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Do We Overcomplicate or Oversimplify Biomechanics.

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Robertisaacs, Jun 9, 2009.

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    I stumbled across a quote yesterday which crystallised something which had been lurking in the back of my brain for a while.

    "Make everything as simple as possible, but not simpler."
    Albert Einstein

    There have been many threads recently which touched on this. The COP / COF is one, technically different but used interchangeably. There was a clinical question on knee pain where the question and biometric information which went with it was, perhaps, a little TOO simple to be useful. There is the nav drift - drop / planal dominance question. Not the same, but can they be used as such?

    I know many very experienced and capable clinicians who have been practicing for decades who would not know what a vector or axis was. Show them a force equation and they'd not know where to start. Yet they understand how the foot works in a way only 20 or 30 years of experience can achieve.

    I have also known clinicians make the most horrible mistakes because they don't understand the basics of how the foot works; and who over rely on their experience.

    I have previously observed that there may be a difference in what one needs to be an effective clinician vs. what one needs to be at the leading edge of theoretical thought (as the leaders of this forum are). Put allegorically, does one need to be a mechanic to be a driver? Is it enough to know WHAT something does without understanding WHY? Is there a happy medium and if so where is it?

    So here are the questions

    1. Is there a level of simplification which is appropriate for pure clinicians?

    2. Should those seeking to be effective as clinicians (but not to advance the understanding of the profession) accept a lower level of understanding as adequate or should they constant seek the total understanding?

    3. Should those who lead the understanding of the profession strive to bring everyone up to the highest level or should they seek to make it more accessible.

    What say you? What is "as simple as possible?"

  2. I strive toward the opposite end of the spectrum: "as complicated as you can understand".

    edit: complicated is not the right word,

    "as accurate as you can understand" is better. However, accuracy and complexity often go hand in hand.
    Last edited: Jun 9, 2009
  3. Last edited: Jun 9, 2009
  4. Graham

    Graham RIP


    Agreed. So how do we impart the complexity of the theories with their clinical application?
  5. I think the answer is yes to over complicate, maybe a better a question would be is this a bad thing.

    Ive spent the last few days getting (or trying to) my head around what you and Simon were discussing with Navicular drift/drop.

    Ive then looked at the papers by Arnt, Nester et al, with their bone marking which show that the amount of movement in body planes of the joints of the foot is very small generally. So how are we expected to see 5 degree movements using the eye with all the soft tissue and skin... we can not.

    But if the clinical Podiatrist is not challenged by Patient feedback, research, other pods then we will not get greater understanding of the foot and lower limb mechanics.

    so I thank you for challenging my understanding with your discussion. But until we can have a computer model/scan of each patients foot during gait that can mark the exact points of axis, direction and amount of movements etc we are just guessing. Some more educated than others.

    They say knowledge is power, but to die with knowledge that has not be passed on is a waste of time.

    I look forward to reading more complex discussions and hopefully adding to them

    Michael Weber
  6. Personally, I think Prof. Kirby has done an outstanding job in this regard. Having had the pleasure of writing a review of his third book of collected newsletters recently, I had good reason to critically examine both the content and writing style employed by him. Kevin has the ability to put across complex principles using everyday examples. The language he uses is plain but precise. The reader is not bogged down with complex mathematics. He builds from the simple to the complex and then goes on to provide useable clinical applications. I suspect that it's partly his up-bringing, partly his obsession with accurate terminology, illustration, grammar and punctuation and partly Pam's influence on him.;) But I don't care what planet you're from, this guy is an excellent teacher of podiatric biomechanics.

    But that's more than enough gas up his ass. :pigs:
  7. I'm there too :drinks Sadly thats a very different point for all of us! But I'm in the happy position that biomechanics is my hobby as well as my job. I guess thats true for many here. Just check the times on the posts ;). For most its as complex as they WANT to understand.

    Not my word. Take it up with Einstein. ;)

    Seriously though, the difference between the words can be taken from their opposites. Opposite of complexity is a scale and simple and complex can both be appropriate. Opposite of accurate is inaccurate and thats seldom a good thing.

    Yeah yeah i'm going back there now!

