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Skives and posts

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Ann PT, Jun 7, 2006.

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  1. efuller

    efuller MVP

    This looks at position and not moments. A wedge under the heel of the foot will shift the location of center of pressure under the foot. (unpublished data) There is also published data in this area. (Irene McClay) So even though position may not change the moment and internal stresses will change.


    Agreed, positional measurement is not very good. This does not discount the idea that the moment is changed by the wedge. Ed, how does the orthosis made with your design change the moments applied to the foot. If you see supination motion with the orthosis and there was no supination motion without the orthosis there had to be a change in the moment. What causes this change?

    You are comparing apples to oranges. The post and/or wedge alters the location of the center of pressure under the foot which alters the moment at the subtalar joint. If you move a force that is 3 times body weight 1mm more medial you don't need any more time than the length of the step to change the stress on anatomical structures. You don't change body weight, you change the location of where it is applied. The time argument is not valid.

    When you look at a pressure distribution map during gait, the software can calculate the location of the center of pressure throughout the step. A 1mm medial shift in the location of the center of pressure will be hardly visable with a quick glance, but can be quantified. A 1mm shift times body weight will make a significant change in the moment from ground reaction force.

    How does the orthosis apply moments to the foot to "place" the foot in a more supinated position? How does standing on an orthosis with a really high arch create a supination moment about the STJ? (Shifts COP more medial and or induces pain avoidence response and an increase in supination muscle activity. Where do you see the wear on the orthosis?)

    Regardless of what you stand on, there is always an equal and opposite force from the ground/orthotic. I don't understand what you are saying about equal and opposite force.

    You make fun of the engineer Spongebob Squarepants to make your point. Both sides of this debate should attack the idea and not the person. (You owe Spongebob an apology) I disagree with your points about rearfoot posts above. What is your answer to my rebuttal?

    Respectfully,
    Eric Fuller
     
  2. Ed:

    Hope you had a good time with your family on your vacation. By the way, were you invited to give the presentation at the Western Podiatry Congress in Anaheim this last weekend or did you pay to have an opportunity to exhibit and lecture at the meeting?

    As far as personal attacks go, I don't think I have made any personal attacks on you. I have only made observations and expressed my opinions from the DVD that you sent out to me, from your lack of published research and from what other podiatrists have told me about you and your lectures. Maybe I am telling you things that podiatrists that I respect are saying about you but are afraid to tell you in public or private. However, certainly my comments so far can't be considered personal attacks. I am sorry if I have offended you but I often do tend to be perceived to be quite abrasive to some individuals, maybe because I am not afraid to speak my opinion regarding their ideas.

    I am anxious to discuss your dialogue from your DVD. The first thing you say in your DVD which is false, misleading and quite insulting to the many authors who have spent years doing foot orthosis research is "Scientific studies have shown that foot orthotics don't work". You then go to quote the Pfeffer et al study which was funded by the foot and ankle orthopedic society here in the States, which has multiple flaws associated with it, as an example of research that shows that "foot orthotics don't work". In your DVD, you totally disregard the abundance of research which shows that not only do foot orthoses work to relieve symptoms, but they have also been shown to improve balance, decrease pain, relieve painful symptoms and to effectively change both the kinetics and kinematics of gait. Here is my reference list from a paper that will be published next month in Foot and Ankle Quarterly, "Foot Orthoses: Therapeutic Efficacy, Theory and Research Evidence for their Biomechanical Effect" that I was invited to write by Paul Scherer, DPM, (who you also criticize in your DVD) for the lead article in the upcoming edition of the FAQ. I suggest that you would improve your level of education if you started reading some of the following research articles that show that foot orthoses "do work" and then tell me, after reading these articles, if you still feel that "foot orthotics don't work":

