Cushioned shoes and foot stiffness.

Members do not see these Ads. Sign Up.

Do shoes with a lot of cushioning under the ball of the foot negatively affect foot stiffness? I think they probably do. A lot of cushioning may reduce met head movement in the transverse plane.

 

How high can you jump in shoes with a lot of cushioning under the ball of the foot ? Probably not as high as you can with a more solid take off platform, both from the point of view of energy absorption and foot stiffness through toe off.

 

Foot strengthening can improve vertical jumping, but how? During a vertical jump the met heads move relative to each other extending the transverse arch distally . They move together mediolaterally and apart anteroposteriorly . Foot strengthening improves the function of the adductor hallucis which assists in this action giving a stiffer foot at take off.

The adductor hallucis both flexes the toes and causes adduction . Toe flexion exercises will activate and strengthen the adductor.

 

Gerrard, you are getting the right answer for the wrong reason. Increased tension in the AP direction on the plantar foot (abductor or adductor hallucis muscle tension) will increase stiffness. A transverse arch, if it existed, would increase stiffness in the frontal plane and not the sagittal plane. A softer shoe could absorb more energy when it is deformed than a harder shoe and this will reduce energy available for increasing the height of a jump. Don't make it more complicated than it needs to be.

 

Eric, fold a dollar bill transversely and it is stiffened longitudinally.

You don't believe the foot has a transverse arch?

 

I believe that some degree of cushioning is a good thing if you are going to run on concrete, after all, the human foot evolved with cushioning ( fat pads ), for moving on surfaces like compacted soil .

But how do you encourage met head movement in the transverse plan and still have cushioning ?

OESH shoes may have one answer. A comparatively stiff insole with cushioning beneath.

 

The foot does not have a transverse arch. Arch as defined as a structure to support load on top of it and its bottom the arch has contact at either end.

When you fold a piece of paper you are increasing the distance between the part of the paper that is under tension and the part that is under compression. That is where stiffness comes from. The stiffness increases in some directions, but not others.

 

I agree some amount of cushioning is a good thing. There is a tradeoff between comfort and performance.

Why would want to cause met head movement in the transverse plane? That will tend to cause plantar blisters.

One reason the cushioning next to the foot is good is that it reduces plantar pressure under the metatarsal heads. That works best when the cushioning is in direct contact with the foot, not with a rigid layer on top of the cushioning.

 

Would you accept the foot has a medial longitudinal arch ?

I realise that you are a well respected figure within the podiatry community Eric, but believe you have this part completely wrong.

 

Yes. In my windlass paper I described which bones make up this arch. If you believe there is a transverse arch tell me which anatomical structures make up the arch.

What do you base your opinion on?

 

In your opinion, is the medial cuneiform one of the bones that makes up the medial longitudinal arch?

 

Yes

 

Some define the transverse arch thus: "The transverse arch is located in the coronal plane of the foot. It is formed by the metatarsal bases, the cuboid and the three cuneiform bones .

The transverse arch has contact at either end. Laterally, via the cuboid and base of the 5th metatarsal, and mesially via its relationship with the medial longitudinal arch . The medial cuneiform is shared by both arches so you could say the transverse arch rests on the longitudinal medial arch giving it contact at both ends.

 

The load of body weight is supported by the longitudinal arch because the load is applied at the top of the talus. The structures you describe are an arch, but they are not supporting any load. An arch supports a load through compression. The structures you list don't have articulations, between them, that would resist compression.
Eric

 

Are you saying the foot does not flatten transversely during gait when under load?

Also, one common definition of the medial longitudinal arch is



Medial longitudinal arch

The medial longitudinal arch is higher than its lateral counterpart and is visible between the heel of the foot proximally and the medial three metatarsophalangeal joints distally.
Bones

The bones participating in the formation of the arch are the following:

• the medial three metatarsals up to their heads
• the sesamoid bones
• the three cuneiforms
• the navicular
• talus
• calcaneus

So a large part of the transverse arch ,the three cuneiforms, are also part of the longitudinal arch. If the MLA arch supports load then so does the transverse arch as they share many of the same bones.
Are you more on board with the idea of the foot as a half dome? I prefer to see it this way .

I agree that people see the words " distal transverse arch " and imagine the met heads stacked like stones in an arched bridge over a river which of course is not the case.

Do you have any cases of long standing plantar fasciitis on your list?

 

Where do you see flattening in the frontal plane?

You can look at shape or you can look at the forces involved. The premise with which you started this thread was asking about stiffness. What are the forces that create the bending moment on the foot. In what plane do they create the greatest moment. The upward force from the ground acting on the metatarsal heads, the downward force of body weight from the tibia, applied to the talus and the upward pull of the Achilles tendon (or the upward force from the ground acting on the calcaneus.) Draw the free body diagram in the frontal and sagittal planes.

