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What Is The Science Behind Biomechanics?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by drsha, Sep 3, 2011.

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  1. drsha

    drsha Banned

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    To The Arena Guru's et al:

    "In general we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong.

    In that simple statement is the key to science.

    It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is — if it disagrees with experiment it is wrong. That is all there is to it." --

    Richard Feynman

    From the existing evidence and with an open mind,
    My Guess Is As Good As Yours?

  2. efuller

    efuller MVP

    Dennis, nice quote. It helps illustrate the difference between functional foot typing and tissue stress biomechanics. With tissue stress biomechanics you can devise and experiment to see if it works. I don't see how you devise an experiment with foot typing. So, you name the type of the foot, then what. That's not devising or determining, a treatment for the foot. Now, if you based your orthotic design on the type of the foot, then you might be able to get to the experimentation stage. For example, in tissue stress biomechanics you would predict that posterior tibial dysfunction would get better with a varus wedge orthotic and worse with valgus heel wedge orthotic. This is the testing and experimentation that Fennyman refers to. In fact, the successful results of the use of a valgus wedge for medial knee compartment arthritis has literature to support the theory. A valgus wedge has been shown to reduce symptoms. A valgus wedge is predicted to reduce knee abduction moments and the theory predicts that it does reduce knee abduction moments.

    So, Dennis, how would you devise an experiment to test functional foot typing? What are the predictions of foot typing? How do you alter treatment based on foot types? So I don't think that functional foot typing as a theory is on the same level as tissue stress theory.

  3. drsha

    drsha Banned

    Allow me to put your statements to task.

    Fehnman States:
    Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong.

    You state in your first scientific statement that a valgus wedge is bad for those with posterior tibial tendon dysfunction (PTTD) and that varus wedges are good.
    Summarily, PTTD, never valgus wedge.
    In your second scientific statement, you say that valgus wedges reduce medial knee abduction moments (that leads to its use for medial knee pain (MKP) in tissue stress, correct?).
    Summarily, MKP, valgus wedge.

    Do you wish to promote PTTD in those with medial knee pain (MKP)?
    How do you decide when to apply your valgus wedges or do you robotically place them in MKP without knowing if it will produce PTTD?
    Do you robotically place a varus wedge or medial heel skive in everyone with PTTD without knowing if it will produce MKP?

    What do you do for patients with PTTD and MKP?

    What do you do when a patient with MKP begins to complain of PTTD?

    What do you do when a patient with PTTD begins to complain of MKP?

    I would argue that your tissue stress platform does not compare well to nature in Fehnman's definition of science (not to mention "Thou Shalt Not Harm", Hippocratically)..

    You are treating symptoms and complaints accepting the fact that your treatment will, in unknown numbers of cases, produce other complaints, which you will then treat in some other robotic manner only to produce some other area of tissue stress they will eventually complain of....vicious cycle.

    Your science has no sense of the BIO in Biomechanics.

    You are too eager to accept unwanted and damaging side effects and biomechanical consequences of your experiments upon your patients with a glib plan to add some other ORF's as they surface as you forewarn the patient of the tradeoffs you are fating them to.

  4. efuller

    efuller MVP

    Dennis, do you take any prescription medications and have you read the package insert? Do you prescribe any medications?

    I think you misunderstand Fennyman's definition of nature. You could replace nature with the phrase, the real world. Fennyman is describing one of the processes of science. You formulate a hypothesis, make predictions from that hypothesis and then compare that to the real world (nature).

    I have a patient with medial knee pain, a fairly significant genu varum, and sinus tarsi pain. He came to me for the sinus tarsi pain, I gave him an inverted heel cup orthotic. He came back saying his knee hurt. I removed some of the rearfoot post plantar medially, the knee pain went away. A few months later he came back with sinus tarsi pain. After a little trial and error we came up with the solution where he would tape a coin on the bottom of his rearfoot post when his sinus tarsi pain returned and he removes it when his knee hurts. I predicted that he might have knee pain when he first came to see me. I also predicted that his sinus tarsi pain would feel better with the orthotic. The observations in real life (nature) agreed with the hypothesis.