    1. Baitch SP, Blake RL, Fineagan PL, Senatore J: Biomechanical analysis of running with 25 degree inverted orthotic devices. JAPMA, 81:647-652, 1991.
    2. Bates BT, Osternig LR, Mason B, James LS: Foot orthotic devices to modify selected aspects of lower extremity mechanics. Am J Sp Med, 7:328-31, 1979.
    3. Blake RL, Denton JA: Functional foot orthoses for athletic injuries: A retrospective study. JAPMA, 75:359-362, 1985.
    4. Blake RL: Inverted functional orthoses. JAPMA, 76:275-276, 1986.
    5. Blake RL, Ferguson H: Foot orthoses for the severe flatfoot in sports. JAPMA, 81:549, 1991.
    6. Blake RL, Ferguson H: The inverted orthotic technique: Its role in clinical biomechanics., pp. 465-497, in Valmassy, R.L.(ed.), Clinical Biomechanics of the Lower Extremities, Mosby-Year Book, St. Louis, 1996.
    7. Butler RJ, McClay-Davis IS, Laughton CM, Hughes M. Dual-function foot orthosis: Effect on shock and control of rearfoot motion. Foot Ankle Intl, 24:410-414, 2003.
    8. Chalmers AC, Busby C, Goyert J, Porter B, Schulzer M: Metatarsalgia and rheumatoid arthritis-a randomized, single blind, sequential trial comparing two types of foot orthoses and supportive shoes. J Rheum, 27:1643-1647, 2000.
    9. Cheung JT, Zhang M: A 3-dimensional finite element model of the human foot and ankle for insole design. Arch Phys Med Rehabil, 86:353-358, 2005.
    10. Dananberg HJ, Guiliano M: Chronic low-back pain and its response to custom-made foot orthoses. 89:109-117, 1999.
    11. D’Ambrosia RD: Orthotic devices in running injuries. Clin. Sports Med., 4:611-618, 1985.
    12. Donnatelli R, Hurlbert C, et al: Biomechanical foot orthotics: A retrospective study. J Ortho Sp Phys Ther, 10:205-212, 1988.
    13. Dorland’s Illustrated Medical Dictionary, 25th ed., W.B. Saunders, Philadelphia, 1974.
    14. Duffin AC, Kidd R, Chan A, Donaghue KC: High plantar pressure and callus in diabetic adolescents. Incidence and treatment. JAPMA, 93:214-220, 2003.
    15. Dugan RC, D’Ambrosia RD: The effect of orthotics on the treatment of selected running injuries. Foot Ankle, 6:313, 1986.
    16. Eggold JF: Orthotics in the prevention of runner’s overuse injuries. Phys. Sports Med., 9:181-185, 1981.
    17. Fuller EA: Center of pressure and its theoretical relationship to foot pathology. JAPMA, 89 (6):278-291, 1999.
    18. Fuller EA: Reinventing biomechanics. Podiatry Today, 13:(3), December 2000.
    19. Gross ML, Davlin LB, Evanski PM: Effectiveness of orthotic shoe inserts in the long distance runner. Am. J. Sports Med., 19:409-412, 1991.
    20. Gross MT, Byers JM, Krafft JL, Lackey EJ, Melton KM: The impact of custom semirigid foot orthotics on pain and disability for individuals with plantar fasciitis. J Ortho Sp Phys Ther, 32:149-157, 2002.
    21. Guskiewicz KM, Perrin DH: Effects of orthotics on postural sway following inversion ankle sprain. J Orthop Sp Phys Ther, 23:326-331, 1996.
    22. Hertel J, Denegar CR, Buckley WE, Sharkey NA, Stokes WL: Effect of rearfoot orthotics on postural control in healthy subjects. J Sport Rehabil, 10:36-47, 2001.
    23. Kilmartin TE, Wallace WA: The scientific basis for the use of biomechanical foot orthoses in the treatment of lower limb sports injuries-a review of the literature. Br. J. Sports Med., 28:180-184, 1994.
    24. Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987.
    25. Kirby KA: Rotational equilibrium across the subtalar joint axis. JAPMA, 79: 1-14, 1989.
    26. Kirby KA, Green DR: Evaluation and Nonoperative Management of Pes Valgus, pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992.
    27. Kirby KA: The medial heel skive technique: improving pronation control in foot orthoses. JAPMA, 82: 177-188, 1992.
    28. Kirby KA.: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997.
    29. Kirby KA.: Biomechanics and the treatment of flexible flatfoot deformity in children. PBG Focus, J. Podiatric Biomechanics Group, 7:10-11, 1999.
    30. Kirby KA: Conservative treatment of posterior tibial dysfunction. Podiatry Management, 19:73-82, 2000.
    31. Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001.
    32. Kirby KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, AZ, 2002.
    33. Kirby KA: Lateral heel skive orthosis technique. Precision Intricast Newsletter. Precision Intricast, Inc., Payson, AZ, September 2004.
    34. Laughton CA, McClay-Davis IS, Hamill J: Effect of strike pattern and orthotic intervention on tibial shock during running. J Appl Biomech, 19:153-16, 2003.
    35. Lee WE: Podiatric biomechanics: an historical appraisal and discussion of the Root model as a clinical system of approach in the present context of theoretical uncertainty. Clin Pod Med Surg, 18:555-684, 2001.
    36. Li CY, Imaishi K, Shiba N, Tagawa Y, Maeda T, Matsuo S, Goto T, Yamanaka K: Biomechanical evaluation of foot pressure and loading force during gait in rheumotod arthritic patients with and without foot orthoses. Kurume Med J, 47:211-217, 2000.
    37. Lobmann R, Kayser R, Kasten G, Kasten U, Kluge K, Neumann W, Lehnert H: Effects of preventative footwear on foot pressure as determined by pedobarography in diabetic patients: a prospective study. Diabet Med, 18:314-319, 2001.
    38. MacLean CL, Hamill J: Short and long-term influence of a custom foot orthotic intervention on lower extremity dynamics in injured runners. Annual ISB Meeting, Cleveland, September 2005.
    39. McCulloch MU, Brunt D, Linden DV: The effect of foot orthotics and gait velocity on lower limb kinematics and temporal events of stance. J Ortho Sp Phys Ther, 17:2-10, 1993.
    40. McPoil TG, Hunt GC: Evaluation and management of foot and ankle disorders: Present problems and future directions. JOSPT, 21:381-388, 1995.
    41. Mejjad O, Vittecoq O, Pouplin S, Grassin-Delyle L, Weber J, Le Loet X: Foot orthotics decrease pain but do not improve gait in rheumatoid arthritis patients. Joint Bone Spine, 71:542-545, 2004.
    42. Moraros J, Hodge W: Orthotic survey: Preliminary results. JAPMA, 83:139-148, 1993.
    43. Morton DJ: The Human Foot: Its Evolution, Physiology and Functional Disorders. Columbia University Press, New York, 1935.
    44. Mundermann A, Nigg BM, Humble RN, Stefanyshyn DJ. Foot orthoses affect lower extremity kinematics and kinetics during running. Clin Biomech, 18:254-262, 2003a.
    45. Mundermann A, Nigg BM, Humble RN, Stefanyshyn DJ: Orthotic comfort is related to kinematics, kinetics, and EMG in recreational runners. Med Sci Sports Exercise, 35:1710-1719, 2003b.
    46. Mundermann A, Wakeling JM, Nigg BM, Humble RN, Stefanyshyn DJ: Foot orthoses affect frequency components of muscle activity in the lower extremity. Gait and Posture, In Press, 2005.
    47. Nawoczenski DA, Cook TM, Saltzman CL: The effect of foot orthotics on three-dimensional kinematics of the leg and rearfoot during running. J Ortho Sp Phys Ther, 21:317-327, 1995.
    48. Nawoczenski DA, Ludewig PM: Electromyographic effects of foot orthotics on selected lower extremity muscles during running. Arch Phys Med Rehab, 80:540-544, 1999.
    49. Nester CJ, Hutchins S, Bowker P: Effect of foot orthoses on rearfoot complex kinematics during walking gait. Foot Ankle Intl, 22:133-139, 2001.
    50. Nester CJ, Van Der Linden ML, Bowker P: Effect of foot orthoses on the kinematics and kinetics of normal walking gait. Gait Posture, 17:180-187, 2003.
    51. Novick A, Kelley DL: Position and movement changes of the foot with orthotic intervention during loading response of gait. J Ortho Sp Phys Ther, 11:301-312, 1990.
    52. Nigg BM: The role of impact forces and foot pronation: a new paradigm. Clin J Sport Med, 11:2-9, 2001.
    53. Payne CB: The past, present, and future of podiatric biomechanics. JAPMA, 88:53-63, 1998.
    54. Postema K, Burm PE, Zande ME, Limbeek J: Primary metatarsalgia: the influence of a custom moulded insole and a rockerbar on plantar pressure. Prosthet Orthot Int, 22:35-44, 1998.
    55. Powell M, Seid M, Szer IA: Efficacy of custom foot orthotics in improving pain and functional status in children with juvenile idiopathic arthritis: A randomized trial. J Rheum, 32:943-950, 2005.
    56. Rome K, Brown CL: Randomized clinical trial into the impact of rigid foot orthoses on balance parameters in excessively pronated feet. Clin Rehab, 18:624-630, 2004.
    57. Root ML, Orien WP, Weed JH, RJ Hughes: Biomechanical Examination of the Foot, Volume 1. Clinical Biomechanics Corporation, Los Angeles, 1971.
    58. Root ML: How was the Root functional orthotic developed? Podiatry Arts Lab Newsletter, 1981.
    59. Saxena A, Haddad J: The effect of foot orthoses on patellofemoral pain syndrome. 93:264-271, 2003.
    60. Schuster RO: A history of orthopedics in podiatry. J Am Pod Assoc, 64:332, 1974.
    61. Sgarlato TE (ed): A Compendium of Podiatric Biomechanics. California College of Podiatric Medicine, San Francisco, 1971.
    62. Slattery M, Tinley P: The efficacy of functional foot orthoses in the control of pain and ankle joint disintegration in hemophilia. JAPMA, 91:240-244, 2001.
    63. Smith LS, Clarke TE, Hamill CL, Santopietro F: The effects of soft and semi-rigid orthoses upon rearfoot movement in running. JAPMA, 76:227-232, 1986.
    64. Stackhouse CL, Davis IM, Hamill J: Orthotic intervention in forefoot and rearfoot strike running patterns. Clin Biomech, 19:64-70, 2004.
    65. Thompson JA, Jennings MB, Hodge W: Orthotic therapy in the management of osteoarthritis. JAPMA, 82:136-139, 1992.
    66. Tomaro J, Burdett RG: The effects of foot orthotics on the EMG activity of selected leg muscles during gait. J Ortho Sp Phys Ther, 18:532-536, 1993.
    67. Walter JH, Ng G, Stoitz JJ: A patient satisfaction survey on prescription custom-molded foot orthoses. JAPMA, 94:363-367, 2004.
    68. Williams DS, McClay-Davis I, Baitch SP: Effect of inverted orthoses on lower extremity mechanics in runners. Med. Sci. Sports Exerc. 35:2060-2068, 2003.
    69. Woodburn J, Barker S, Helliwell PS: A randomized controlled trial of foot orthoses in rheumatoid arthritis. J Rheum, 29:1377-1383, 2002.
    70. Woodburn J, Helliwell PS, Barker S: Changes in 3D joint kinematics support the continuous use of orthoses in the management of painful rearfoot deformity in rheumatoid arthritis. J Rheum, 30:2356-2364, 2003.

