Not sure how one can measure strain with kinematic markers. I couldn't see the link you posted Ian. Is it some kinid of elongation/cross sectional are type formula?
Just out of interest, how do they get the data when the patient has shoes on with the SCO inside. Where are the reflective markers?
Am I missing something here
They cut holes in the shoes around the markers and calculated strain by noting the change in arch morphology i.e the arch height to arch length. They made the assumption that the action of the hallux windlass was not changed during the various conditions and the change in length between the assumed origin at calc and virtual insertion at the 1st mpj represented the PF strain, where strain = change in length.
I feel if they had examined the action of the hallux as well then they would have had a better estimation of the PF strain in the various conditions.
The structural characteristics of the shoe are obviously severely comprimised therefore not being a true representation of the orthosis-shoe complex.
Conclusions:
A semi-custom moulded orthotic does not control rearfoot, shank, or arch
deformation but does, however, reduce plantar fascia strain compared to walking
without an orthoses.
Who would have thought heating up a pre-made EVA device and getting sometime to stand on it in normal weightbearing stance would not control anything? :eek:
Exactly.
Unless hallux/digital plantarflexion is accounted for, then the plantar fascial strain will be signficantly over-estimated.
Hallux plantarflexion is what occurs in functional hallux limitus and, thus, the characteristic plantar hallux pressure readings in late midstance.