Dear Kevin, Thankyou  again for your time. In relation to this late mid
stance pronation and your suggested cause from your teacher, with gravity
and mechanics at work do we need a muscular  cause? Isn't body mass itself
going to act downwards and produce a situation where rather than being
pulled into pronation by peroneals we fall into it from lack of opposing
inversion / supination  forces in that at max pronated STJ  we have the
lowest point in cycle? Regards Phill
-----Original Message-----
From: [log in to unmask] <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Monday, 7 September 1998 1:39
Subject: Re: Foot Function in Gait


>Phil:
>
>You wrote:
>
><< Given that we accept the rightness of any
> particular framework or theory is there room for the idea that in the
> forward progression of COM and stance limb over the foot if the pattern of
> motion is influenced by seeking path of least resistance or least energy
> expence then natural variation in joint axis, individual bone segment
> length, soft tissue limitations and ROM  are all going to combine in ways
> that ensure no one particular pattern of compensation occurs.>>
>
>Kevin replies:
>
>I agree with the above statement.
>
>Phil continues:
>
><< So some people
> may exhibit a successful compensation involving late to very late stance
> phase STJ pronation as propriocepters ("Alan and Ken") begin to register
> that 1ST mpj is not going to bend and that plantar loading under prox phal
> of hallux increases as COP moves medially just immediately before heel
off.
> This seems to be followed by the obligatory adductory heel twist.....
> further reducing sag plane blockage by contributing to "getting the foot
out
> of the way" with a corresponding forefoot abduction. Does any of this hold
> water? >>
>
>Kevin replies:
>
>I agree that late midstance pronation occurs and I agree that late
midstance
>pronation does often lead to functional hallux limitus (FHL).  Dr. John
Weed
>lectured at CCPM during my years as a student ('79-'83) and felt that late
>midstance pronation was caused by lateral ankle/STJ instability in late
>midstance which caused the peroneals to fire in late midstance and cause
STJ
>pronation motion.  I do believe that this mechanism occurs in some
>individuals.  However, I don't think that the body sensing that the 1st MPJ
is
>not going to dorsiflex causes excessive STJ pronation.  It is likely,
however,
>that the body sensing that the 1st MPJ is not going to dorsiflex will
change
>the gait pattern such that ankle joint plantarflexion will become more
limited
>during propulsion.
>
>
>Adductory twist is often associated with late midstance pronation during
>walking gait.  Adductory twist occurs "as a result of any unresolved
pronation
>forces occurring at the time of heel lift" (quotes are used here since this
is
>what was taught to me by either Dr. Chris Smith or Dr. John Marszalec at
>CCPM).  If you want to think of adductory twist as "reducing sagittal plane
>blockage", then I suppose this is OK.  I think of adductory twist as being
an
>event that sometimes does occur and sometimes doesn't occur in the same
>individual, depending on the frictional characteristics between the foot
>and/or shoe and ground, not as a way to reduce "sagittal plane blockage".
>
>Sincerely,
>
>Kevin
>
>***************************************************************************
**
>Kevin A. Kirby, D.P.M.
>Assistant Clinical Professor of Biomechanics
>California College of Podiatric Medicine
>
>Private Practice:
>
>2626 N Street
>Sacramento, CA  95816
>Voice:  (916) 456-4768   Fax:  (916) 451-6014
>***************************************************************************
**
>



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