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Pronation:Busting Some Myths with Disruptive Technology

Discussion in 'Biomechanics, Sports and Foot orthoses' started by drsha, May 11, 2012.

  1. drsha

    drsha Banned

    Members do not see these Ads. Sign Up.
    Null Hypothesis:

    Current technology has implanted seeds that
    1. pronation is bad
    2. pronation means a collapse at the STJ.


    Historically, the word pronation has become related to:
    1. Something bad
    2. Existing within the Subtalar Joint alone
    3. Dominating on the frontal plane of the subtalar joint

    This has placed an unnecessary bias in the direction of the STJ and its pronatory motion (especially the frontal plane) as culpable and treatable in most biomechanical diagnosis and treatment paradigms until now.

    Pronation is one of the tri-plane movements of any joint within the biomechanical postural complex when it does not live exactly on one of the three body planes.
    Supination is another, circumduction, yet another.

    Planal dominance and the establishment of ORF's and MERF's can be defined and developed joint by joint with, essentially, no one joint within the posture dominating.

    These myths need to be busted and it will take a Destructive Technology to accomplish that.

    When looking at Rootian Biomechanics and the modern innovations that have been built upon it, one is taught to perceive that if a foot is collapsed in closed chain, it is pronated and that pronation exists in the Subtalar Joint (even more isolated, on its frontal plane).

    Using heel contact gait as the gauge fosters this perverse understanding of pronation.
    Forefoot contact gait obviates the importance of the STJ or its axis, or its importance as a joint in biomechanical diagnosis and treatment (possibly that is why "barefoot running", a disruptive biomechanical technology is considered so threatening to some biomechanists?)

    Functional Foot Typing, another disruptive biomechanical technology, by profiling all feet in order to determine the strengths and weaknesses of the rearfoot and/or forefoot inherent in each type as subgroups exposes the weaknesses of each section of the foot that can then be primarily treated in the area of weakness and not elsewhere with no prejudice.

    In fact:
    Rearfoot hyperpronation leads to a flexible, collapsed rearfoot structure.
    Rearfoot hypersupination leads to a rigid, well supported rearfoot structure.
    Forefoot hyperpronation leads to a rigid, well supported forefoot structure.
    Forefoot hypersupination leads to a flexible, collapsed forefoot.
    (See the two figures 1. pronated foot A and 2. pronated foot B)

    Labeling either of these feet "pronated" so as to describe it as collapsed or bad is IMHO, the Root of the stagnation in modern biomechanics that needs innovation.

    Functional Foot Typing and Foot Centering, define the rearfoot of A as flexible (collapsed) and the rearfoot of B as rigid and the forefoot of A as flexible (collapsed) and the forefoot of B as rigid (supported) which is much more easily understood and teachable. It allows its followers to focus treatment in the area of pathology and reduces the focus upon the rearfoot and The STJ as primarily dominant for either diagnosis or treatment.

    The reality is that in pronated foot A, the rearfoot is hyperpronated and in pronated foot B, the forefoot is hyperpronated.
    IMHO, most biomechanicst's brains would look at pronated foot B and never call it pronated on a test.

    Summarily, since the rearfoot has a positive incline and the forefoot has a negative incline inherent in its truss-tie beam structure, their respective joints have reciprocal pronatory and supinatory impact.
    Introducing to the novices and students of biomechanics the thought that pronation is bad and supination is good or that the rearfoot is the primary cause of biomechanical pathology needs replacing with a disruptive technology.

    On this basis, I suggest barefoot running and functional foot typing (Foot Centering) deserve examination and inspection.


    Attached Files:

  2. Griff

    Griff Moderator

  3. Yawn....yawn...
  4. 19/3/2012 :morning:
  5. blinda

    blinda MVP

  6. Haven't you learned anything, Blinda? If it doesn't have something to do with Foot CenteringTM blah blah blah, then you will be waiting a very, very long time for a response.
  7. blinda

    blinda MVP


    EDIT: Actually yes, I have just received a PM;


    Let`s keep this in the public domain, eh? I`m sorry if you feel affronted by the reminder of my unanswered questions but, no I still have no intention of debating your foot typing system with you.