  8. davidh

    davidh Podiatry Arena Veteran

    Good for you!

    It's subjective - and I know you'll forgive me for not joining in and making it all complicated!

  9. Agreed. :drinks Yet as excellant as Kevin, Eric (whose posts I always find most incisive) Dave and of course your good self are at imparting accurate information there are many who will find them passing several yards above their heads. Only they won't be on here to agree cos they lurk, open mouthed and baffled before their screens, terrified to post lest they be flamed for their lack of understanding.

    I've seen em. They're nocturnal, shy and hard to find without infra red camera's, time lapse photography and David Attenbourgh, much like otters. But I suspect they exist in large numbers.

    Kind regards
  10. Agreed.
  11. blinda

    blinda MVP

    :eek: Dammit, I keep forgetting to turn off the webcam....
  12. Griff

    Griff Moderator

    Like Robert, I couldn't agree more. Kevin's books have steered me through many a potential brain implosion post clinic. I just love his writing style. From the looks of another recent thread I don't think 'Mr Nake' will echo our sentiments...
    Last edited: Jun 9, 2009
  13. And yet, there are others who ask questions which appear straight forward on the surface such as this one:


    The replies thus far say things like hallux limitus, but I challenge you to analyse the question. Why do we "build up" callus? Now there is a complex question that could require a very complex answer. Will Carol be happy with "hallux limitus" response, or did she want us to start talking about the histo-pathology of callus formation?

    There are no stupid questions......

    Let's see how this discussion develops.

    It's very simple. If you don't understand something, you can always ask for it to be explained for you in terms you do understand. The biggest barriers here are pride and the ego.
    Last edited: Jun 9, 2009
  14. See what I mean:
    Now how many of you when you read Carol's original post were thinking: "os sesamoidum interphalangeum"

    Luckilly, Lucky Lisfranc was ;) Yeah, it was on the tip of my tongue- not. I just got educated.
  15. Robert:

    This could be the best thread of discussion so far this year! Good job, Robert!

    When I lecture at seminars, the diversity of background of my audience is still my most challenging problem. I make every attempt at trying to make it interesting for the most intelligent and advanced of my audience while still trying to make most of the lecture understandable for the least experienced or least educated of the audience. For those of you who have lectured to large audiences as I, and many others on Podiatry Arena have on many occasions, it is an impossible task to make biomechanics easy for everyone since some people just don't have the capacity to learn this material quickly and easily as others do.

    For example, I try to read all the reviews from my lectures when they are made available to me. These reviews may range from comments such as, "Kirby uses too much engineering and physics terminology and I don't see why he can't simplify things more for the average podiatrist", to comments such as, "Kirby should be presenting much more advanced material since he spends too much time explaining basic mechanics and physics concepts".

    In my private discussions with Dr. John Weed when I was a podiatry student, Dr Weed would often say (to paraphrase him) that in his years of teaching biomechanics he had found the following: 1/3rd of his students loved him, 1/3rd of his students hated him and the remaining 1/3rd of his students were still trying to figure out if they loved him or hated him. I was in the 1/3rd of the class that loved the man.

    In my quarter century of teaching biomechanics to podiatrists and podiatry students, the bottom line is that unless the student/podiatrist has a better than average ability to visualize things in their mind three-dimensionally, has better than average math skills, has had some basic physics courses and, most importantly, has the desire to learn biomechanics, then these students/podiatrists will not master the subject regardless of who is teaching it. We must not always assume that it is the teachers fault when a subject is not understood well by a student or clinician. I believe the students are just as much to blame for their lack of understanding for either their lack of aptitude for the subject or their lack of interest in learning the subject. Sometimes, there is simply not enough time available to teach a student one on one, hand feeding them the information, so that they understand the concepts completely. This is the nature of medical education, and of life in general, where the most fit, most motivated and ones that are willing to make the extra effort to understand a subject will perform the best and the least fit, least motivated and ones that are unwilling to make the extra effort to understand a subject will perform the worst.

    Great discussion.
    Last edited: Jun 10, 2009
  16. Craig Payne

    Craig Payne Moderator

    Robert - depends what you mean by simplified?