    Treatments have side effects. When you put an orthotic in a shoe, it may have unintended consequences. You can ignore the possibility, or you can try and figure out why it happens. When you take an NSAID you get an increased risk of bleeding. You have to weigh the potential cost versus the potential benefit and then alter the treatment if you are not happy with the results.

  5. efuller

    efuller MVP

    I found this other Feynman quote:

    Just because you give a foot type a name does not mean you know anything about it.

  6. More or less what Eric said. Especially

    Orthoses, all orthoses whether fft, root, pre fab or other, change forces. All orthoses aim to reduce stress in affected tissues. To do this they generally increase tissue stress in other tissues. These are inevitable truths.

    There is an important and valid debate between fft and ts, but it does not hinge around whether one style does harm or not IMO. A ts device with a medial wedge will have the same effect on the knee as a similar fft device with a medial wedge.

    The question for me is which formula for arriving at a prescription does most good and least harm, most of the time and for most people.
  7. drsha

    drsha Banned

    1. Since Fennyman died in 1988, I am wondering what gives you the poetic license or proof to claim to understand what his definition of "nature" was.
    Can,t you justify your claims scientifically?
    I think we should change the words to "in a clinical or experimental situation in the real world".
    Anyone else?

    2. I am trying not to be sarcastic but:
    Is this Rube Goldberg Rearfoot, Frontal Plane Biomechanics at its most robotic, rigid and absurd?
    Did you use a dime or a quarter?
    Do 2 dimes and a nickel have the same effect as a quarter?
    Do you use coins in your practice often? Any papers?

    Did you consider sagital plane correction of the sinus tarsitis? Transverse plane?
    Did you consider more shock absorbing materials to buffer the stress into the sinus tarsi?
    Did you consider an LLD and use a lift on the short side (remember, the coin acts a lift) which would have less effect on the postural complaint than a wedge?
    Did you offer physical therapy or rehab to the ankle or knee?
    Did you try synvisc or zeel or traumeel or cortisone at either site?
    Did you try additional strappings or bracings or other external aids?
    Did you try an alternative approach to the orthotic from scratch? Do you have any?
    Did you try an exercise program to strengthen the ankle or knee.
    Did you modify activity to include less biomechanically stressful tasks like biking or swimming?
    Did you ask the patient to consider weight reduction, behavioral modification or a change in shoe gear, terrain, performance style?

    My opinion here is that Dr. Fuller's biomechanical care in this case borders on negligence and malpractice.

    I would consider a functional foot typing of this patient and then using the foot type and the suggested options for care as a starting platform for care, select from the myriad of treatment variables that include casting, positive cast creation, shell fabrication, prescription and modification on all three body planes along with the adjacencies to orthotic care like muscle engine training, injection therapy, shoe gear modification, training program variables, etc, and set a goal for succes that includes a cure with no sequellae and if I got to the point where I could not accomplish this goal (looking for a coin to use on and off as in "It hurts when I do this----then don;t do this, do that, CONSULT to those with greater diagnostic and clinical accumen as myself.


    What is the science behind your use of coins. It sounds like a guessing game to me.

  8. C'mon Dennis. I suspect you don't really think that, you're just being provokative. You know you're never going to get a good debate out of anyone when you talk to them like that.
  9. David Smith

    David Smith Well-Known Member

    Q) What Is The Science Behind Biomechanics?

    A) Generally - Physics, specifically - Newtonian mechanics, precisely - the application of Newtonian mechanics to the mechanism of the body.

    End of:wacko:

    Last edited: Sep 4, 2011
  10. drsha

    drsha Banned

    Why Robert.

    Eric says he has reviewed my work and decided to pass.

    He admits that is based on reading one patent.

    Do you honestly believe if I did not express my opinion that he is negligent based on his arrogance and bias, he would be debating me fairly?




    I have submitted a chapter in a new text called The Diabetic Foot edited by a Harvard DPM entitled "The Biomechanics of The Diabetic Foot"

    I am invited to lecture at The AAD National ( "D" is Dermatology) for the second time (2006 was the 1st) delivering a Keynote Sectional Lecture entitled "The Biomechanics of Dystrophic Toenails".