  8. efuller

    efuller MVP

    Even if the question does have something to do with foot typing you will wait a long, long time.
  9. Sounds more like 1972 to me...
  10. David Smith

    David Smith Well-Known Member

  11. phil

    phil Active Member

    Hyperpronation and hypersupination are crappy words. Just like hypermobile 1st ray.

    Hyper-uppercut is a cool word though! Streetfighter is a cool game.

    Hope this is a valuble contribution to this thread.

  12. drsha

    drsha Banned

    That is why hyperpronation, hypersupination and hypermobile have been totally eliminated in Foot Centering language and replaced with new terminology.

    The first one we dropped was PRONATION which, to use your grammatical tone. is hypercrappy. That term is most confusing and wrenching when it comes to teaching and presenting biomechanics.

    You can add flat foot, compensated, partially compensated and fully compensated, forefoot varus and especially Forefoot VALGUS
    and STJ Neutral to the crap pile.

    How's that for destructive technology Phil?

  13. Agreed. very poor terminology. I'd not heard the term before you used it.

    This, however, is worse. The rigid actually means limited, not rigid. "Well supported" doesn't mean anything very much, and "rearfoot structure" is pretty meaningless. What is the "rearfoot structure" exactly? The calc? The sub talar complex? The sub talar, talo crural and CCJ?

    You Didn't drop the term pronation? Remind me what does PERM stand for again?

    Nothing wrong with "pronation". It has a globally agreed meaning (Pronation describes the motion of rotating towards the prone position) and a specific and globally agreed meaning in terms of specific joints (as in sub talar pronation being abduction, dorsiflexion and eversion). Where it goes a bit runny is where people use it in an inappropriate or unclear way such as a "pronated" foot or "over-pronation". Over what exactly? Pronated under which circumstances? Replacing these terms with others which are equally vague and non specific is not really helping, especially when one needs a key to translate the new technology into the existing.

    The correct way to describe a foot in which one can evert the rearfoot between, say, 10 degrees inverted to the leg and 3 degrees inverted to the leg is not supinated, hypersupinated, uncompensated rearfoot varus or even rigid rearfoot or rigid Serm. Its a foot in which one can evert the rearfoot between 10 degrees inverted relative to the leg and 3 degrees inverted relative to the leg. Look at it, say what it is. Anything else is not simplifying it, its complicating matters.
  14. drsha

    drsha Banned

    1.The reason that you have never heard hypersupination before is that pronation is the only movement considered pathological.
    In the forefoot (FHL) supination is the bad movement, so why haven't we ever heard of it before?

    2. When you deny architecture and take Newton as your king, these words will never have any meaning to you.
    Think for a moment about how torque, moment and tissue stress "translate" to the subtalar joint neutral Rootian students and practitioners.
    They seem to understand my terminology fairly well (when they actually visit it as so would you IMHO).

    3. I did as PERM = pronatory as in a motion not Pronated as in a position.
    Put away your microscope for a week (or even a day) Robert.

    I googled pronation. The first hit was a runners world article:
    Pronation, Explained
    Understanding your personal pronation type is crucial to choosing the proper running shoes. From the August 2004 issue of Runner's World
    If you have a normal arch, you're likely a normal pronator, meaning you'll do best in a stability shoe that offers moderate pronation control. Runners with flat feet normally overpronate, so they do well in a motion-control shoe that controls pronation. High-arched runners typically underpronate, so they do best in a neutral-cushioned shoe that encourages a more natural foot motion.
    This refers directly to a definition that pronation is rearfoot eversion and collapse and that too much must be stopped for healthy and perfomance issues.