    There are the reductionist approaches that really 'dumb' it down to what I call a 'cookbook' approach. Ie a basic foot assessment --> 'pigeon hole' the patient --> follow the recipe to prescribe orthotics (problems happen when the patient does not have a pigeon hole to fit in; also a problem with the limited number of clinical test/observations needed to pigeon hole them.)

    Then there are the systematic approaches (which still can be 'simplified') in which you do not 'pigeon hole' or 'foot type' and you systematically work through a whole range of clinical tests/observations/etc and each one of those determines the prescription or not of a particular variable in the negative model production and orthotic manufacture (or prefab modifications).

    I see both approaches as being "simplified" and not complicated (and prefer the systematic approach over reductionist approaches).

    What is complicated may be the understanding of the evidence and theoretical basis for the clinical tests in the systematic approaches (I see little evidence for the 'cook book' approaches).

    Maybe you asking something like a physician need to know the steps to go through to work out which drug prescription to give or not give; needs to know the mode of action; but does not need to know the biochemistry of the drug ...
  17. AtomAnt

    AtomAnt Active Member

    Is that not making it more complicated? Does it really matter to us if an approach is reductionist or systematic? We just want to prescribe orthotics that make patients better.

    Having said that, I do appreciate your efforts at trying to sort it all out. I was at the Boot Camp in Adelaide at the weekend when this came up.
  18. Craig Payne

    Craig Payne Moderator

    I will have to give Ted credit for questioning me on this one when I used the term 'cookbook' ... questions always force me to more clearly think things through. Reductionist is probably a better term to use than "cookbook" for the sorts of prescription protocols and theoires I lump in that category.
  19. Craig Payne

    Craig Payne Moderator

    From Wikipedia:


    René Descartes, in De homine (1662), claimed that non-human animals could be explained reductively as automata; meaning essentially as more mechanically complex versions of this Digesting Duck

    Reductionism is any of several related philosophical ideas regarding the associations between phenomena which can be described in terms of other simpler or more fundamental phenomena.[1]

    The Oxford Companion to Philosophy suggests that reductionism is "one of the most used and abused terms in the philosophical lexicon" and suggests a three part division:[2]

    1. Ontological reductionism: a belief that the whole of reality consists of a minimal number of parts.
    2. Methodological reductionism: the scientific attempt to provide explanation in terms of ever smaller entities.
    3. Theory reductionism: the suggestion that a newer theory does not replace or absorb an older one, but reduces it to more basic terms. Theory reduction itself is divisible into three parts: translation, derivation and explanation.[3]

    Reductionism can be applied to any phenomenon, including objects, explanations, theories, and meanings.[3][4][5]

    For the sciences, application of methodological reductionism attempts explanation of entire systems in terms of their individual, constituent parts and their interactions. For example, the temperature of a gas is reduced to nothing beyond the average kinetic energy of its molecules in motion. Thomas Nagel speaks of 'psychophysical reductionism' (the attempted reduction of psychological phenomena to physics and chemistry), as do others and 'physico-chemical reductionism' (the attempted reduction of biology to physics and chemistry), again as do others.[6] In a very simplified and sometimes contested form, such reductionism is said to imply that a system is nothing but the sum of its parts.[4][7] However, a more nuanced opinion is that a system is composed entirely of its parts, but the system will have features that none of the parts have.[8] "The point of mechanistic explanations is usually showing how the higher level features arise from the parts."[7]

    Other definitions are used by other authors. For example, what John Polkinghorne terms 'conceptual' or 'epistemological' reductionism[4] is the definition provided by Simon Blackburn[9] and by Jaegwon Kim:[10] that form of reductionism concerning a program of replacing the facts or entities entering statements claimed to be true in one type of discourse with other facts or entities from another type, thereby providing a relationship between them. Such an association is provided where the same idea can be expressed by "levels" of explanation, with higher levels reducible if need be to lower levels. This use of levels of understanding in part expresses our human limitations in remembering detail. However, "most philosophers would insist that our role in conceptualizing reality [our need for an hierarchy of "levels" of understanding] does not change the fact that different levels of organization in reality do have different 'properties'."[8]