    I have been invited to deliver an annual update to "Wellness Biomechanics" at The 2nd International Integrative Medicine Conference in Jeruselum.

    I remain The Biomechanics Editor of Present Podiatry for the third year.

    I run my practice to the benefit of my community.

    I am an Adjunct Clinical Professor at NYCPM

    I run my lab.

    I promote Podiatry and Biomechanics in America.

    Until I am judged fairly, I will remain the voice of opposition on The Arena to reveal that you have the same flaws that I am being accused of and the venom that I return to your snakes is the only poison they understand.

    I would leave Eric alone if he reciprocated (Kevin too)


  11. Do you honestly believe that people WILL "debate you fairly" when you accuse them of being negligent? Just for disagreeing with you?

    You know where I stand on FFT. I don't think its the best way for everyone to practice biomechanics. There are times I think you're wrong, as there are times you think I am wrong and that's OK. If we all agreed there would be no need for the arena.

    But negligence is a very big word. Just because I think you are wrong (on some things) does not mean I think you're negligent.

    Just take a breath, step back and chill a notch. Please? For me? This could be a useful discussion but only if we stick to debating the issues (which matter) rather than making potentially libellous swipes at each other. That will not encourage the sort of debate and consideration you appear to desire.
  12. Obviously not the correct ones.
  13. RobinP

    RobinP Well-Known Member

    The functional foot typing bit aside, why do you believe this is anything other than "treating patients"?
  14. Funny thing Dennis Eric may have asked you a 1000 times questions re FFT which you refuse to answer. People have asked for links to peer reviewed papers re FFT which you cannot provide.

    So I suggest you come back to us when you have a peer reviewed papers and maybe FFT could be discussed on the Arena.
  15. David Smith

    David Smith Well-Known Member

    Dennnis your argument is logically invalid, a fallacy, in the fact that your premises are true but your conclusion is false relative to the question based in the original hypothesis.

    First you put what must be a rhetorical question "What is the science behind biomechanics?" because you then obtusely answer it yourself by offering a quote that defines the philosophy of the scientific method. This unusual tactic leads you to infer that biomechanics, in terms the relationship between Newtonian mechanics and tissue stress, is not scientific, or at least, no more scientific than your own FFT system of clinical intervention for treatment of foot pain.

    This then would surely demand a comparison between the two in terms of the biomechanical principle behind each theory. Eric, in answer, does offer to defend the tissue stress model by using examples of how mechanics is used to treat certain pathology.

    Your next move should have been to describe how your FFT system achieves resolution of painful symptoms and how it is superior or equal to Newtonian mechanics. The absurdity here is that you apply the term biomechanics to your FFT system and at the same time dismiss mechanical principles applied to the mechanism of tissue stress as non scientific or not provable and yet, as I pointed out in my first post, this is exactly what biomechanics is. This would therefore suggest that your FFT cannot have biomechanical principles and since this is a logical conclusion then you should next show exactly what principle is applied by the FFT and the philosophy behind it.

    Presumably the philosophy would fulfil the criteria you set out in the quote you used at the beginning of your argument i.e. test the theory to see if it agrees with observation (and then BTW, test the probability that the correlation didn’t happen by chance, i.e. if observation disagrees with the theory its probably wrong, which is an important part of the scientific method that is not covered in the quote you used)
    So far Dennis you have not done this, this is not an unreasonable or unfair request, it is a necessary procedure to show you have a reasonable argument or even prove your proposal.

    But, instead you have used a related but unconnected argument known as an informal logical fallacy, where in itself its proposals or premise may be true but the conclusion, even though true within this closed singular argument, does support the universal proposal of your argument, its unrelated, and illogical in its application. This is, as you have been told before a straw man argument technique that appears to support your argument but in fact does not.

    “A straw man is a component of an argument and is an informal fallacy based on misrepresentation of an opponent's position. To "attack a straw man" is to create the illusion of having refuted a proposition by replacing it with a superficially similar yet unequivalent proposition (the "straw man"), and refuting it, without ever having actually refuted the original position.”
    To be precise you have used a dispute in the definition of a term within the Feyman quote that you used and other illogical distractions to avoid directly addressing the argument in the correct and logical way.