    In the time I have remaining in reviewing your DVD, you quote a study from a paper titled "Orthoses reduce pressure but fall short of biomechanical correction" from Biomechanics Magazine in October 2000 http://www.biomech.com/db_area/archives/2000/0010sports.59-68.bio-.html

    What the authors actually said in their article was as follows:

    and what you said in your DVD when you were supposedly quoting from the paper was as follows: "...in contrast, the orthoses in this study seem to reduce plantar pressure in these areas, actually making the gait cycle worse."

    Now, Ed, where did you get from this paper that the authors said that the orthoses made the gait cycle worse?? To me, in reading this paper, it seems like the authors were being very speculative (i.e. guessing) as to whether changes made in the temporal pattern of pressure on the plantar foot with the foot orthoses were negative effects or not. However, you add in the comment, not in the author's paper, that foot orthoses were "actually making the gait cycle worse".

    Are you assuming that just because their is a redirection of pressure on the plantar foot caused by orthoses that this also indicates that this makes the gait cycle worse?? I didn't read that anywhere in the article you quote by Tis, Higbie, Chadwick and Johnson. In fact the authors, are quite right in asking the questions in their paper in view of their results. However, it seems like you are claiming in your DVD that if the foot orthosis moves pressure away from the hallux and first metatarsal then this means that the "gait cycle is worse"? This is false, misleading and even worse, I believe it misrepresents what Root, Weed and Orien taught for years to podiatrists here in the States and abroad.

    I had the great fortune to have attended many lectures and to have been personally taught by Drs. Merton Root, John Weed and Bill Orien. I can tell you that they never once said that it is normal for the hallux and first metatarsal to get all the pressure at any time during gait. In addition, they never once said that if the orthosis moves the pressure away from the hallux and first metatarsal that the orthosis is functioning abnormally. I think that you are assuming quite a bit here and making quite large leaps in your guesses on normal and abnormal biomechanics. Basically, it seems that your are attempting to prove your point that orthoses don't work by bending the words of others, by misquoting the research of other researchers, and by ignoring the huge body of research that shows that foot orthoses are not only therepeutically effective but also significantly alter both the kinematics and kinetics of gait. Maybe if you came to reasonable conclusions, didn't seem to be distorting the facts to show that your orthotic product is somehow better than others, especially considering your lack of published research to demonstrate otherwise, then I wouldn't be perceived by you as someone that only wants to attack you personally.

    That's all for now. Hope you had a pleasant time with your family in your visit to the Western Podiatry Congress. Looking forward to your comments to me, Eric Fuller, Simon Spooner and Dave Smith.

    By the way, just to let you know, Simon Spooner, PhD, probably prefers to be called by his first name, Simon, instead of what you have been calling him in all of your postings to him (i.e. Spooner). I would suggest that you would do well to be more careful in the future as to how you address respected academics in public who lecture nationally and internationally on biomechanics.
     
  3. I can't believe I missed this earlier. On the one hand to try and prove your theory you are sayning that the STJ does not have an axis of motion and then as above, you are saying that it does have an axis, but the lever arm= zero- love this bending of the arguments.

    Anyway, how do you know that there is a zero net moment about the STJ axis at this point? How are you tracking STJ axial position and measuring internal STJ moment?



    Ed, I think very few of my colleagues, certainly not the ones who contribute to this list, actually believe in the concept of adding a 4 degree post to 4 degree varus resulting in 4 degree correction anymore. Like I said, things have moved on.
     
  4. Phil Wells

    Phil Wells Active Member

    Ed
    I always like a challenge so I'll join the others in a few questions.
    I am concentrating more on your orthoses design and the global impact they may have.

    The extreme 'earthquake' approach to orthotic prescriptions 'may' be appropriate for localised foot motion but what if the excessive motion is being driven by a more proximal pathology?
    EG. Patients with weak Gluteus medius function - seen a lot in HAV patients - will move their COM medially causing a massive pronation moment in the foot/STJ. This will happen sequentially with the knee internally rotating after the hip. If the foot is then held in a maximaly inverted position, the torque through the tibia/femur may be extremely destructive - tibia/femur interface or STJ.
    Similarly, if the foot is not allowed to pronate/evert at heel strike, the massive GRF generated in gait will be re-directed laterally into structures not designed for this type of loading.


    Cheers

    Phil
     
  5. EdGlaser

    EdGlaser Active Member

    Your criticism is a validation of my work

    Dear Simon,

    Correct… I am guilty of being consistent with my website.

    In the DVD and all of my writings I describe the TN joint as having an infinite number of axis. There are some excellent 3D graphics of this. Any axis that passes through the center of the ball in a ball and socket joint is a valid axis. What is the importance of an instantaneous axis in gait? I guess it would be important if all of gait happened in one instant. The fact the the degrees of freedom of motion are not restricted to a single axis is the point here. Your reference only serves to strengthen my argument.

    Who ever described the translation as dominant? Certainly not me. In fact Craig classifies me as one of the sagital plane theorists….meaning that the dominant motion is a predominantly sagital plane rotation around the posterior facet cone. The limited translational motion only serves to create an eversion moment using the leverage of the middle facet’s position (out on a lever arm of the sustentaculum tali, to increase torque). Regarding the helical axis…. I certainly disagree with the early researchers. Although both motions do occur….. they do NOT occur equally at the same time. At heel contact, in supination the talar head is resting on a relatively level anterior facet and therefore cannot allow much sagital plane rotation around the cone shaped posterior facet, except that facilitated by decrease in calcaneal inclination angle. As the calcaneus everts and the anterior facet is tilted, the talar head slides down the facet and disarticulates. This allow the Dominant motion to occur which is the sagital plane rotation around the posterior facet. You seem to be straining to misinterpret my work. I, in fact, criticize the helicoidal axis as being an oversimplification.

    Translation is not dominant…as I have stated. Ligamentous binding is not enough to limit the small amount of translation necessary to create the effect I describe and you are suggesting the evolution of the foot is keeping up with the changes in surfaces in modern culture….that’s a stretch.

    The “bundle of axes” is in direct agreement with my work. Thank you. Which one of the bundle are you mapping on the plantar surface of the foot? By the way, I like your device….I would love to get one… Is it available?


    When we looked at 210 calcaneus specimins at the Smithsonian Institute and measured the angulation of the three facets we noticed many that did not have a little interruption of the articular surface between the middle and anterior facets. Although this was the case, there were still two very distinct planes of articulation. When they were joined, it was easy to differentiate these two very distinct functional entities. The tiny space that is between most people’s middle and anterior facets is without function. Force is still transduced the same as it passes from middle to anterior.