    Reductionism strongly represents a certain perspective of causality. In a reductionist framework, the phenomena that can be explained completely in terms of relations between other more fundamental phenomena, are termed epiphenomena. Often there is an implication that the epiphenomenon exerts no causal agency on the fundamental phenomena that explain it. The epiphenomena are sometimes said to be "nothing but" the outcome of the workings of the fundamental phenomena, although the epiphenomena might be more clearly and efficiently described in very different terms. There is a tendency to avoid considering an epiphenomenon as being important in its own right. This attitude may extend to cases where the fundamentals are not obviously able to explain the epiphenomena, but are expected to by the speaker. In this way, for example, morality can be deemed to be "nothing but" evolutionary adaptation, and consciousness can be considered "nothing but" the outcome of neurobiological processes.

    Reductionism should be distinguished from eliminationism: reductionists do not deny the existence of phenomena, but explain them in terms of another reality; eliminationists deny the existence of the phenomena themselves. For example, eliminationists deny the existence of life by their explanation in terms of physical and chemical processes.

    Reductionism also does not preclude the existence of what might be termed emergent phenomena, but it does imply the ability to understand those phenomena completely in terms of the processes from which they are composed. This reductionist understanding is very different from emergentism, which intends that what emerges in "emergence" is more than the sum of the processes from which it emerges.[11]

    1. ^ Cite error: The named reference MerriamWebster was invoked but never defined (see the help page).
    2. ^ Michael Ruse (2005). "Entry for "reductionism"". In Ted Honderich (ed.). The Oxford Companion to Philosophy (2nd ed.). Oxford University Press. p. 793. ISBN 9780191037474.
    3. ^ a b Cite error: The named reference Ney was invoked but never defined (see the help page).
    4. ^ a b c John Polkinghorne (2002). "Reductionism". Interdisciplinary Encyclopedia of Religion and Science. Advanced School for Interdisciplinary Research; Pontifical University of the Holy Cross.
    5. ^ For reductionism referred to explanations, theories, and meanings, see Willard Van Orman Quine's Two Dogmas of Empiricism. Quine objected to the positivistic, reductionist "belief that each meaningful statement is equivalent to some logical construct upon terms which refer to immediate experience" as an intractable problem.
    6. ^ Cite error: The named reference Nagel was invoked but never defined (see the help page).
    7. ^ a b Cite error: The named reference GodfreySmith was invoked but never defined (see the help page).
    8. ^ a b Cite error: The named reference Jones was invoked but never defined (see the help page).
    9. ^ Simon Blackburn. "Entry on 'reductionism'". Oxford Dictionary of Philosophy. p. 311.. Richard Jones distinguishes the two, arguing that many ontological and epistemological reductionists affirm the need for different concepts for different degrees of complexity while affirming a reduction of theories. Richard H. Jones (2000), Reductionism: Analysis and the Fuullness of Reality, pp. 27-28, 32. Lewisburg, Pa.: Bucknell University Press
    10. ^ Jaegwon Kim (2005). "Entry for 'mental reductionism'". In Ted Honderich (ed.). The Oxford Companion to Philosophy (2nd ed.). Oxford University Press. p. 794. ISBN 9780191037474.
    11. ^ Axelrod and Cohen "Harnessing Complexity"
  20. Craig Payne

    Craig Payne Moderator

    From the Merriam-Webster online dictionary:

    1: relating to or consisting of a system
    2: presented or formulated as a coherent body of ideas or principles <systematic thought>
    3 a: methodical in procedure or plan <a systematic approach> <a systematic scholar> b: marked by thoroughness and regularity <systematic efforts>
    4: of, relating to, or concerned with classification ; specifically
  21. AtomAnt

    AtomAnt Active Member

    Maybe an example here would be the story Craig told at the Boot Camp about the ankle joint range being 10 degrees. Life was good and simple when it was 10 degrees. Now we know its not, life has got much more complicated, because the answer is not going to be a specific range of motion. The answer is going to be different for each person.