    If you can’t or won’t make a logical argument then it is a complete waste of time for anyone to engage with you. It’s like arguing that one person is a better boxer than another, you support the boxer Jim ‘No Nose’ Briggs and conclude that he is the best and this must be true because it can be argued and proved that the other boxer, Bob ‘Ripper’ Jackson cannot spell referee while wearing boxing gloves.

    I would be obliged if you would show how your FFT orthoses work without using biomechanical principles in terms of physics, Newtonian mechanics applied to the mechanism of the body.

    Regards Dave Smith
    Last edited: Sep 5, 2011
  16. Griff

    Griff Moderator


    Having digested your posts for several years and most recently reading the well structured, articulate and reasoned responses from individuals who I respect such as Eric, Robert and David I just wanted to add that I think you speak a load of old cock.

    As you were.
  17. Ian,

    I seem to recall somewhere in the distant past suggesting that Dennis was a good example of how shallow the Shavelson gene pool had become. Unfortunately, on current form, I suspect someone has since pulled the plug.

    Best wishes
  18. drsha

    drsha Banned


    thank you for taking the time to refute my words.

    I feel so comfortable with my position in that you do not take the same energy to refute the rest of the fallacy and lies and exaggerations and opinions and political and biased "certanties" that live on these pages.

    Why don't you take the one that Kevin wrote that I refuted and apply your same skills while resting your bias.

  19. drsha

    drsha Banned

    Time for a rest.

    The physical threats come next eh Chavies?

    Sorry Robert.

  20. Physical threats? I think you really are deluded and in need of psychiatric help if you think that. Actually, Dennis, I think you are an imbecile primarily, deluded in many ways certainly, but an unpleasant imature character who offers nothing to suggest any accumulation of wisdom or even wit was acquired along the journey. Your remarks to Mr Fuller earlier in this thread were a slight on his character and most probably defamatious, and if so, even though I don't particularly like civil litigation, I sincerely hope he sues the pants off you. I hasten to use the term cretin, Dennis, but I can think of no other more appropriate nome de guerre to give you. You have demonstrated nothing of note during your time on this forum other than behaviour that certifies that fact.

  21. David Smith

    David Smith Well-Known Member


    I'm not refuting your words I'm pointing out to you that your argument is wasted energy because it makes no sense. This could be seen as useful guidance because now you can change your argument.

    I expect we all fall foul of illogical and biased argument at some time but when someone continuously makes the same mistake it would be useful for someone to point out that mistake. However when that person continues to make the mistake it may or can no longer be excused as a faux pas but be received as a deliberate, carte blanche attempt to deceive, for which, the appropriate response is given i.e. your not worth listening to! Which for someone who demands to be heard is hard to accept and results in their angry, hard done by, response but incredibly, still arrogantly refuses to offer any answer that comes close to logically answering original or subsequent questions..

    Regards Dave
  22. drsha

    drsha Banned

    Please all readers, look at Marks anger and rage and understand why I must tread lightly at this time.

    Look at who THANKS him for delivering them...
    Fuller, Spooner et al.
    Think of how many of them are thanking him in silence.

    I wonder how many of you are not brave enough to THANK me but are thanking me in silence?

    Especially you students who look up to your leaders who are doing nothing to edit his harsh words about me.
    We all know that I am not an Imbecile!

    In addition, he writes words of wisdom and explains one of my places on The Arena.

    It is to expose when it falls foul of illogical and biased argument as I will continue to do as I monitor.

  23. All readers, N.B. The only person who has thanked Mark for any of his postings in this thread is David W. The above posting is just another example of the fallacies that Dennis Shavelson creates and his inability to see past his own anger and ego well enough to actually read the postings made by others.

    Don't bother thanking me, Dennis; nor replying. I have absolutely no time for your callow games.
  24. davsur08

    davsur08 Active Member

    I would consider a functional foot typing of this patient and then using the foot type and the suggested options for care as a starting platform for care, select from the myriad of treatment variables that include casting, positive cast creation, shell fabrication, prescription and modification on all three body planes along with the adjacencies to orthotic care like muscle engine training, injection therapy, shoe gear modification, training program variables, etc, and set a goal for succes that includes a cure with no sequellae and if I got to the point where I could not accomplish this goal (looking for a coin to use on and off as in "It hurts when I do this----then don;t do this, do that, CONSULT to those with greater diagnostic and clinical accumen as myself.