    The second was Wikopedia, where it stated in addition to your definition:
    The pronated foot is one in which the heel bone angles inward and the arch tends to collapse. (A "knock-kneed" person has overly pronated feet.) It flattens the arch as the foot strikes the ground in order to absorb shock when the heel hits the ground, and to assist in balance during mid-stance. If habits develop, this action can lead to foot pain as well as knee pain, shin splints, achilles tendinitis, posterior tibial tendinitis, piriformis syndrome, and plantar fasciitis.
    Since the flexible rearfoot type is not the most common rearfoot FFT this means that the collapse and compensations referred to (and accepted) in this definition are in need of destruction.

    Your statement of "global agreement" in the definition of pronation is in Phil's words, crappy IMHO.

    5. No wonder why Simon says that we're all guessing and why you haven't come up with the evidence that you are trying to find. Your terms are too rigid (or is that limited?).

    In summary, The Arena is not global and your opinion of what is "The Correct Way" (until you have proof beyond expert opinion) is spam filtered from being validated and applied in my EBP and my work from day one when I became a member. and in four years of my involvment, nothing has changed (minimal, very low grade evidence and expert opinion).

  15. I didn't check that the definition of pronation fitted with the more authoritative sources, wikipedia and a running website?

    Damn. Is my face red. Ok, you've made your point. If wikipedia states that "The pronated foot is one in which the heel bone angles inward and the arch tends to collapse" then that pretty much wraps it up. Make me wonder why we bother with textbooks and university and all that. They obviously are not the authorative definitions. Could have just googled pronation and taken the first two descriptions.

    I'm going to go count to ten before I resort to saying whats on my mind. Maybe drink a little.

    Wikipedia. damn.
  16. efuller

    efuller MVP

    Interesting point here. There has been sort of a disconnect to how supination of the subtalar joint leads to a sprained ankle. I have to disagree, supination has been termed pathological. A foot that supinates too easily will get peroneal tendonitis. Tissue stress has been talking about these pathologies as be related to high supination moments from ground reaction force for years.

    Now this is a straw man argument. Mechanical analysis does not deny architecture or structure.

    Dennis, you may have a definition of the terms "rigid" "Well supported" and "rearfoot structure", but you won't find these terms defined the same way in podiatry schools. Changing the definition of words is more confusing. What makes you think that people understand your terminology? They don't ask questions?

    Dennis, I don't understand your comment about moment and tissue stress. When I taught these concepts, the vast majority of students were able to answer questions about these topics on the tests that they took. Besides, a year of physics is a prerequisite for entrance into podiatry school in the U.S.

    Now we can pick on your definition of global. In the global world of podiatry, we learn the definitions of joint motion and positions from anatomy textbooks. Since the definitions on wikipedia and runners world are different we need to make the decision on whose definition to take. I'd go with the anatomy textbooks. I'd also go with the person who names bones (calcaneus, talus) instead of uses terms like rearfoot structure, because the term rearfoot structure is not precise.

  17. As Eric has already stated, this is a straw-man fallacy. In addition, it is a disservice to Root and those who have studied and understood his writings. Root discusses torques, moments and tissue stress within his publications. Thus, these terms should need no translation to "the subtalar joint neutral Rootian students and practitioners". Remember too that many of us were directly, and indirectly, students and practitioners of Rootian biomechanics, yet we are more than capable of understanding these concepts; that you may not be able to Dennis, doesn't make it too complicated for the rest of us.
  18. I'll disagree with you there Simon. While I think they probably grasp the concepts you describe, I'm not sure they'll understand how "moment" translates. Maybe they'll understand it with hour. The concept may become more clear when they've read enough page.
    No its because its what I like to call "s**t you made up".

    Yeah, thats the problem, the terminology being used is to precise and unambiguous. We'd do better by using looser, more ambiguous terms which have different definitions depending on who is talking about them. Thats much better science.
    I'm not sure even you understand your terminology Dennis. Its so vague and amphorus as to be meaningless. What exactly IS a "well supported rearfoot"??

