In a message dated 26/05/99 05:41:42 GMT, Eric writes:

<< Trevor asked.
 >  Measured statically or dynamically ?
 >

 Measured statically.  I think that static measurements, in this case, would
 apply to dynamic gait.  >>

I am sorry Eric but I have to disagree with you big time here. The method of
calculation of the CoP means that the dynamic and static situations do not
automatically correlate. Infact, the CoP only has limited use dynamically
because it can be skewed quite easily.

 I forgot to mention the reason that I brought the center of pressure up.
 Steve mentioned the deformability of the heel and then, If I remember right,
 said something about a negative non weightbearing cast not necessarily
 correlating with the shape of the weight bearing heel.  This becomes
 important if you think an orthosis works by cupping/gripping of the
 calcaneus.  Is the weight bearing heel (on top of the orthosis) correctly
 cupped by an orthosis made from a non weight bearing cast?

 However, the shape of the heel cup may effect function by shifting the
center
 of pressure on the heel.  (Medial heel skive = varus wedge)  We are getting
 away from rigid body mechanics and moving to deformable body mechanics
 (calcaneal fat pads).  The change in center of pressure under a deformable
 body is just the same as the change under a rigid body in terms of effects
on
 joint axes.  So, the shape of the heel cup is important.

 Regards,  Eric Fulle >>


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