    I don’t pretend to be as well read as yourself. Do not assume however that I have not read a lot of the articles you reference… I have. Nothing I have said would indicate otherwise….just a poor assumption. It is hard to use existing literature to evaluate my theories or product because Sole Supports is an aggressive technology that puts the foot in an entirely new position: the MASS position. This is the position of maximal supination that the patient can tolerate with their anatomy at midstance. This position has an effects many functional parameters including: the keystone of the navicular, the angle and mechanical advantage of many tendons, the position of some axes, the angulation and magnitude of various forces as well as tissue stresses.


    Or theirs....I will have to visit or revisit and evaluate each of these studies. What I suspect is that the statistically significant results are only significant statistically. The titles would indicate that these studies actually strengthen my case. I hold that standard rootian orthoses with wedges and posts in the frontal plane actually act by allowing the foot to almost fully pronate and then block the last few degrees of pronation. You take the amost fully pronated foot and then try to effect it by tilting the ground a few degrees, so you are walking along the roof peak. Have you walked outside lately. I bet every step the ground varies more on the frontal plane than sum of your postings and wedgings. This seems to be what theses studies are indicating. It is also what your “tissue stress” model indicates as well. When joints reach the end of their ROM they put stress on tissues that cause deformities. By blocking the last few degrees of pronation…less stress, removes the causative factor but does it cause an appreciable change in function? Will it reverse deformity?

    This is fun.

    It’s as if the current technology is like moving earth with a teaspoon. and the frontal plane theorists have made their career studying the handle and grip of the spoon. In fact a statistically significant improvement of 15% dirt moving efficiency is made with some slight variation in frontal plane angle of the spoon in relation to the handle. Great careers are built on this and then some outsider comes along with a backhoe and claims to be able to move more dirt. It is easy to see more dirt being moved but the frontal plane theorists argue that the guy with the backhoe must be wrong because he makes money or hasn’t published an article, or hasn’t read everything ever done on spoons. The fact is that….he is too busy moving dirt. You act as though this is a childish debate about who is right. I have my attention on one thing. Developing a product that clinically stands alone as the most effective functional orthotic ever produced …. Bar NONE. I am consistent especially with my core value: “WE MAKE PEOPLE BETTER” This is not a chess game…what hangs in the balance is people’s health. Take a fresh LOOK at what I have done without the defensiveness of worrying that your life’s work has just been invalidated.

    Think about it!!! While you are tilting the ground a few degrees…..I am supinating the rearfoot, making the foot function better. If you LOOK at the DVD we have approached this from a clinical perspective….an embryologic perspective….and a physics perspective. They all agree and then they agree with the results we are getting….How else could be be growing at the rate we are without any advertising. If I was full of crap, I might be able to convince many docs to TRY our technology….but why do they stick with it….year after year even though we are more expensive than other labs…..they don’t get any secret payments from us to use our technology…they want what is most effective for their patients….I deliver that Hands Down. We are actually all on the same side...trying to make people better. The rules are different in academia than they are in the commercial world. We have no time for IRB's, grant proposals, five year studies, peer review .... In the clinic you want WHAT WORKS. This technology is hard to beat.

    For the benefit of those reading this...I will take each of the criticism of my four reasons why posting is a fantasy separately. I don't have time to rebut them as fast as they are being posted because my lecture schedule is so demanding and I have a growing company to run and mostly people to make better and more technology to invent. I have obviously struck a nerve here...I expected that.

    Thank You,
    Ed
     
  6. Phil:

    A common podiatric misconception is that if the center of mass (CoM) is positioned medial to the foot, that this somehow causes subtalar joint (STJ) pronation. I was also taught this erroneous concept in podiatry school. In fact, a CoM that is more medially positioned relative to the foot may, in fact, cause more STJ supination moment.

    If you read the paper I published recently in JAPMA with Bart Van Gheluwe and Friso Hagman of Belgium, you will find that when the subjects walked with a simulated genu valgum gait (i.e. when the CoM was more medial to the foot than normal), then an increased medially directed shearing force was generated on the foot from the ground that would tend to cause an increase in STJ supination moment in late midstance (Van Gheluwe B, Kirby KA, Hagman F: Effects of simulated genu valgum and genu varum on ground reaction forces and subtalar joint function during gait. JAPMA, 95:531-541, 2005). Therefore, using the position of the CoM relative to the foot is not a reliable way to determine the magnitude and/or direction of STJ moments as we all might have been previously taught.

    Hope this makes sense as I certainly think this is one of the many "podiatry myths" that Craig Payne may want to add to his list.
     
  7. efuller

    efuller MVP

    The TN joint is not relevent to the STJ axis discussion. The talo calcaneal joint has a bundle of axes that is relevent to our discussion. When the line of action of force is moved from one position to another more medial position the moment about all of the axes in the bundle will change. The importance of the bundle is that all of the motion observed occurs about an axis that does not change very much. So, a shift in the location of the force relative to the bundle will still alter the moment about the joint. The fact that all of the axes can be grouped in a bundle supports the notion that the joint can be treated as a hinge, just not a perfect hinge. Are you saying the STJ is not a hinge like joint about which moments occur?

    How does the orthosis "put" the foot into this entirely new position? How many degrees, on average, is this position different from RCSP without an orthosis? Is this amount high enough to even get to the point where we can start discussing facets of the talo calcaneal joint?

    Are you saying that your devices invert the foot more than root devices? Do you have data?

    Ed, I constantly question my assumptions. Do you? I know what it would take for me to change my mind about what I beleive. What would it take for you to change your mind?

    A couple of points.
    Ed, You can call it education, but going out and sponsoring yourself to lecture all over the country would be considered advertising by some.

    Only a very small percentage of people think critically when they hear about a new product.

    I had a pair of devices made for me using the Root paradigm. They made me feel better. I disagree with a lot of the theory used in the making of the devices, yet they still worked. They feel even better with a medial heel skive. A lot of people feel better with OTC devices. There is more than one way to make the foot feel better. Ed, you have an improvement in your manufacturing process, that will make the difference for some people, but maybe not everyone.

    Respectfully,

    Eric Fuller
     
  8. Phil Wells

    Phil Wells Active Member

    Kevin
    Thanks for the info. I'll try and get the actual paper but I am limited in my access to papers at the moment.
    Just to help clarify this is my mind, goes the medially directed shearing force only occur at late midstance?. If not, what effect does the medial CoP have on the STj at initial to mid contact and is it something that I need to be aware of?
    Also in the wider base of gait e.g. during pregnancy, does the same hold true?

    Thanks

    Phil
     
  9. davidh

    davidh Podiatry Arena Veteran

    Ed,
    Hi.

    You wrote (about Simon Spooner):
    "You seem to be straining to misinterpret my work".
    Do you know? I found this too :confused: .
    But in fairness to Simon, unless I publish my research findings I can't really answer back.

    I find it astounding, for example, that people don't look at the Homo Erectus skeleton (Turkana Boy), see the resemblance between his lower limbs and ours, look at the time differential (1.6 million years), and think "wow, our lower limbs haven't evolved that much after all".
    Even more astounding, how many on this forum have actually bothered to Google Turkana Boy?? :eek:

    Off to find a co-author!
    Regards,
    davidh
     
  10. davidh

    davidh Podiatry Arena Veteran

    Eric,
    You wrote:
    "I had a pair of devices made for me using the Root paradigm. They made me feel better. I disagree with a lot of the theory used in the making of the devices, yet they still worked."