    So to be clear, when you SAY you "Dropped pronation" what you MEAN is that you "stopped using pronated to describe a position". But pronation as a motion you dropped. Forgive me for not realising that when you said pronation you meant pronated.
  19. Actually its been done


    "we wanted to cut through that high flown medical jargon"

    "Nurse, fetch me the electric paddles that can make you better if you're really sick but can make you sort of ill if you're fine!" Moments later: "Oh no... he was fine. And now he's poorly from too much electric.
  20. Bizzarre. That's exactly what I call it when Dennis writes his posts. Independently we have come up with a terminology to define these fallacious outbursts that I believe will be understandable to all.:drinks Over time, I've honestly come to the belief that he is making s**t up as he goes along.

    P.S. we can agree to disagree, Robert.
  21. drsha

    drsha Banned

    Yawn, I didn't suggest a stronger microscope, I suggested giving up the present one.

  22. drsha

    drsha Banned


  23. drsha

    drsha Banned

  24. drsha

    drsha Banned

    You're forgiven
  25. phil

    phil Active Member

    Um, yes, your technology is destructive. But not in the good way that you think it is.
  27. drsha

    drsha Banned

    No problem kind sir.

    That's what the horse and buggy makers said to Henry Ford and what the arch makers said to Merton Root, D.P.M.

    M. A. Rosanoff: "Mr. Edison, please tell me what laboratory rules you want me to observe."
    Edison: "There ain't no rules around here. We're trying to accomplish somep'n!"

    — Thomas Edison

    I wish you well.

  28. drsha

    drsha Banned

  29. drsha

    drsha Banned


    As an admitted bad graphics person with ni advanced software as of yet, I have reworked your chart to try and make foot typing sense here.

    I think the piece that you are overlooking is that almost all feet upon when a suoinatory motion is applied come to rest rigidly resisting additional movement from that moment in a positiion of inversion to leg in open chain. This repesents the relative contact position in closed chain in heel contact A to B Gait.

    From that position if you apply a pronatory moment, some feet will rigidly resist further eversion and end up in an inverted position to vertical, some will end up just vertical to the leg and yet others will end up in an everted position with respect to vertical (your call on how you define verticle.
    This position will come close to the position of the STJ on the frontal plane in early midstance in closed chain.

    Inverted SERM inverted PERM = limited in inversion to inverted,limited in eversion to inverted= Rigid Rearfoot FFT
    Inverted SERM Vertical PERM= limited in inversion to inverted, limited in eversion to vertical= Stable Rearfoot FFT
    Inverted SERM Everted SERM= limited in inverstion to inverted, limited in eversion to everted = Flexible Rearfoot FFT
    In addition (different and more clinically applicable as a classification system to Dr. Scherer's nine foot typing grid and the reason It got Patented), some feet resist vertical and are limited in an everted position when a SERM moment (forced inversion) is applied and they then are limited to an everted position when a PERM moment (forced eversion) is applied.
    Everted SERM Everted PERM = limited in inversion to everted, limited in eversion to everted= Flat Rearfoot FFT

    The chart shows the SERM-PERM excursions to your 5 classes and labels their FFT and I added another to show the Stable RF FFT as you did not have one of those.

    I hope you can envision how the STJ Axis, the CIA, the ones that will get PTTD become apparent as you see the total ROM differences and so many other foot type specific characteristics even this simple chart reveal.

    For example, you would never put a valgus wedge under the Rigid rearfoot Typers and you would never put a medial Kirby skive under a Flat RF type.

    I hope at least some of you can see that this starting platform is then tissue stress friendly.

    Also, the Grade 1 Rigid FFT woukd need more agressive treatment and present with more symptoms native to the Rigid RF Type than the Grade 2 Rigid FFT even tohugh both type Rigid RF. THis reduces the guesswork that Dr Spooner refers to.