    We want simple, but to be a good clinician, getting it right for the ankle joint range of motion is not going to be simple.
  22. David Smith

    David Smith Well-Known Member

    Hi all

    Just came to this thread today and its a good one.

    Robert asked
    The problem with human knowledge is that it has no limitations, no boundaries, no permanent fixed points of reference. The complete data that describes a certain simple phenomenon can be so huge as to be almost infinite. Hence the 'expert' can spend a lifetime learning more and more about less and less.

    At Strathclyde University their Logo was 'Centre of Useful learning' and 'useful' is the focus of all study. We need to evaluate if, the data we collect through study (i.e. process of learning) is useful for the problem we will apply it too.

    As an example the data collected by, let's say a force plate, can be extremely complicated but ultimately does describe precisely the action of interest. This data is only from one point of view however, e.g. based on the measurement of the differential of an electrical charge.

    To get useful data from this complete set we need to get rid of a lot of it and change the nature of what's left so as it can be usefully displayed as an output that a human can understand. It's not all the data and it's not necessarily a true or precise representation of the collected data and it is only one version or point of view but it does characterise the action of interest in a very useful way for our purposes at that time.

    This is the great benefit of education I.E. obtaining the ability to filter out the data we do not require to solve the problem at hand. This skill takes years to be good at and never can be completely mastered. The expert again, filters out, finds or defines useful knowledge for his field of interest that reflects his point of view.

    So the clinician can say to his or her self "do I need to have this knowledge or data to be useful in my profession"?. "How much more useful will I become by obtaining more data about my subject of interest"?. Some will be satisfied with what they have and others will strive to filter data till the ends of their careers or even lives.

    Now where you lay along that scale and how you feel about your position and rank within and along that scale is a matter for each individual to put to themselves.

    Are the data you possess useful for your professional life and are you satisfied with where you are?

    Cheers Dave
    Last edited: Jun 13, 2009
  23. Lawrence Bevan

    Lawrence Bevan Active Member

    The steps after realising the above

    1 we realise that things can be so complex and multifactorial that it is impossible to process them all

    2 next we remember that our measurements are inaccurate and can be no more precise than +/- 5 degrees

    3 Having done that we formulate a simple working practice of "ankle dorsiflexion greater than 10 degrees"

    4 Next generation of Podiatrists question why there is an arbitrary rule of "ankle dorsiflexion greater than 10 degrees" when surely things are much more complex and multifactorial

    5 repeat steps 1-3
  24. Dennis Kiper

    Dennis Kiper Well-Known Member

    "as accurate as you can understand" is better. However, accuracy and complexity often go hand in hand.

    When accuracy is supported by science and confirmed by technology, complexity becomes much easier
  25. Rob Kidd

    Rob Kidd Well-Known Member

    A quote from R J Mitchell (designer of the spitfire) to his test pilots is worth remembering. "If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: it's all balls".
  26. davidh

    davidh Podiatry Arena Veteran

    Mitchell was onto something. So was Einstein.
    Podiatric Biomechanics can never be fully understood, and will always be complicated, as long as we persist in using the gait lab floor as a reference point for everything which goes on above the sole of the foot.

    An old thread, to which I'm delighted to make another brief contribution.
  27. Dennis Kiper

    Dennis Kiper Well-Known Member

    Podiatric Biomechanics can never be fully understood, and will always be complicated, as long as we persist in using the gait lab floor as a reference point for everything which goes on above the sole of the foot.

    You might not be aware of the technology of the “gait lab floor” it can accurately give data relative to
    loading time
    proportionate peak pressure and force amplification
    distribution and balance of GRF of the medial and lateral columns
    and timely consequence of foot contact to the ground

    this of course is relative to having accurate, reliable and consistant data. Once you can achieve this, then biomechanical function can be more accurately interpreted.
  28. efuller

    efuller MVP

    I actually believe that foot biomechancis could be fully understood. There are a limited number of bones ligaments and tendons. Newton's laws tells us what cause motion(s). Using finite element analysis we can figure a lot out from there. Understanding is mostly just asking the right questions. You are going to have a hard time understanding biomechaincs if you focus on just positions of joints (neutral position).