    Same here - still wear them in fact :)

    Regards,
    davidh
     
  11. In our study, the medially directed shearing force, or ground reaction force (GRF), occurred throughout stance phase with the simulated genu valgum gait. However, the center of pressure (CoP) shifted more laterally in the heel contact (first GRF peak) which negated the supination effect from this medially directed GRF. During late midstance-early propulsion (second GRF peak) the inclination angle of the STJ axis gave the medially directed GRF vector enough supination moment arm to cause an increase in STJ supination moment, through our calculations. (Send me your email address and I'll send you a pdf of the paper.)

    To see for yourself that having the center of mass (CoM) medial to the foot does not cause a pronation effect on the foot, stand up and place your feet at progressively wider distances away from each other. As you increase the base of standing, the CoM becomes more medial to the feet. However, what is observed is a greater STJ supination effect on the foot due to the concomitant increase in medially directed GRF vector on the plantar foot causing an increase in STJ supination moment. This is a nice demonstration for teaching these concepts to podiatry students, podiatrists and even podiatrists who pay seminar organizers throughout their country to allow them to lecture. :rolleyes:

    Now, to see the effects of STJ axis height from the ground using this effect, put on a shoe with as thick of a sole as possible and then perform the same "wide base of standing" experiment. You will notice that for a given width of base while standing, the supination effect is increased on the foot when compared to barefoot. This is caused by the increased STJ supination moment arm that the medially directed GRF has to cause a STJ supination moment.

    Practically, this information can be used when recommending shoegear. If you have a patient who is involved in side-to-side sports such as soccer (i.e. football), basketball, etc. and they have a history of inversion ankle sprains, then it is best to try to keep their foot as low to the ground with thin-soled shoes to minimize the STJ supination moments from their side-to-side cutting maneuvers during their physical activity. In other words, I always recommend that patients don't play basketball or soccer in running shoes (that have thick soles) due to the increased risk of inversion ankle sprains.

    Hope this helps with the theory and practical application of how understanding the effects of the position of the CoM relative to the foot may be beneficial for the podiatrist.
     
  12. Ed,

    Sorry you had to cut your vacation short to answer my posting.

    Or if I was cruel, I could suggest that this demonstrates a very limited knowledge base, but I'm not that cruel.



    Ed, as Eric has pointed out we were talking about the STJ. Which you said "isn't even axial in closed chain". Why are you now talking about the TNJ?

    You are not serious with this statement surely? Amongst other things, we use instantaneous axes to enable us to better understand lower limb kinetics and to evaluate the effects that orthotic intervention has on these kinetics. How does my reference strengthen your argument when your argument is and I quote: "(the STJ) isn't even axial in closed chain" or better still from your DVD "the foot isn't axial in closed chain" ???????

    What my references did were to demonstrate to you that this approach to geometrical modelling of facets in order to identify motion at joints was not new, not your idea and not independent of axes as your statement above implied.

    Where does Craig, refer to you as a sagittal plane theorist? I don't recall a reference to your work in his past, present, future paper. I always thought Howard was responsible for the development of this theory? Anyway...

    Don't worry Ed, there is no strain on my part, frankly I enjoy it. Here's the interesting thing, in order for your contention regarding sagittal plane dominance to be correct (sagittal has two t's BTW) then the angle the axis forms to the sagittal plane should be dominant, that is if sagittal plane motion is dominant then the axis needs to make a bigger angle to the sagittal plane than to the frontal or transverse planes. If we look at the data from studies of STJ axial location:
    Manter, Root et al., Isman and Inman, Inman, Van Langalaan, Lundberg-

    If we take the average inclinations to the transverse plane and sagittal plane respectively, all of these previous workers show a greater average inclination to the transverse plane than the sagittal plane with the exception of Lundberg. However, none of the studies show an average inclination of the axis to the sagittal plane that is greater than the average to the frontal plane. In other words when we look at the averages there will always be more frontal plane motion than sagittal plane motion- So sagittal plane motion will always be less than frontal plane motion given these axial positions. Howver, if we look at the range of data reported in these studies, the Isman and Inman reports a rqange of deviation to the sagittal plane of 4-47 degrees and a range from the transverse plane of 20-68 degrees, assuming that the individual who displayed the deviation to the sagittal plane of 47 degrees had an axis inclined to the transverse plane of less than 47 degrees then this individual could show greatest movement at their STJ in the sagittal plane. However, and it is a big however, the majority of the data presented does not support your view and only by manipulating Isman and Inman's results somewhat can we make it support your view.
    But since you don't believe the STJ has an axis, this discussion is fruitless.


    So the only thing I'm straining with is this evenings bowel movement and where your notions are coming from because you offer no data to support your contentions and moreover, published data on the STJ axis seems to oppose your view of the world.

    Manter (1941) identified approximately 1.5mm of translation for every 10 degrees of STJ motion; the STJ everts betweem 4-6 degrees from heel strike during the 1st half of stance so, translation at this point is probably about 0.75mm. How much translation is necessary to create the effect you describe? And how do you know this? Interestingly, van Langelaan (1983) reported that positive translation occurred in half of his subjects and negative translation occurred in the other half. How does this positive and negative translation fit with your ideas?


    I don't believe I've ever said that evolution of the foot is occuring at the same rate as changes in surface terrain, but while we're here again, show me the evidence that terrain is a primary causative factor of overuse injuries of the foot and ankle and show me the evidence that the foot is not evolved to cope with modern terrain; while your there prove to me that the world is flat and hard, and show me that impact forces acting on the foot encased in modern athletic footwear are considerably greater than those acting on the barefoot impacting on bush and scrub-land; and prove the foot is no longer evolving. You can join in too David.


    Ed you said that the foot "isn't axial in closed chain" so how is this in direct agreement with your work? If you read the paper rather than just looking at the pictures you'd realise that we are not mapping axial position on the bottom of ANY foot, rather we track the 3D spatial location of the axis during the gait cycle, so were getting the position of the whole bundle in time and space. Why would you want a device to track an axis that doesn't exist in your world?




    Interested in your methodology here; how did you measure the facet angulation? What was the mean and 95% CI's for the posterior, middle and anterior facets? If the space is without function why do some people have one and others not?

    Can you explain what you mean by force is transduced? I've not come across this expression before, is it an engineering term?
     
  13.  
  14. David Smith

    David Smith Well-Known Member

    Dear Ed

    I have tried to get a copy of your DVD but it can't be sent to the UK yet.
    However I would summize that your orthoses are designed to reduce pronation velocity and RoM. They achieve this by increasing the stiffness of the medial arch with the addition of an orthosis that is cast to the shape of the foot in midstance and maximally supinated. They do not include a medial rearfoot post or wedge instead the heel cup is round in contact with the shoe.

    Here are a few questions that spring to mind.

    Is the foot cast weight bearing or semi w/b or non w/b.

    If the calc and heel pad make a ball and socket effect are you not increasing this effect by not posting.

    Do you believe that without posting there are no supinatory moments applied to the rearfoot by the heel cup.

    Is it correct that the stiffness of the orthosis is matched to the force time curve produced in each individual patient so as the arch is lowered in a controled fashion.

    Is a heel cup necessary in your design, could you just as effectively use a functionally dynamic (springy) arch support.

    Does this functionality extend to the lateral arch.

    Do you have any theory of the dynamic relationship between the medial and lateral arch.