    The Flat FFT of Grade 4 and the Flat FFT of Grade 5, depending on their Forefoot FFT would probably present with the same sympotoms and get the same treatment.
    Summarily, no cookie cutter here.

    Finally, in Grade 2 Rigid RF FFT, the STJ Neutral Position would be 1/3rd the way from the right to the left and that would be my positon when STJ Neutral castiing it.

    In Foot Centering, we apply a PERM moment to the cast everting the foot a number of degrees towards vertical therefore reducing the need for a Kirby lateral skive or Varus posting ORF's while holding the foot in a more Optimal Functional Position than STJ Neutral.

    The resulting Shell places the foot in a more centered position. Voila!

    Henry Ford (LOL)

    See Attached Chart;
    legend: the green arrow represents a Stable RF FFT

    Attached Files:

  30. Just the one?

    Whats a perm moment?
  31. The irrelevant humour fallacy. You'd do well to remember that a joke might win an audience, but it does not win an argument.

    When Ian first wrote "yawn" it carried with it some humour. Your repeated use of it when you cannot counter the argument put to you makes you look callow and incapable of original thought.
  32. They probably said that to Timothy Zell before he entered patent 4429685. But he went ahead and did it anyway!

    Went well.

    Mr Blonsky probably faced similar opposition from the entrenched medical community over his disruptive technology in patent US3216423.
  33. Thank you Dennis you have just succeeded in proving my point from the other thread. The specific posts are here:

    The position and thus the classification achieved is dependent in part upon the loading applied- it's the amount of pronatory force applied. You are assuming each of the 5 clinicians are applying the same force. In my example, they were not and reality they won't either. Thus, our 5 clinicans may classify the same persons foot with different "types" due to variation in the load they apply during their manual examinations and embark on different orthotic prescription protocols as you have now shown. :drinks

    P.S. I'm sure it would help others attempting to read and follow a thread if you kept the relevant discussion within the relevant thread, rather than mixing them across as you have done here.

  34. drsha

    drsha Banned

    About a minute and a half.:cool:


    It's the time you save when you go to the beauty parlor and push the stylist to rush their treatment.:cool:

    Seriously, why in the world would you want to know an answer to this question if my work and me personally are so banal.

    Give me some positive reasons why you want this question answered or own up to some of the same flaws in your bioNewtonian world that you accuse me of failing at.


    Most of all, stop being the judge and jury on anyone else's effort other then your own.

    If not, let's call my lack of response to your query "The Fuller Effect" that I now offer to you as my reply.:pigs:

    or wait for the upcoming Root-Tissue Stress into Foot Centering Dictionary that will be on your bookshelves soon.
    disclaimer: profit motive here:cool:

    "You must give to get, You must sow the seed, before you can reap the harvest". -- Scott Reed

    "What isn't tried . . . won't work". -- Claude McDonald

  35. drsha

    drsha Banned


  36. drsha

    drsha Banned

    I so totally disagree.

    No matter how fast a train pulls up into the station or a boat to a dock, it rigidly resists the station or dock or the station or dock rigidly resists moving (short of destruction).

    A 10 mile an hour wind, a 30 mile an hour wind and a 50 mile an hour wind all stop at your homes front door resistance until a 100 mile an hour wind comes and blows it away.

    Each foot rigidly resists the confines of the ankle mortise and its axis differential and it starts and stops at a given place (unless it dislocates) differently than other feet.

    Additional motion is provided by soft tissues or some other part of the system (such as plantar heel pad, ankle or midtarsal joint pronation).

    You cannot take a class 1 rigid rearfoot type and make it reported as a class three flexible type by adding more PERM moment, Period.

    Your example may be theoretically possible but not realistic, I;m sorry to say.