    On the other hand, we are dealing with people who sometimes present with conflicting symptoms and it is difficult to accurately determine what the "biomechanical" problem is. We often have to guess which anatomical structure that is injured.
  29. davidh

    davidh Podiatry Arena Veteran

    Well yes, but only in relation to a gait lab floor.
  30. Dennis Kiper

    Dennis Kiper Well-Known Member

    A gait lab floor is as level as the ground we walk on. That's what most people walk on.
  31. Dennis Kiper

    Dennis Kiper Well-Known Member


    Understanding is mostly just asking the right questions.

    I don't think “questions” will lead you to understand biomechanics. Because you have to address mechanical efficiency to the mechanics of biomechanics. It's a structural dynamic mechanical issue that determines lever arm efficiency—tissue efficiency (tissue stress) is secondary to that.

    Fitting an orthotic (providing the pt's criteria fits the technology) to the foot should not be based on symptoms. (It's like fitting glasses for vision). It's more of a correction (or better, a modification) of the planes of motion, modifying the efficiency of stance phase. When one understands the mechanics of arch motion, then you can more accurately interpret function. I find that this leads to more accurate predictability of outcome.
  32. davidh

    davidh Podiatry Arena Veteran

    Hi Denis,
    The flat, hard surfaces encountered in a gait lab are found in:
    a) The Pope's Palace.
    b) Shopping Malls.
    c) Nowhere else.

    Ok - I'm being flippant, but you must agree that pavements and other terrain are not uniformly flat. A crack in the asphalt, tip in a paving stone, or the odd soft bit of grass - each represents a degree or two ( one of our chosen units of measurement).
    I think too, that all sorts of force and kinematic data is produced without any regard to Circadian or Diurnal variation, which invalidates much of that data, unless specifically mentioned beforehand and + built-into data collection. One cannot simply ignore recognised biological phenomena because its existence is inconvenient.

    My point really though, is that the modern human foot is probably capable, at the Ankle Joint Complex, of much more movement than has previously been described. It seems to me that we've gradually accepted horizontal, unyielding surfaces as our normal habitat, and this has, over time, become convention.

    To me, podiatric biomechanics makes much more sense if we acknowledge that our feet are designed for support and ambulation on a mix of terrains - horizontal and unforgiving being one of them. If we relegate (with no science to back it up) the foot as a structure which has developed for life on the hard and horizontal we begin to complicate things.
  33. Dennis Kiper

    Dennis Kiper Well-Known Member

    Flippancy aside, concern for the ROM of the ankle complex is important when you're climbing rocks and trees. I think we can all acknowledge that “ our feet are designed for support and ambulation on a mix of terrains”. If you re-read my last post, I'm talking about the intrinsic mechanicsof the primary and majority of our walking surfaces. If you are talking about odd planes then we'll never get anyplace,

    What I don't understand is “If we relegate (with no science to back it up) the foot as a structure which has developed for life on the hard and horizontal we begin to complicate things.

    What are you saying? You seem to be theorizing the ability of the ankle complex. I'm talking about collecting reliable, consistent and accurate data of the mechanical operation of stance phase. When you make an orthotic to assist the foot through that operation, you can more easily understand the intrinsic function. GRF is the essence of that intrinsic operation (based on balance). That data is followed up by loading time and foot contact to the ground.

    Biomechanics as you understand it has no science to support it, -every gait analysis performed with traditional orthotic technology is invalidated because it is inconsistent, unreliable and inaccurate (that's what makes it complicated)
  34. David Smith

    David Smith Well-Known Member

    Much as I hate to agree with Mr Kiper, I think he has a point - Biomechanics is about gathering reliable repeatable and robust data and so we need a clear orthoganal reference frame, if we don't have one then it becomes very difficult to apply that data to an everchanging model with an everchanging refrence frame.
    On the other hand, that's the problem David is talking about, in real life it is rare to perform on perfectly orthoganal surfaces, although the sports arena and fields come close, and rare to have consistent kinematic and spatio-temporal performance that directly affects the kinetics that we rely on to manipulate in order to reduce injury or improve efficiency.
    What's the answer? I think one answer is to take what we have learned thru experimentation in the lab environment and then use suitable instrumentation, such as IMU's, to gather data inthe real world environment and do a meld - make inferences and assumptions based on what we know and applied to what we observe, where both have objective data that are useful to keep our assumptions real.
  35. Dennis Kiper

    Dennis Kiper Well-Known Member

    David S.

    in real life it is rare to perform on perfectly orthoganal surfaces, although the sports arena and fields come close, and rare to have consistent kinematic and spatio-temporal performance that directly affects the kinetics that we rely on to manipulate in order to reduce injury or improve efficiency.