    Cheers Dave Smith
     
  15. Dave follow the link, you can get the DVD content online- click on the right hand side of screen- somewhere- sorry can't be more precise.
    http://www.solesupports.com/index.htm
     
  16. David Smith

    David Smith Well-Known Member

    Simon

    Tried that but nothing seemed to happen and if it did I only have Dial up.
    Keep meaning to update.

    Cheers Dave
     
  17. EdGlaser

    EdGlaser Active Member

    Dear All,
    I have to slow this discussion down a little because there are five (Kevin, Dave, Simon, Phil and Eric) to answer against one (me). This seems a bit unfair to me...you need at least five more on your side to make it equal. LOL. So I will take one critique at a time. I understand why this strikes a nerve. It invalidates a huge body of work that many have built their careers on.
    Remember besides this fun... I also have to teach, research, travel, and run a rapidly growing company so I appologize in advance if it takes me a while to get to your criticism. Five against one does not make you right....just more prolific which means it takes more time to answer....Since many of your arguments are redundant I will try to answer them once and refer you to the DVD where applicable.

    Ed
     
  18. EdGlaser

    EdGlaser Active Member

    This is the most intelligent statement I have heard yet. It is great to have academic volleyball but ultimately David…you hit the nail on the head. You can see through the game and get to the point. Well done! By the way…Tautological is not in my vocab., thanks for explaining it.


    I never have been in academia, I have resided my entire career in the real world of clinical practice. My product was born out of clinical testing that I performed…not with the intent of publication, but to help my patients. Not everyone is you. Most Podiatrist are me. Nothing wrong with hard research…..I now fund it..…Research will follow after the inventor has theorized, created, prototyped, modified, tested, remodified, re-experimented, tested, evaluated and finally put in the field. The whole time learning, researching, changing and improving the product as results get better and better.


    That’s the heel CUP of the orthotic. You bring up two of the four reasons rearfoot posting is silly.

    What? Are you saying that he is studying the rotation of the calcaneus in the transverse plane or are you referring to a medial / lateral slide or maybe a/p translation. What I am talking about is calcaneal inversion and eversion of the heel within the heel cup. There is a great 3D animation of this in the DVD.

    You miss the point here. The principles I propose are so simple that no proof is required. Must I prove that heels are rounded on their plantar surface in the frontal plane. I think most people can see that. Must I prove that the heel cup of most orthoses is round. Now add the sock…yet another variable. Certainly you would never design a device to control a round object by placing it in a round cup. The heel can simply land on the cup in a fairly large (compared to the magnitude of your post) range of positions. Sure it is influenced to varying degrees by the shoe. Simple Geometry.

    Yes I am saying that the errors of you measurements do dwarf you actual post. Let’s see. The soft tissue under the heel can move 7-10 degrees in both directions (inversion and eversion)…. Don’t believe me…. Take off your sock and try it….. try it on the first ten patients or people you see. We did… to 50 people and measured it… it came out to 7-10 degrees in both directions depending generally on BMI (how fat they were). Then there is a 3 degree error in your goniometer and up to a 15 degree error in forefoot to rearfoot relationships in the cast. Lets see we’re up to +/- 28 degrees. So most Podiatrists are forced to take a WAG (wild a— guess) by putting most everyone in a 4 degree post. It’s unsettling.

    Bravo… Now that’s a good point. There is a variable in the co-efficient of static friction (CSF) depending on the sock material, topcover material of the orthoses, presence of moisture etc. The best topcover material I have found for this has by feel the approximate CSF of leather but is more consistent in thickness, hypoallergenic, wears like iron and glues well, and has a luxurious presentation and feel (important to the clinical practitioner)…. Ultrasuede. This is my personal preference of course. Many labs use cheaper vinyls (about 1/16th the price) which have a tendency to grab the sock when wet and slide freely when dry or powdered. Therefore, no general conclusions can be drawn except the heel will hit the orthotic in a variable positon depending on shoe and the heel will reposition itself over the orthoses to a varying degree. Neither bodes well for posting.

    True… and our theory deals with all of those forces however one cannot ignore the moment arm length when assessing torque. We talk about momentum down the leg in the DVD and frictional forces on the ground. The moment arm is defined however as the perpendicular distance from the line of force to the axis of motion. Yes it moves, but at heel strike, it is very very close. When exactly are you proposing the heel post works…..at toe off.

    I agree….what I am suggesting is that the axis of the STJ moves in open chain, swing phase supination, (By the way this would be an excellent thing to test with Kevin and Simon’s STJ axis locator…..how about it Simon) At the point of heel contact, and I think it was one of Kevin’s articles that showed this…. The axis does exit the plantar posterior lateral calcaneus in very close to where one contacts the ground. Shoe wear also can help confirm this. It would be neat to use the axis locator…. I’ll have to look at its design a little closer….and a patient walking over a lexan plate with a high speed camera underneath to see how close the axis is exactly to the point of heel contact. Gross observation will tell you it is quite close but it never hurts to get more exact.
    I forgot whether I agreed with you or disagreed…. Just giving you my thoughts.

    Certainly you are not divorcing internal stresses from positional changes, just because posts and skives could not achieve them. Yes the stresses applied by the tendons and ligaments at the end of ROM will cause deformity….re-position is a far better strategy than just blocking the last little bit of pronation with a post or more probably the arch of the orthotic. Sometimes when you make the post big enough…. It actually tilts the orthotic so far that the arch finally does touch the foot….in the end stages of pronation…. That would certainly cause the dampening effect.
    What you are saying here is that if we can prevent the joint from reaching the end of its ROM or do so less harshly….the foot will not deform. Great…. I guess with some posting we can certainly slow down the progression of deformity.

    Do you believe that “form follows function”? If we improve function through positional changes we accomplish so much more. We reverse deformity. You will have to look for yourself…. It would be a disservice to your patients to do otherwise.

    Please explain.

    Neither. We empirically through experimentation (and this is very proprietary) determined the average downward force using body weight and foot flexibility and then measure the upward force of the orthoses. We use Paschall’s law…forces inside an enclosed container are equivalent in all directions. We apply a force evenly over the entire surface of the orthotic while measuring both pressure and vertical translation of the peak of the orthosis every two thousandths of an inch. This creates a force curve on every orthotic. AS our experiments show, it turns out that the slope of the curve is indicative of flexibility of the shell. Then came a long period of data collection, putting dots on a graph like buckshot scatter. Eliminating the warranties we created a trendline that described a specific mathematical functional relationship between body weight, foot flexibility (and we developed a unique method of measuring that too (a grading scale currently used…. Something else new and then a new device now being tested at U. of Bridgeport in Conn. Called the Bors Flexometer, named after our own mad scientist). Of course new data is collected almost 400 times a day and the trendline continues to improve over time.
    Bore me…. I love engineering. I think it is the most fun part of my job. That’s why I love to talk to you. I understand that I am being chastised for not making my findings public earlier …. I am simply not such a big writer. I prefer direct communication like this.

    Very Respectfully,

    Ed

    PS: This is fantastic!!!! I can rarely find people as interested in foot biomechanics as I have found on this site.


    Simon, Kevin, Eric, Phil and Dave,

    With all due respect…. I submit this to the frontal plane community for consideration.

