Very recently a paper was produced by a group of searchers looking into the windlass mechanism . The paper was -
Influence of the windlass mechanism on arch-spring mechanics during dynamic foot arch deformation.
Welte L, Kelly LA, Lichtwark GA, Rainbow MJ.
J R Soc Interface. 2018 Aug;15(145). pii: 20180270. doi: 10.1098/rsif.2018.0270.
Here is a quotation from the paper .
"The purpose of this investigation was to understand the interaction between the windlass and arch-spring mechanisms, by engaging the windlass through MTPJ dorsiflexion, and investigating the effects on arch energetics during a dynamic compression. We hypothesized that MTPJ dorsiflexion would pre-tension the plantar fascia and stiffen the arch. However, in contrast to our hypothesis, the engagement of the windlass mechanism reduced the stiffness of the arch and increased energy absorption and dissipation. The effect of MTPJ dorsiflexion therefore has the potential to affect locomotion by altering the mechanical energy profile within the foot. "
So the researchers did not find what they thought they would .
They forward an explanation of their results as follows
-
" The windlass did, however, modulate the energetics of the arch during dynamic loading. When the windlass mechanism was engaged, the arch was shortened significantly, which probably placed other tissues crossing the arch closer to their resting length. The arch could therefore go through a greater excursion due to the nonlinear elastic properties of the arch-spanning tissues. This would functionally reduce the bulk stiffness of the arch and lead to greater elongation, and consequently facilitate greater energy absorption and dissipation during cyclic loading of the foot
"
However , an alternative explanation might be that
when the toes are plantarflexed , and force is applied down through the foot as shown in the experimental
set up , the tissues of the foot between fascia and bony arch resist compression . When the toes are dorsiflexed through the windlass mechanism , the volume of space between the bony arch and plantar fascia is increased allowing
the foot to compress more easily (reduced stiffness ) .
I feel this is a more likely explanation .
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