I have read that tension in the plantar fascia translates into downward pressure from the digits onto the ground and I also believe that the plantar fascia helps support the medial longitudinal arch of the foot .
Members do not see these Ads. Sign Up.
However, what if their is no ground under the toes but the toes overhang a small drop ? Does that mean that the plantar fascia can offer less support for the medial arch ?
-
-
You can see that if you stand on an edge of something with the toes hanging over the end; the toes plantarflex below the horizontal surface -
So if an individual is wearing shoes with a toe spring and the area under the toes yields and bends downwards under pressure, can that affect tension in the plantar fascia and so pronation .
-
The reverse windlass in action
-
-
-
Moving proximal to distal the medial aspect of the plantar fascia can be said to attach at the heel then pass forwards and attach to the base of the hallux via the plantar plate .
Leaving aside the extensibility of the PF, when an unshod foot accepts weight the PF, of length x cm, comes under tension and helps support the arch and resist pronation .
In a shoe with a pliable toe spring, the pressure under the hallux will depress the toe spring as the toes plantarflex below the horizontal . This plantar flexion will bring the points of attachment of the PF closer together meaning that the medial longitudinal arch must flatten further before a given tension is reaching in the PF .
If the points of attachment of the PF move 2mm closer together, will that affect pronation extent and timing ? Worth looking at perhaps . -
-
In light of Welte et al ,where the researchers found that the toes rapidly plantar flex during weight acceptance, loading the plantar ligaments in preference to the PF, toe springs that holds the toes in a plantarflexed position could be problematic .
Some shoes, particularly those with a large heel drop and an inner design that slants to toes upwards ,might not allow rapid plantarflexion of the toes leading to abnormally high levels of loading in the plantar fascia and less than normal in the plantar ligaments .
Could this set of circumstances trigger plantar heel pain? -
-
We also need to be cautious and accurate with terminology here: toes may “rapidly plantarflex” from a dorsiflexed position but that does not necessarily mean they are plantarflexed at the end of that motion. -
One in which the toes and proximal part of the foot start of on the same horizontal plane and then the toes compress the toe spring during weight acceptance thus becoming plantar flexed, and another in which the toes are held in a dorsiflexed position during weight acceptance and are prevented from moving onto the same horizontal plane as the rest of the foot by the rigidity of the toe spring .
Some running shoes hold the toes in a markedly dorsiflexed position and have a construction that looks like it would hold them there during loading at weight acceptance. If the toes are stuck in a dorsiflexed position then the PF might be subject to excessive loading.
So depending on construction, toe springs might promote excessive pronation by allowing toe plantar flexion beyond the horizontal or hold the toes in a dorsiflexed position causing excessive loading of the PF . -
We had a discussion of dorsiflexion of the hallux when we talked about the cluffy wedge.
https://podiatryarena.com/index.php?threads/pre-loading-the-hallux.3651/ -
-
-
“Without altering the pressure under the ball of the foot ?”
Pressure is dynamic: step to step variation, footwear variation, surface variation: viva variation!!!! -
-
-
-
With a rocker that lifts off of the ground just proximal to the metatarsal heads: To get the center of pressure anterior to this point, there would have to be almost no weight on the heel. In most situations the excursion of the center of pressure is not this not this much. For most people, the rocker tip won't cause balance problems. For those with balance problems, with larger excursions of the center of pressure, rocker tip shoes would be more unstable. -
-
-
The body is very good at feedback and I believe it entirely plausible that over time the toe flexors could simple put in less effort since less is required .
Moving from a normal shoe to a minimal shoe saw toe flexor strength increase by 57% in one recent study and I think this has little to do with cushioning or medial arch support and much more to do with toe springs and, most particularly, sole/shoe/foot passive stiffness once the system is dorsiflexed.
Last edited: Mar 10, 2022
Loading...
- Similar Threads - plantar fascia pressure
-
- Replies:
- 2
- Views:
- 818
-
- Replies:
- 1
- Views:
- 467
-
- Replies:
- 0
- Views:
- 789
-
- Replies:
- 1
- Views:
- 1,019
-
- Replies:
- 6
- Views:
- 2,883
-
- Replies:
- 9
- Views:
- 3,008
-
- Replies:
- 12
- Views:
- 3,393