    Once there was a young man who's job it was to deliver water to this town. He carried buckets on a yoke over his shoulders. He knew how to get more water to the town. There were five year, double blind, randomized, controlled, statistically significant studies on the shape of the buckets and the handles etc. etc....Respected scientists made their careers publishing numerous articles showing that slight variations in the shape of the bucket yielded a significant increase. In fact, you could carry 2% more water if the bucket was shaped this way or that. Then along came a young inventor who proposed and built a pipeline. The public could easily see that he could fill swimming pools in the time that the bucket man could fill small washtubs. Still the scientists refused to believe that the pipeline was more efficient. Mired in the muck of articles and unwilling to deviate they continued to argue the merits of buckets.

    Open your mind here….can you see how this repositional sagital plane theory meshes beautifully with “supination resistance”.

    Edison made the first practical light bulb (although 24 previous attempts had limited success). Firstly, he did it because he had so improved the generator as to make delivery of electricity to every home possible. He owned the electric company. He wanted to invent something that would entice every home owner to want electricity wired to their home. So he invented the light bulb....to sell electricity. It is no less an invention and he is no less an inventor (in fact the greatest inventor in history with 1097 patents). He never published a five year, double blind, randomized, controlled study on whether the light bulb was emitting light....because anyone (except the blind) in their right mind could easily SEE light. Naturally you do not use light bulbs because you refer back to the studies on slight improvements in the candle or coal oil lamps.

    The changes in the gait cycle from Sole Supports are blaringly obvious.... they can be seen from satellite photographs (don't take that literally). Parents go to tears watching the dramatic changes in their children's gait cycles, deformities reverse, symptoms disappear (just as they would with Rootian or prefabs) but much more importantly....FUNCTON VISIBLY IMPROVES.

    I know what you are thinking..... GREAT...We've got him now. We can go into our standard tirade about the value of controlled studies, publication etc.
    No need... I know this. We are currently working with six universities on just such research. We also are doing far more research in house. I cannot share our results with you because of the rules of publication...your rules and because some of the data is proprietary. A great scientist would look at my discoveries as a research opportunity; one that I would be more than willing to fund (within reason) with NO STRINGS ATTACHED as long as the design of the study is fair and objective.


    Here is the problem. We are learning so much at such a rapid rate that the product is changing for the better all the time. In a five year double blind study....by the time the study is peer reviewed and published (another two years) the product that was tested is not the product we are using. What has driven the enormous advancements in electronics and computing....commercial interest. Yes there are certainly snake oil products that will not survive the scrutiny of science. There are also great discoveries that are ignored by science because of lack of scientific studies and turn out to be correct....like the Heimlich Maneuver, or Lorenzo's Oil.

    In this case, I made changes in the foot orthotic .... which I fabricated in my garage, that dramatically improved outcomes. By outcomes, I am not just talking about pain relief (your barnyard prefab does that) but changes in the gait cycle. I saw amazing results....like seeing the light emit from a bulb. I didn't think to invalidate my blaringly obvious visible changes because they disagreed with the accepted well published and documented norm. I did indeed desire to learn more, help make people better, create jobs in my community and also someday it would be nice if I did make some money off of my discoveries (heaven forbid, that would be a crime punishable by invalidating my entire contribution to the science of foot orthoses).

    You are correct that tissue stresses cause deformities. Where do these stresses come from? Muscle contraction, GRF, and reaching the end of ROM of ligaments and tendons. How can we divorce tissue stress from position when position changes all of the above. Not the miniscule, lame changes in position that rootian orthoses (with post and skives) make....even if we can look so closely at them that they appear significant. I am talking about a radical, dramatic change in position.

    Interesting....at the Western Congress I asked at the end of my lecture.... Are these ideas new? Unanimous agreement ....Revolutionary!!!!

    Thank you for all of the multitude of references you have provided to add to my lectures.

    Thank you,
    Ed
     
  19. EdGlaser

    EdGlaser Active Member

    Reply to Eric Fuller's first response

    Dear Eric,

    Great to hear from you.

    Incorrect… the COP is not a stable entity. It moves medially and laterally as you lean this way or that. It is only true for one instant. Additionally it will be dramatically displaced medially or laterally depending on calcaneal inversion and eversion which is the freedom allowed by the geometric shapes of both the two surfaces.

    Internal stresses that pull structures out of alignment and cause deformity are not vertical joint compressive forces but the pull of soft tissues when a joint reaches the end of its ROM as many joints will at the terminal stages of pronation (that is why pronation terminates….due to tissue stresses). Rootian orthosis with wedges allow the foot to almost completely pronate….it doesn’t take a genius to see that. Positional changes have been largely ignored because standard orthosis did nothing to create them and researchers were desperately trying to validate what they already had or make very minor variations on a theme (medial heel skive) instead of inventing something new. By the way Eric, you should see what we have done since you visited. Our calibration system has taken several giant leaps forward. We have added “calibration reference points”, an entirely new calibration device with a linear digital encoder that creates a force curve on every orthotic and then newest device (that I showed Dr. Payne when he visited) is being tested with a nine pin system that simultaneously delivers nine separate force curves and gives us considerably more data about change in curvature.

    Positional measurement is very poor but our casting technique is 67% (unpublished data) more repeatable than plaster. Capturing the MASS position in foam which is fast, accurate, clean, repeatable, closed chain, dynamic and most of all puts the foot in the correct (NOT NEUTRAL) position. You are right ….infinitesimal changes in position caused by Rootian orthosis with wedges does not make a significant change in moments but dramatic repositioning of the foot that is accomplished with Sole Supports does. In fact, by far the best way to influence the moments of the foot would be to re-position them.



    Incorrect….Time is extremely important….That’s why we have air bags. Impact or Impuse is the deceleration as a function of time. The more time you have, the less force is needed to accomplish a certain amount of work. Its common sense and Newtonian Physics. You don’t have the length of time it takes to step. You have the time between the instant of heel contact and the point at which the talar head disarticulates from the anterior facet of the STJ. The only way time can be “created” is by creating what we call in physics a dampening effect. By re-positioning the foot into greater supination, the foot is forced to go through every stage of pronation which in essence creates a time delay. The deforming stress that the anatomical structures endure is at or near the end of STJ ROM in the direction of pronation which is exactly where Rootian orthosis place the foot.



    Ok let’s do the math…. At 2.54cm/in (trying to make this easily understandable to an American Podiatrist)…1mm = .0393 inches = .00328 ft. A 150 lbs. person heel strikes on concrete barefoot with 3x body weight (but with a shoe on measurements of closer to 1.25x body weight are measured) but for arguments sake lets go the full 3x as if the orthotic is worn without a shoe…..so we’ll consider the force at 450 lbs. 450lbs x .00328 = 1.476ftlbs of torque without the shoe and 0.615ftlbs of torque with the shoe. I think that I am typing with more pressure than that. And these are impact forces. Once the heel pad compresses and soft tissue deceleration is complete the f scan will show a considerable drop in pressure. Now lets add time. Do a simple experiment. Take off your watch and put it on the table. Use a light force to move the watch. Apply that same force for and instant (say .1 sec) and see how far it moves. Now apply the same force for 1 second and see how far it moves. Whoa…it moves 10x farther. You just did more work by applying the same force over a longer time. Is this so hard to understand?


