Anyone who might have read my last few posts will be aware that my experimental equipment consists of a half empty bottle of HP sauce and a water filled surgical glove . This is more of the same !

The post above mentions a paper , very recently published by Hornet and Zelik , which looks at soft tissue work in the early stance of walking .

The post also raises the question of whether the tissues between the bony arch of the foot and the plantar fascia are compressed during gait and so contribute to soft tissue work .

So let's take the surgical glove, adapt it ,and use it to demonstrate tissue compression between the bony arch and the foot .

Take the glove ,empty it of water and tie off the fingers . Now turn it inside out and fill it again with water . Now tie off the top of the glove so that you have a small water filled sphere .
Next , place your cupped hand ,palm down , on a table . The lateral border of the hand lies flat on the table but the medial aspect will form an arch analogous to the medial arch of the foot .

Now place the water filled sphere under the arch /cupped hand , then press down to represent the lowering of the bony arch of the foot during weight acceptance during gait . You will notice that the sphere is compressed between the hand and the table (analogous to the plantar fascia ) and so it bulges inwards . Now place your free hand so that it stops the water filled sphere from bulging inwards ( this hand represents the medial part of the plantar fascia ) .You can appreciate how the water trapped in the glove is now pressurized as the cupped hand is pressed down .

Note ; in the case of the foot this system will not prevent the foot from pronating as the bony arch and the fascia will lower towards the ground as part of the same unit . Instead the intrinsics will act as
(1) a pressurized core reducing shear forces between the components of the bony arch
(2) an energy sump (soft tissue work )
(3) a pump for moving blood out of the plantar venous plexus

The intrinsic can of course do all of the above whilst at the same time acting to shorten the foot or reduce pronation , if they contract with sufficient force . The mechanism by which these muscles can contract whilst under transverse pressure is explained in this thread .(below )

Any thoughts ?

Hydraulically discrete fascicles in skeletal muscle [Archive ...

13 Feb 2016 - 2 posts - ‎1 author
If the perimysium is sufficiently impermeable then might it be possible that each fascicle is able to function as a hydraulically discrete unit with ...