    "I think perfect objectivity is an unrealistic goal; fairness, however, fairness is not".
    Michael Pollan

  37. Dennis we only need enough variation in force to change the angle of the rearfoot by one degree for it to go from inverted to vertical and by a further degree to become everted. Since if the "PERM" is 1 degree inverted its a "rigid rearfoot type", if its vertical its a "stable rearfoot type" and if its 1 degree everted its "flexible rearfoot type". I'd say it is highly likely that there should be more than one or two degrees variation between clinicians in performing this task due to (amongst other things) the force they apply during their manual examinations. And given that your orthotic design is different for a "rigid rearfoot type" and a "stable rearfoot type" and different again for a "flexible rearfoot type" then a variation of only two degrees between three clinicians could result in the same patient being prescribed three different types of orthosis for their singular foot.

    Your rigid categorical approach also calls for the clinician to accurately differentiate one degree differences in rearfoot position, presumably by eye. Even for an experienced clinician I'd wager that this is impossible.

    As I said several years ago, the problem isn't when the foot being "typed" is very inverted or very everted, it's when its in that grey area in the middle- that's the problem with applying qualitative categorical labels to a variable which is in essence quantitative in nature. Do three different feet: one with a "PERM" of 1 degree inverted, one with a vertical "PERM" and one with a "PERM" which is one degree everted each really function in a completely discreet and different manner? Enough to warrant completely different orthotic designs? It seems to me that this is what you are advocating.
  38. If I find the time I'll try and set this up: I'll get a foot and photograph it in three different rearfoot positions: 1 degree inverted; vertical; 1 degree everted. I'll post the pictures up and set up a poll and people can vote on which one they think is which.

    If someone else has the inclination, go ahead.
  39. Can you define "a more centered position"? Is this with the "PERM" vertical?

    BTW, your analogies here are poorly chosen and demonstrate your lack of understanding of mechanics and thus of biomechanics too.

    If the train and boat hit the station or dock with different velocities the impact forces will be different too. This will result in different stresses and strains within the train and station; boat and dock. The station and train, the boat and the dock, all deform during the collisions.

    That no visible change in position is observed with the naked eye when the wind blows on the door does not mean that the forces applied to the door and thus, the stresses and strains within the door and its frame are the same regardless of how fast the wind blows against the door. They are not. The door deforms under loading just like the train, station, boat and dock ("moves" if that makes it easier for you to understand); the amount of deformation that occurs to the door will be dependent on wind speed. We call this "physics".

    Look at the image attached, understand it and it's implications to what you are saying. If you don't understand you can always ask for help, Dennis.

    Attached Files:

  40. drsha

    drsha Banned

    I remember your overlapping bell curves so no need for a diagram as I understand this question fully, it is a common Q & A as folks are learning to foot type and apply the exam to a prescription.

    The hest way that I can explain this is to state that as you so well state, clinicians are not that sophisticated to differentiate a variable number of degrees as close as 1 degree any more than he/she can determine small degrees of temperature with accuracy.

    87 degrees feels the same to us as 90 degrees yet we call both feet equal in temperature or claim there to be assymetry in temperature. We note a six degree difference as warm to the touch.

    So for me, unless there are other factors extrinsic to the RF SERM-PERM, the 1 degree inverted, the vertical and the 1 degree everted all get a zero degree (flat) RF post as to frontal plane treatment.

    To use your expression, the guess work still exists interpersonal but is reduced with a foot typing. Also, as we monitor the Centrings over time, we are looking for muscle engine training and reactive changes proximal and distal to the RF and alter the post position accordingly as with most other systems but this rarely occur.

    You and I agree that there are practical variables in all systems yet you continue to state that my system is rigid and cookbook which is due to your lack of experience with it.

    In response how do you judge the need for a 5 degree medial heel skive as opposed to a 4 or six as your measurements and tools are so inaccurate?

    "Practice what you preach"--

    Here's 4 balls, here's how to juggle, now the analogy is that before you have tried to juggle, practiced it or been mentored, you say juggling can't work. and you'll never be in the circus.

    Summarily, FFTing is fallable just like your system or any other.
    The art ans science of medicine.

    You're the one turning this into physics not me.


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