The bending moment is much greater in the sagittal plane. To resist this moment you need tension and compression forces in the anterior posterior direction. These are in the structures in the medial arch and the lateral column. Compression in the bones and tension in the plantar ligaments and the plantar fascia.

The upward force on the met heads is usually on all of the met heads. This spread across all the metatarsal heads provides the medial lateral stability of the longitudinal arch.

 

For example ,along the medial longitudinal arch . As this drops in height you will see the mesial part of the midfoot transverse arch drop since it shares 3 bones with the medial longitudinal arch. The bones of the transverse arch likely move less, relative to each other, than the bones making up the medial longitudinal arch when under load.

load.

This takes us back to the dollar bill and a transverse fold making it stiffer longitudinally .
We have, I think, been over this ground before but I have something new to add.

As you may be aware I manufacture a product called the novabow .

Recently, a fitness instructor with long standing, severe, plantar fasciitis approached me and asked if he could use a novabow to strengthen his foot. The condition had been diagnosed by his GP and had failed to respond to all attempts at treatment including stretching, strengthening, footwear adjustments, rest and even a cortisone injection.

I thought that his condition might improve if he used a novabow for a month or so, but not quickly since the pain was so severe. However , his heel pain , diagnosed by his GP as plantar fasciitis , was complete gone within 48hours . He back to playing 5 aside football within a week.

He said that he felt a stretch across the ball of his foot when using the novabow system and recognised that 24 hours was not enough time for any strengthening aspect to have played a role .

I think the novabow probably mobilized the met heads and allowed then to move properly during gait thus reducing strain on the plantar fascia and or abductor hallucis.

 

Since both arches use the same bones. When the longitudinal arch lowers, the medial arch will lower, does it maintain the same shape in the lower position. You can measure change in first metatarsal declination. You are ignoring the point I made about where load is applied. The transverse arch is not supporting any load because load is applied to the talus.

It depends on which direction the object is loaded.

Take a 2 x 8 piece of lumber. When the 2" side is on the ground, and the board is loaded vertically, it is much stiffer than when the 8" side is on the ground. This is because the distance between the part of the board that is under compression is farther from the part of the board that is under compression. You need a tension /compression force couple to resist bending. Now take a 1/8" x 8" x 8' piece of plywood and load it with the 1/8" side on the ground loaded at either end. If you could prevent a longitudinal fold in the plywood it could support quite a bit of load. This is the advantage you get by folding the dollar bill. If you fold the bill and bring the edges together, it is less stiff than if there is some distance between the edges a "V" shape. You could make the case that it would be stiffer unfolded, if you could prevent it from crumpling. (When compressed by load on the long sides)

 

The proximal transverse arch, probably better described as the transverse curvature, will transmit load to lateral aspect of the foot during weight acceptance and so aids the medial longitudinal arch . It will pretty much maintain its shape because of the nature of bones that comprise it and their relationship to each other .

The transverse curvature needs to be maintained because it increases foot stiffness . During gait, the met head arrangement leads to greater curvature across the met bones giving stiffness. Please see video.

https://youtube.com/shorts/MPTYdPIit_4?si=O6MHIvLFvoMJu2ul

I don't know what you mean.

 

I don't know what you mean. "will transmit load to lateral aspect of the foot during weight acceptance"

 

The longitudinal arch supports load. The medial ,intermediate and lateral cuneiforms are all part of the longitudinal arch and so support load . The lateral cuneiform will transmit load to the cuboid and hence to the lateral aspect of the foot .

It is generally accepted that the met heads move in the transverse plane . Lack of movement might cause blisters and or ulceration esp under met head 2 .

In the picture below you can see the convex shape of the underside of the foot . This stiffens the foot .

Some time ago ,on a related thread, I asked if met head movement in the transverse plane was generally recognized. An arena member gave me a stack of references on the subject demonstrating that such movement has long been recognised .

As far as I am aware I am still the only person arguing that this relative movement, caused by the metatarsal parabola and transverse arch curvature , stiffens the foot. This would generally ring a warning bell for me, but geometry is geometry.

 

Agreed the longitudinal arch supports load. Body weight is not on the transverse arch. The transverse arch, as you have described it, is not supporting load.

 

I've watched many a "rollover process" from an EMED force plate. I can't say that I've ever seen medial lateral movement. You can see proximal to distal movement of the contact point of the metatarsal heads. I would attribute this to the geometry of the metatarsal heads. There is a circular surface at the distal aspect of the metatarsal, and as the heel lifts, the metatarsal "roll ," like a wheel, forward in the sagittal plane. A soft shoe would not impede this movement. Gerry what movement do you feel is impeded by soft shoes.

