Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

Max arch height in foot orthoses test

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Simon Spooner, Mar 28, 2012.

  1. Members do not see these Ads. Sign Up.
    I came across this whilst researching for a lecture:

    In this paper Rose refers to a weightbearing casting technique in which the hallux is fully dorsiflexed (not dissimilar to a MASS cast of the foot). Strikes me that the maximal medial longitudinal arch height (and profile) of a foot orthosis should not exceed that exhibited by the foot in this position- what say you?
  2. Admin2

    Admin2 Administrator Staff Member

  3. Hi Simon,

    I have a number of customers using this method of casting in foam and on laser scanners, it is described by all of them as "The Reverse Windlass Casting Technique".

    The majority are Physiotherapists with requests for a close contact shell to be designed and manufactured around this Cast.

    Checking the past 40 orders like this i can say that the typical peak arch height upon the devices is in the region of 35mm, the contour of a device manufactured in that manner is more distinct. Average neutral based casts etc with 2mm arch fill are in at around 29mm.

    It seems that this mentioned method of capture may be getting passed down somewhere?? Although they have used it for up-to 8-9 years and i do not recall MASS initial start date:confused:

    There is a definite tendency towards non tolerance within a small margin of error when designing and making the device to a 2mm cast correction. But we do not get these devices rejected and the method seems repeatable on a daily clinical basis.

    As an example two clinics tend to both foam and scanned weight bearing of each patient, the reproduced foot capture is incredibly similar and reproducible when compared and the resulting device is as close as i believe possible. They do all tend to arrive 2 - 3 degrees inverted unless a lot of care is taken.

    The device contour for the medial arch tends towards a more concave shape with this method of capture, cast fill and so manufacture. The peak of the arch is high, yet it almost wraps around the foot, as such this likely aids conformity of use.

    I did have a case recently with a request for a device from this cast style, with a further request for 4 degrees inversion to the balance. Despite advising against....the device proved untenable.

    Back to your question (sorry for the ramble) in daily practice... i reckon that If the device medial profile height and the contour of the device is comfortable and well tolerated, and increasing the height of the medial profile is required clinically to gain relief of symptoms, then fine.

    As the force being exerted is appropriate to the requirement. But i have to say that i personally have never issued devices of that sort of height consistently, but the profile differs considerably when using that capture method.

    So to sum... maybe (hedging) based upon the fact that once maximum Z axis correction is achieved we are likely better of posting the frontal plane and avoiding sore arches and angry customers?

    And maybe it could fit the sort of common sense height that will hurt if we go past.

    Mechanically...i don't know at all if it makes sense to go past the height. I am to tired for a thought experiment style reply tonight!

    Of course Equilibrium and spatial orientation of the joint axis will come into play with regards to advisable arch contour in particular. And also if more can be gained in terms of applied action/force from arch height vs contour vs posting and modifications/inversions and skives.

    But definitely not convinced of any set or given arbitrary parameters that fits all of patients, prefer to think about how to help, as we all do.

    Going to struggle with sleep until i re-visit this :craig:

  4. efuller

    efuller MVP

    I certainly agree that it should not go higher than that. Considering how much a MASS orthotic hurt my own feet, I would say that there are at least some feet that should not go even that high.

  5. drsha

    drsha Banned

    Wow. When discussing arch height, you're discussing Architecture and Structure.
    No engineering or major physics here, just Architecture.

    Using Erics poor architectural knowledge, there should be some feet that can tolerate even higher. Bad science.

    My sense is that we are after what I call Optimal Functional Position for casting and casting position is Structural and Architectural my colleagues.

    I suggest you correlate your arch height imaginings with EMG studies that would show at what arch height the muscle engines of the foot are functioning maximally, then you're really onto something. Muscle being trainable. feet strengthening. Where some of us have been for years, right Ed?

    The arch height for any individual that provides maximal muscle engine performance efficiently would be the ideal position for an orthotic shell to start as. Optimal Functional Position (OFP)

    IMHO, OFP is mostly higher than STJ Neutral (the difference between 29 degrees and 36 degrees perhaps).
    I theorize that Rootian Biomechanics need upgrading in this direction.

    This height should be determined as Vault Height and not Arch height (MLA) IMHO.
    It doesn't effect TS at all.

  6. efuller

    efuller MVP

    Dennis, if your going to put my name and the term "bad science" in the same paragraph, could you at least explain the connection?

    Dennis, as much as you seem to want it to not be so, physics still happens in architecture. Just because you choose to rename an arch a vault, physics still explains why the arch is able to support, or not support, a load.

    Step one is think up the idea that there is an optimal functional position for feet. Step 2 is to define that position. Step 3 is to test assumptions based on that definition. Dennis, how do you define the optimal foot position.

    Ok we're on to step 2. There is a problem. How do you define that the muscle engines are functioning maximally? Is functioning maximally a good thing? Dennis what engineering tests would you do to assess if the muscles are functioning efficiently?

    Dennis, these last few sentences are a good example of why your reputation has become what it is on the arena. By the way, what's the difference between arch height and vault height.

  7. drsha

    drsha Banned

    When you state:
    The fact that a MASS device hurt your own feet does not allow you to draw a conclusion that "it should not go higher than that.
    Your very reasoning would follow that there must be some feet that could go higher.
    Sorry if bad science was incorrect but your expert chair on The Arena would have some of us less skilled than you assume that it was scientifically accurate when it was no more than opinion (something you do not allow me to have).

