat
ground since any wedging or posting would be negated by the effect of the
changing camber and undulations of the ground being walked on. Even posting
for the variation in rearfoot to forefoot alignment would be overridden by
the ground level differences over the foot length.

                    My thoughts Cheers Dave Smith

----- Original Message -----
From: "Mark Conley" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 14, 2004 2:14 AM
Subject: walking on side of footpaths


> i always advise my pts when walking to use the grass/dirt next to the
> footpaths rather than the footpaths (and roadsurfaces). the logic was that
> we were made to handle the varying, semi-resilient natural surfaces
> rather than the hard and flat synthetic civilized surfaces we are forced
> to use. varying terrain utilises the "whole" rom of our jts, and thus
> reduces the localised wear that level surface w/b'ing causes.   question
> i can't remember the source for this basic pt advice, any ideas,
references
> also while i'm "air", it annoys me when i hear "orthotic" instead of
> orthoses, the former is an adjective (an orthotic device, an orthotic lab
> etc.) and "neuropathic ulcer", isn't the correct term a neurotrophic ulcer
> (caused by neuropathy)
> please straighten me out here if i'm wrong, thanks, mark c
>
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