Gerald, yes shape has a role to play in stiffness. But stiffness is a physics problem, not just a geometry problem. I think I now understand what you are driving at. The stiffness increase is not from the transverse arch, but from supination of the subtalar joint. Structures are stiffer if there is greater distance between the parts that are under compression and under tension. Example: the 2 x 8 piece of lumber when set on its 2" side versus its 8" side in response to a vertical load. With supination of the subtalar joint, the talar head is more on top of the calcaneus and this increases the dorsal plantar distance from compression in the talonavicular joint and tension in the plantar fascia and long plantar ligament. Supination of the subtalar joint will change the orientation of the "transverse" arch, but it is not the transverse arch that contributes to stiffness. With supination of the STJ there will be a tendency to lift the first met off of the ground and to keep the first met on the ground the first ray needs to plantar flex. In the picture you posted, it appears the "transverse arch you are pointing to is from First ray plantar flexion. The arrow in the picture is pointing to an arch at the level of the metatarsal heads, not at where you have been describing the transverse arch.

 

Did you mean an EMED pressure platform ( also called pressure mat) ? A force plate is an entirely different measuring device , although perhaps there are a few hybrids about.

Did you mean to say this previously ? I ask because if the second metatarsal extends proximally further than the others when a foot is flat of the ground, then when the foot " tips up " (heel off) ,won't the the 2nd met head have contact with the ground ( via plantar plate etc ) whilst the others are left "high and dry" as it were. To get what you suggest requires that the met heads move relative to each other in the transverse plane.

You can model this with your hand .

 

You are correct the EMED device that I used measured pressure and pressure over the 0.5 sq cm sensors could be summed to produce a vertical force value.

Did you mean to refer to the distal protrusion of the 2nd met? Peter Cavanagh did a study of x-ray measurements versus pressure and found the longer the second met was distally, the greater the plantar pressure on the 2nd met head.

In my viewing of roll over processes I cannot ever recall a single met head bearing all the weight. Maybe there was right before lift off, but by then there was very little force on the foot. The high force on the 2nd metatarsal could cause it to bend more than the other metatarsals and this could explain the neighboring metatarsals still bearing weight. This bending would be seen in sagittal and frontal planes, but not in the transverse plane.

 

Sure, but the correct term is pressure platform/mat, not force plate.

Yes, my mistake, I wrote "proximally" when I meant "distally".

It is my belief that the metatarsal parabola exists so that during gait, as the heel lifts, adjacent met heads move apart anteroposteriorly and together mediolaterally, extending and exaggerating the transverse arch distally to stiffen the foot.
Why else would it be present? Surely not to concentrate forces on the 2nd metatarsal causing it to bend more than the other metatarsals.

 

Would you change your belief if a medial to lateral shift of metatarsals is not seen?

 

I would expect to see the most noticeable metatarsal movement anteroposteriorly.

This might be especially noticeable in those who are habitually unshod, barefoot athletes like judo players , or in those who practice barefoot, hard surface, single leg calf raises, such as members of ballet Australia.

When you do a calf raise on a hard surface the met heads must move or the distally extended 2nd met will bear all the weight and this does not happen in a healthy foot. It is my belief that the calf raises used so successfully by ballet Australia encourage met head movement and foot stiffening . If you do a calf raise on a soft surface the met heads can move apart vertically and this is what soft shoes encourage.

When I do calf raises on a hard surface I can see the ends of my big toe and 2nd toe move further apart anteroposteiorly. There is also a noticeable narrowing of my foot which I could video if you really wanted to see it.

I have been doing "The Australians " , Dr Mayes's exercises, for some time now and no longer feel excessive pressure under met head 2 when doing calf raises but rather the load is spread across the ball of my foot.

What purpose do you think the metatarsal parabola serves ?

 

Note to add to the above post . Single leg calf raises may not be good idea for everyone . When I do them, I do them slowly next to a support surface to prevent falls. I think Susan Mayes recommends a particular rhythm but I can remember exactly what it is .

 

How does a metatarsal move in the a-p direction. Motion relative to what? The bases of the metatarsal aren't going anywhere relative to the bones proximal to them. The first metatarsal is capable of plantar flexing and this may look like a-p motion of the first metatarsal in the transverse plane. Is first metatarsal motion creating what you are claiming the transverse arch is?

The relative lengths of the metatarsals is a product of evolution. It doesn't serve a purpose. The shape of the metatarsals is adequate to enable people to reach childbearing age.

 

Nobody said anything about the met bases moving. I believe you are being disingenuous here.

If the relative lengths of the metatarsals serves no purpose then why is the parabola present in almost every human foot? If relative length served no purpose, then surely we would see a more random pattern of relative lengths in the population.

In the past few million years, reaching child bearing age was a very tricky business for our ancestors. I think you may be underestimating the importance of the foot for bipeds and their survival rates in a pretty unforgiving world.