    I add additional vaulting to the shells of feet that I have previously cast as their arch height improves. (anecdotal).

    Eric, as much as you seem to want it to not be so, architecture still happens in physics.
    Hey, lets team up.

    Eric, There is no problem unless you want to make it one.
    I conceived a research hypothesis and you question me as if it already was published.

    I will take the time from my work (as you are doing from yours, I assume) to do the same to every new conception you make until you cut me some slack, I promise.
    Can't we both breath fresh air on The Arena?

    You know as much about Foot Centering as I do, you tell us.

    By the way, what's the difference between tissue stress to "preventing compensation for deformities" as in the Rootian Theory?

  8. David Wedemeyer

    David Wedemeyer Well-Known Member

    Anecdotal to say the least, where is your proof that raising the arch height of a foot orthosis produces a permanent change in the arch of the foot when the device is removed? It is predictable, repeatable, reliable? EBM level = anecdotal when you seek to hold all others accountable to EBM?

    Dennis keep conveniently forgetting that numerous studies show that arch height and thus "architecture" are not predictive of pathology. How can he therefore assume that "vaulting" (a term as Simon pointed out in another thread is not a new or unique concept that Dennis can claim and yet he appears to be :rolleyes:) produces any of the benefits that you proclaim?

    There is a reason that ALL of your posts are met with skepticism and it's not us, its you.

    We know very little about Foot Centering because you cannot validate it, explain it, correlate it with pathology and there is zero evidence or EBM publised for it.
  9. efuller

    efuller MVP

    I made the assumption that people on the arena are capable of understanding the qualifier "some feet".

    Dennis, I never said it didn't. What I have been saying is architecture is just descriptive. Physics explains.

    Dennis, you are already selling the idea. That is the problem. You've taken the idea of optimal foot position (from Root et al) and haven't even bothered to write out criteria that would define that position before you are selling the idea. Dennis, this is why you are attacked on the arena. You are trying to sell something that you haven't even explained yet.

    There isn't any difference. Dennis, stop trying to make it sound like there is.

    Preventing compensation for deformities is a more positional approach to foot biomechanics. The compensation is a change in position. Tissue stress doesn't necessarily have to change position, but the goal is to change the stress on anatomical structures. Any further questions, Dennis?

  10. MJJ

    MJJ Active Member

    This really sounds quite dissimilar to a MASS cast to me. MASS is not fully weightbearing and is done without dorsiflexing the hallux.
  11. drsha

    drsha Banned

    referring to, constituting, or grounded in matters of observation or experience <the descriptive basis of science.
    I disagree that architecture is purely desciptive in that it is foundational to any engineering project.
    Structural soundness in any system that is eventually mechanized must be maintained and repaired over time and through clinical trial and research the structure can be improved upon rather than be accepted as a constant.

    At Ryerson College in Canada there exists a model that perhaps we can aspire to.
    They have a Faculty Division of Engineering, Architecture and Science (FEAS).

    The engineering and architectural science students remain grouped as one faculty.

    Colin Ripley, the architectural science graduate program director states “Architecture as a design discipline is a different culture than the engineering discipline. We do different work, research and disseminate in different ways. Engineers don’t understand our culture and there’s no reason they should".

    They have taken a leap of faith and opened up the doors to intertwining both sciences. Why can't we?

    Dennis, you are already selling the idea. You've taken the idea of optimal foot position (from Root et al) and haven't even bothered to write out criteria that would define that position before you are selling the idea. You are trying to sell something that you haven't even explained yet.[Quote}
    I disagree once again.
    I have explained my work to tens of thousands around the world who using the language of Foot Centering not only understand but tell me that its the most understandable form of functional lower extremity biomechanics they have been exposed to.
    I have put in print on these very pages that the flexible rearfoot type is treated with rearfoot frontal plane correction technique and rearfoot vaulting technique.
    You rejected that as an explanation because of language difficulties.
    Until I learned moments, stiffness, friction, torque, etc I couldn't understand or participate in your work. Now I sense that I do pretty well as I can teach it to others.
    I don't owe any of your queries any more than I have given you.

    No matter what, it doesn't justify the ATTACK (notice you use the word "ATTACK") or the vicious and underhanded means at which you perform your military operations on The Arena.

    Unlike some amazingly ignorant fantasies and interpretations of my work that are being seeded here on The Arena,, Foot Centering involves both schools of biomechanics. It is a blend of all that is good, biomechanically.

    So please, in the future, consider this as my definition of Foot Centering as of 04/10/2012 (as it will continue to morph over time).

    "The Foot Centering Theory of Structure and Function combines both architectural and engineering science and principles in a complimentary manner. This blend of both sciences has a starting platform called Functional Foot Typing for preventing and treating compensation for deformities as a positional approach to foot biomechanics (Structure) and then applies changes in the stress on anatomical structures to mechanize them most efficiently, effectively and balanced utilizing both ORF and MERF resources (Function)".

  12. No. Just no.

    Please stop derailing perfectly good threads. Not everything is the world is about you and your work.
  13. drsha

    drsha Banned


    I will try but in doing so, I will start some threads of my own and all I ask in return is that The Arena doesn't derail them.

    Just don't visit them.

    Then we have a plan for a brighter future.

    How 'bout it?

  14. Can't promise i won't visit. But if I do, i'll stay on topic.

    Sounds like a plan

Share This Page