    How do these myriad of treatments you have listed from casting to muscle engine training different from what Dr.Fuller's treatment for sinus tarsi pain? or medial knee pain. how do you formulate your treatment using the 'functional foot typing'? Potato/potaeto???
  25. Sheesh. I turn my back for a few days.

    I'm not sure that this thread is savable, in terms of bringing it back to a thread which can actually educate or entertain. But I will say this.

    I am not a fan of FFT. Never have been. However most of the problems people have had with each other on this and the other threads like it have more to do with the arguments themselves than the topics under discussion.

    I feel that we may be as blinded to the potential benefits of FFT, and there ARE some potential benefits of FFT, as Dennis is to the virtue of the tissue stress model, because of the nature and tone the argument has taken on. In essence, we've got to the point where we are just arguing with each other, rather than arguing about the issues.

    When an argument gets like that, it becomes impossible to make any comprimises, concessions or properly consider the others point of view because an attack on the concept has become an attack on the individual and the consession of a point becomes a concession of personal error or inadequacy.
  26. David Smith

    David Smith Well-Known Member


    I am not against foot typing per se and in fact I bought a Talar Made Quadrastep system because I thought it might be useful and I would give it a go. I paid good money for it which is always a good indication of open mindedness I think.

    Talar Made's philosophy is that certain foot types correlate with certain foot and leg pathologies. It might be reasonable to assume that a foot type that causes supination might result in peroneal trauma for instance. The same foot type may also induce saggital plane progression perturbation and so have concomitant pathology e.g. Achilles tendonosis. There are many times when this will not be so but Talar Made propose that most of the time it will apply and the reduced cost of the orthoses and the reduced design and fitting result in a cost Vs outcome ratio consideration that makes these orthoses worth using.

    I use them in a slightly different way, I consider what is the tissue that is symptomatic and then, using biomechanical principles, how the pathology is being caused. Then, if there is a suitable orthosis in the Quadrastep range, in terms of its biomechanical affect on the foot and its fit for the type of foot, I will use it when there is a consideration of total cost to be taken into account. I.E> the customer can't afford bespoke orthoses or bespoke orthoses would, in my opinion, result in no better outcome in terms of pain resolution, gait progression or increase in comfort or usage longevity.

    This outlines a philosophy and method and can be used as a basis for a logical argument. It is not that difficult to do, perhaps you would like to reciprocate.

    Regards Dave Smith
  27. RobinP

    RobinP Well-Known Member

    What I cannot understand about foot typing is what it acheives.

    I feel the same about looking at forefoot to rearfoot relationships.

    What difference does that piece of information make to how I intend to treat this patient.

    I agree with the concept of the quadrastep system in terms of a cost/benefit prescription and I would use it in the same way as David.

    My question for Dennis is, does the foot type, you deem someone to have, restrict them to having a particular type of device, regardless of the injured structure?

    If so, then it falls down on the same principles of the quadrastep system if you stick and prescribe rigidly according to the type of foot they would appear to have.

    If not, then what is the point in "typing" the foot?

    Genuine question, not just looking to be obtuse

  28. David Smith

    David Smith Well-Known Member

    None as far as the biomechanical effect is concerned, however the type or shape of relative alignment or relative joint stiffness might be relevant in terms of the particular design one uses to achieve a certain biomechanical effect.
  29. I have been purposefully staying out of this discussion since I don't waste any more of my time trying to discuss anything with Dr. Shavelson.

    That being said, Mark, your observation above certainly hits the nail squarely on the head. I just wanted to acknowledge that you, again, often make the best posts here on Podiatry Arena.:drinks
  30. Admin2

    Admin2 Administrator Staff Member

    This thread has run its course. Its going no where. Unless someone has something new to say or Dennis actually wants to answer the questions he has been repeatedly asked, it will remain closed.
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