Functional differences between the hallux and lesser toes during the single leg stance

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Clarification of functional differences between the hallux and lesser toes during the single leg stance: immediate effects of conditioning contraction of the toe plantar flexion muscles
Junya Saeki, Michio Tojima, Suguru Torii
Journal of Physical Therapy Science Vol. 27 (2015) No. 9 September p. 2701-2704

 

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pretty interesting study

need to have a read of it again, postural sway velocity read many times before coffee :santa2:

But

would love Howard Dananberg?s thoughts

Gait related lower back pain

Because if if my Coffee less brain is reading correctly increasing the planterflexion moment or increasing the dorsiflexion stiffiness at the 1st mtp leads to less postural sway velocity which then leads to question re Sagital plane theory

anyways off for coffee and fix a device with a reverse mortons extension

 

I'm not sure that the authors have a good understanding of the physics of postural sway. They equate center of pressure excrusion with postural sway. Winter clearly showed that they are related but are different things. There is motion of center of mass and there is the location of the center of pressure. These are different things and should not be considered the same.

Single leg standing is a relatively difficult task (and a good clinical test for a lot of different things). As the body sways over the foot the center of mass will move relative to the center of pressure under the foot. The task is similar to balancing the tip of a pencil on your finger. You have to keep moving your finger to prevent the pencil from falling down. In single leg standing, you have to move the center of pressure under the foot to keep the whole body from falling over. The force of gravity acting on the center of mass and the ground reaction force, acting at the center of pressure can create a force couple cause an angular acceleration of the body. If the body starts to rotate forward, the person has to shift the center of pressure more anterior than the center of mass to create a force couple that will create a moment in the direction of falling over backwards. This will slow the fall. It is very hard to get the center of pressure to sit directly under the center of mass. This illustrates the difference, and the correlation of the center of pressure and postural sway.

The authors were correct in noting that muscular effort is required to keep the sway from leading to falling over. However there is a difference between balancing over the ankle and balancing over the foot. To balance over the foot you need to have ankle joint moments. The flexors of the toes, that were looked at in the study, do not contribute significantly to ankle moments. The study completely ignores the anterior tibial and gastorc soleus as contributors to center of pressure location change. Those muscles are much more important as they contribute significant ankle joint moments.

Eric

 

Sorry, I was posting quickly and left out the most important point.

They cannot make that conclusion when they ignore the anterior tibial and gastroc/soleus muscles.

Eric

 

Hola a todos!
Soy estudiante de podologia de 3? curso y me acabo de incorporar al foro.
Estoy seguro de que me servir? de mucha utilidad conocer vuestras ideas y comentarios.

Recibid un cordial saludo.

 

Hola a todos!
Soy estudiante de podologia de 3? curso y me acabo de incorporar a este foro.
Estoy seguro de que me servir? de mucha utilidad conocer vuestras ideas y comentarios.

Recibid un cordial saludo.