Hi all,
Kevin M. wrote:

>  Eric Wrote:
>You wrote:Kevin, I'm not sure what you are saying. The original post was
>about how
>hip joint moments could create a supination moment at the STJ. My point
>was that the tension in the IT band is predominantly vertical. There would
>have to be horizontal tension to resist transverse plane rotation at the
>knee.
>
>  Kevin M. Replied



>The IT band is a conduit for force.  A link in the kinetic chain, if you
>will.  Viewing the thickest fibers from the tensor to the tibial insertion
>only might lead one to conclude that tension in the IT band is
>predominately vertical.
>
>An individual with only moderate muscle mass and a normal Q-angle may have
>an IT band that diverges 10 degrees or more from the gravity vector.  The
>origin and insertion of the IT band are continuous with the strong fascial
>plane that extends from head to toe and invaginates all compartments
>including the erectors of the spine, and the lower extremity.  Force
>transfer that terminates at the toes is a sum all forces transfered
>through the kinetic chain - in all allowable pathways.  In short, viewing
>simple origin-insertion action for a fascial component negates vector
>sums.  Include the other components and IT band tension can hardly be
>considered vertical.  All of this alludes to the original question by
>suggesting a direct connection between the hip and foot.
>

Kevin, would you describe the vector sums for the IT band at the knee.  I'm
still not seeing your argument.

Eric Wrote:
>You wrote:I'm not seeing it. Hicks described something similar many years
>ago where
>increased tension in the Achilles tendon, shifting ground reaction force,
>distally, would increase tension in the plantar fascia. Are you sure this
>is not the mechanism causing increased tension in the fascia.
>

Kevin M. replied

>The pathways described above either insert on the calcaneus or use it as a
>pulley on the way to the forefoot.  I have taken careful note of this on
>every dissection I have done recently.  In every case the soleus,
>achilles, and fascia are continuous via thick connecting
>fibers.  Typically, the fascia begins to narrow with the gastroc,
>converging with the fascial planes that produce the posterior
>compartments.  The soleus begins to produce the thick fibers mentioned
>shortly after the gastroc terminates.  These fibers extend deep into the
>soleus and run obliquely and downward.  The effect?  Muscle contraction
>anywhere from the gluts distal produces tension in the fascial
>complex.  (This should clarify my earlier statement concerning hydrostatic
>pressure "stiffening" the fascia during muscle contraction as well.)
>

Eric Replies:
The fascia does not use the calcaneus as a pulley.  If it were a pulley
then the fascia would have to slide over the calcaneus.  The fibers are
firmly attached to the calcaneus.  You may be able to see fibers that run
continuously from posterior leg to plantar arch, but the deep fibers attach
to the bone and do not allow sliding.

Now, I would agree that tension in the Achilles tendon will tend to shift
ground reactive force anteriorly, which Hicks has shown will increase
tension in the fascia, because there is an increased bending moment on the
foot.  However, this is not the same as saying that the calcaneus acts as a
pulley and that tension in the Achilles directly increases tension in the
plantar fascia.

This whole body continuous fascia idea has problems because of this lack of
sliding over the attachment to bones.  Contracting a neck muscle will not
increase tension in the fascia.  Yes there are kinetic connections, but
they are more likely mediated by relative muscular activity and the
CNS.  It just makes sense that the body would have  individual control of
all the joints and not have a hard wired mechanical link from head to toe
that would cause an unavoidable change in the foot from a required neck
movement, or vice versa.  Sometimes you need to duck your head when you
walk and other times you don't.


>This brings me back to my original question to Kevin K.  How does
>abductory twist fit into all of this?  I am not sure I understand the
>definition.
>

Abductory twist: At heel lift in gait, there is an abduction motion of the
foot in the frontal plane.  However, this motion is accomplished by the
heel moving medially and the forefoot spinning on the ground. What was your
question?



Cheers,

Eric Fuller

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