    What's the answer? I think one answer is to take what we have learned thru experimentation in the lab environment and then use suitable instrumentation, such as IMU's, to gather data inthe real world environment and do a meld - make inferences and assumptions based on what we know and applied to what we observe, where both have objective data that are useful to keep our assumptions real.

    David S,
    rare to have consistent kinematic and spatio-temporal performance that directly affects the kinetics that we rely on to manipulate in order to reduce injury or improve efficiency.

    Herein lies much of the problem. Your approach is to “manipulate” rather than “assist” the normal motion of the individuals pronatory and wt bearing forces and modify its ROM. My approach is to minimize/modify those same forces by limiting the ROM throughout stance phase and provide stability to the structure in all 3 planes of motion (planes of the surface aside). Your reliance on kinematics using a non-science supported technology will always leave you looking for mor answers.

    The issue again is mechanical efficiency of the mechanics of the biomechanical being. It becomes hit or miss in your approach to heal tissue injury. If the individuals biomechanics adapts to the functional orthoses, then you can have success, but only for a limited time. Eventually the Rx or biomech motion changes-(as a result of reduction of tissue stress AKA tissue inflammation/tissue inefficiency)--wouldn't a better approach be to use a quantitative Rx (that adapts to the foot mechanics) that allows you to measure the change in biomech motion rather than try and manipulate the Rx? Units of +/- 5 degrees of the planes of motion at the tarsus is enormous in a science based technology for the same purpose.

    To take it a step further, if you simply occupy the space under the tri-complex axis of the planes of motion so that the foot works at it's biomechanical functional greatest mechanical and tissue efficiency, I call that the optimal position traditionally known as neutral.

    Changing the angles of the complex by increasing or decreasing those angles takes mg. To change it up to 5 degrees would be a major structural shift and secondary effect on lever arm efficiency
    Last edited: Jun 12, 2018
  36. Dennis Kiper

    Dennis Kiper Well-Known Member

    What kind of engineering and physics are you teaching that the avg pod doesn't understand? I don't remember when I learned my engineering (more on the job), but I learned the physics of my technology in high school, just like everyone else--his name was Archimedes
    Last edited: Jun 13, 2018
  37. Dennis Kiper

    Dennis Kiper Well-Known Member

    His name was Archimedes
  38. David Smith

    David Smith Well-Known Member

    Archimedes!? Have you thought about updating to Newton Dennis?
  39. Griff

    Griff Moderator

    In the last few weeks I have seen a handball player, a basketball player, an indoor volleyball player, a track athlete, a floorball player and a futsal player (to name but a few).

    All ply their trade on very hard, very flat surfaces. Just sayin.
  40. davidh

    davidh Podiatry Arena Veteran

    Dr Kiper, thanks for coming back.
    This ^ is the crux of the matter.

    In Practice I used a Tekscan for a long time, before that a Musgrave system. Before that a video and treadmill. In 1995 Durham University sent me up to Edinburgh to look at one of only two or three Vicon systems in the UK at that time in action. Each system is useful but has limits. The very sophisticated Vicon (5-camera system and forceplate, costing at that time near to £500,000) in particular was disappointing, and that was before I read about Circadian and Diurnal variation and did some experimentation myself. Each system gives pretty accurate data of how that patient performed at that moment in time on a treadmill/forceplate/vertical loading system.

    At a different time of day, on a different supporting surface, the data will be different. That being the case, one has to ask if video alone is as useful clinically? The manufacturers of expensive gait systems would say not, I believe.

    The sports field of course has a slightly different surface to the gait lab, in that is has some "give".

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