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Tried searching but no success.
It was taught that a sole should only bend, in sagittal plane, at the metatarsophalangeal joint region.
Admin any threads i can study.
Any references.
Any opinion from the pedorthotists?
Thanks.

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Hi,

I can't help, but I'm interested.

What was your original ref - ie where was it taught, and by whom?

Cheers,

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Old guys rule!

http://www.podiatry-arena.com/podiat...ead.php?t=3990

http://www.staffs.ac.uk/isb-fw/ISBFo...gStiffness.pdf

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"My mission drive is to open up my eyes, 'cause the wicked lies and all the sh!te you say..." http://www.youtube.com/watch?v=V4NW5S1UTPQ

"Science is the antidote to the poison of enthusiasm and superstition."

Mark,

I was taught in my CPed course that an appropriate commercial shoe should only flex at the MTP's joints, which would be in the sagittal plane. Therapeutic shoes have this feature, as you know carbon and metal plates can be fitted to ensure frontal plane motion of the shoe is minimized or negated. I know that there is a reference somewhere in my pedorthic reference manuals and books, if you truly need it I will look. What I could find online with a quick search:

http://cobblerscorner1.com/faq/

6) The shoes should not bend at the arch area, if it does, the shoe WILL NOT effectively support the arches of your feet.

8) The shoes should have flex grooves on the soles from the ball area of the shoes forward. This will allow your feet to flex naturally.

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"If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance." - Orville Wright

David G. Wedemeyer, D.C., C.Ped.

Maybe, with the exception of rocker soles ! S. Hutchins et al. / The Foot 19 (2009) 165–170, http://www.ncbi.nlm.nih.gov/pubmed/20307470

Also, it could be of interest the sole torsion properties which I think could be related to frontal plane stiffness of the sole. One paper is : C. Morio et al.The influence of footwear on foot motion during walking and running, Journal of Biomechanics 42 (2009) http://www.google.ro/url?sa=t&rct=j&...LjrgQZYYfkVSQg

Nigg's book "Biomechanics of Sport Shoes" contain some data about sole torsion
Hope these helps !
Daniel

I am enjoying this discussion on sagital plane stiffness of the forefoot with great interest.

However, shouldn't we also be considering the importance of sagital plane stiffness of the rearfoot?

Dennis

I found this article related to the thread's subject :
"Shoe midsole longitudinal bending stiffness and running economy, joint energy, and EMG."
http://www.ncbi.nlm.nih.gov/pubmed/16540846

Daniel

Hi Guys,
I spent 15 yrs fitting boots and shoes for sking and trekking etc before I did the pod degree. We spent a great deal of time measuring and comparing feet and boots and shoes and keeping notes about who bought what etc. We began to offer a money back quarranty in 1988 for ski and walk boots...this tends to sharpen up your game, because getting it wrong starts to cost money. I never did any controlled studies.....but you can't help but notice stuff when you pay attention to all the details.
There is an interface of dynamic function between feet and foot wear and the nature and function of this interface is pretty much what determines if a piece of foot wear works for its designed functional purpose with a particular foot.

Every detail you can observe is relevant. Every movement, every force, torque, impact, unweighted moment has an effect. Every aspect of the anatomy of the foot, and every aspect of the materials, design and construction of the footwear is a factor in the total result.

Whether you can measure and isolate any particular factor among all these things is another question entirely. Many of these things cannot be measured and equipment to measure alot of these things does not exist yet....that I am aware of anyway.

A few things I believe from observation include.....a lax foot type that changes shape a great deal between weighted and unweighted will have trouble being comfortable in a stiffer shoe/boot until the foot itself is stabilized via orthoses, which greatly decreases the degree of change in the foot and therefor the amount of shear force generated between the foot and footwear.

Rigid foot types have more trouble adapting to boots and the nature of the fit becomes more important.
A sole that twists too easily will not function as well in more rugged applications.
A mismatch of sole rigidity and upper strength/rigidity causes trouble.

Change the nature of the sole and you change how much force you can apply with the boot in situations of dynamic balance.

A fascinating field and I've never got sick of it....but now working as a pretty standard rural practice pod I don't get much time looking at esoteric foot wear issues.

regards Phill Carter