    The wear occurs evenly over the surface of the orthotic because the full contact in the MASS position of a Sole Support (which is unique (or “new”) in this respect). This question answers itself. By applying force evenly over the plantar surface of the foot (which of course varies some as the wave of force passes over the orthotic), the Sole Support pushes upward on the entire medial longitudinal arch. What is surprising is the little force that is necessary because unlike any other orthotic it “prepares” the foot for heel contact by carrying the supination at toe off through the swing phase which causes the patient to heel strike in greater supination. This levels the anterior facet of the STJ (another “new” concept) which creates a dampening effect or time delay in pronation. The delay is as or possibly more important as these COP moments. Over time, walking more ideally causes changes (plastic and elastic deformation) in the tendons and ligaments as well as learned or habitual gait patterns which also contribute to the reversal of deformity.

    What I am saying is that the reason no other lab had ever tried to be so aggressive with their product is because they did not do their physics homework. Attempts at going full height in the arch failed because there is a narrow range of tolerable force that is still adequate to control the excessive pronation of the foot. ONLY Sole Supports are calibrated to deliver the correct force to control the foot while still being tolerable. Labs “cast correct” orthotics to death…. Which makes their product NOT CUSTOM. They are not the shape of the foot…. But instead the shape of the arch fill. To do otherwise with polypropylene (which is neither malleable nor has the correct modulus of elasticity) would put most labs out of business with warrantees. You cannot change gait without applying a force. Most labs deliver orthosis that you can fit four fingers between the arch (especially when held in the corrected or MASS position) and the orthotic. They have to do this because of the ridiculous neutral suspension casting technique has NO FRAME OF REFERENCE and is therefore so variable as to make the cast almost useless. This is bad for three reasons:
    1. The foot drops 10-15,000x/day to a sudden stop.
    2. Efficient transfer of force between the foot and the orthotic is lost.
    3. By the time the foot pronates enough to hit the orthotic….the talar head has fallen off the anterior facet and body weight is coming over an unlocked foot.

    So even when you are able to mask symptoms….the best you will ever do is dampen the very end of pronation and slow down the progression of deformity…NOT reverse it or make people function signigicantly better. Dig with a teaspoon if you like.

    Spongebob and I are no strangers to self deprecating humor. I will answer your other rebuttal tomorrow.

    Respectfully,
    Ed
     
  20. EdGlaser

    EdGlaser Active Member

    Phil,
    Kevin did a good job of rebutting this argument. Just wanted to add that we saw the same thing in the Georgia State University Study. We were concerned that this degree of supination would cause lateral ankle sprains. What we found was surprising. Raising the MLA by pushing up on the arch caused a net medial displacement of pressure that acted to explain why we see a net reduction of ankle sprains (except in curve lasted or anti pronation or split lasted shoes or when combined with posts) the fact that the supinated foot is more stable overall (what PT's would call "closed packed") may also contribute.

    Ed
     
  21. EdGlaser

    EdGlaser Active Member

    Mr. Anecdotal looks in the mirror

    By "worked" you must mean relieved symptoms. Since prefabs do that as well as customs in this respect. (and there are pleanty of studies to quote here including the Pffefer study), we can either:
    1. Continue doing what most docs do...dispense "customs" that are no better than prefabs.
    2. Switch to Prefabs
    3. Shift you paradigm.

    How can you criticise me for reporting what I see and then give anecdotal evidence. Are you saying that you can actually believe what you SEE with your own two eyes clinically even without a paper. Maybe there's hope and I wont have to write a paper entitled "The Heel is Round". :)

    Thank you,
    Ed


     
  22. davidh

    davidh Podiatry Arena Veteran

    Simon,
    You said:
    "Don't worry David, I do this to everyone who I think is talking nonesense, it not just reserved for you and Ed."

    Phew! Thats OK then! :)

    You then said (much cut):
    "But remember David, it's where you publish them that is as important, you need to go for an index medicus linked, peer reviewed Journal, not something from the SMAE institute for example. "

    Yes, but if you know I've published in the SMAE Journal, you'll also know I've published in that well-known and respected ( :cool: ) Journal, the BJPM (now called Pod Now or some such), and The Foot, both of which are reviewed.

    Ed,
    I know what it's like to be ganged up on - believe me!
    I was really making the point that my 4-degree RF posted orthoses work, in spite of being 4 deg RF posted.

    Years ago (on Jiscmail) I pointed out that the RF post does little more than stabilise the arch support-part of the orthoses. Not that that may not help in some cases.
    Out of interest, I post pretty much all of the orthoses I prescribe FF only, and usually not more than 2 degrees. Seems to work well, and there is a ref which justifies to some extent why I do this (Cornwall and McPoil, Effect of RF Posts on reducing FF forces - JAPMA 92).

    Regards,
    davidh
     
  23. Ed:

    OK, Ed, I give up. Your grasp of physics, proper use of terminology and your familiarity with the foot and lower extremity biomechanics research and orthosis research over the past 50 years is so amazing that I have decided to just listen to you and not disagree so that I can "learn from the master" and grow intellectually by absorbing all of your new ideas. :rolleyes:

    Well..........at least for a week, while I'm lecturing at a Foot and Ankle Symposium in Beijing, China.
     
  24. Maybe reviewed, but not index medicus linked and therefore, pretty low on the rankings- sorry.
     
  25. Javier Pascual

    Javier Pascual Active Member

    Ed[/QUOTE]

    The changes in the gait cycle from Sole Supports are blaringly obvious.... they can be seen from satellite photographs (don't take that literally). Parents go to tears watching the dramatic changes in their children's gait cycles, deformities reverse, symptoms disappear (just as they would with Rootian or prefabs) but much more importantly....FUNCTON VISIBLY IMPROVES.


    Ed,

    I've been following the whole discussion and I've found it very interesting. Unfortunately, in Spain we did not have any podiatrist as Merton Root who stablished a core of knowledge on foot biomechanics. So as you can imagine, here we are plenty of theories. 3000 Spanish podiatrists means 2750 theories of foot function.

    I have heard the quote above hundreds and hundreds of times here in Spain. Unfortunately, none could never give me any consistent and reliable data that make their "Revolutionary" theories true. HOpefully I am wrong now and you have the data, but till the moment the only thing I have read is just a theory, no data, just a theory, and believe me, I have heard hundreds of theories.

    Looking fordward to seeing your data soon,

    Cheers
     
  26. David Smith

    David Smith Well-Known Member

    Dear Ed

    Havn't got much time this evening but I will reply to you in detail..

    I have no wish to berate you. I would like to explore your research some of which sounds quite interesting.
    However the manner in which you have chosen to introduce your product onto this forum has been naive at best and at worst arrogant.
    To burst onto the scene and declare that you are king of the hill and everyone else is talking crap is not going to endear you or get a sympathetic ear. Even if it were true, which is unlikely.
    When writing to a forum (this forum) it is necessary to write concisely and accurately as possible. Kevin Kirby taught me this several years ago.
    This is because people can only judge you and your ideas by the words that you write. Inflection, intonation, and inferrence are not easily communicated, especially when trying to express engineering theory. Perhaps you are trying to simplify the concepts for the sake of your audience but this is leaving you open to massive critisism.

    I am only a junior in comparison to many on this forum but I believe I do have a fair understanding of biomechanical engineering and, for me at least, some of your explanations and terminology are questionable. For instance do you really define the action of force as a flow, or is force instantaneous at any point in a system. (in terms of Newtonian mechanics). I talked about the flow of force once and got a deservedly severe barracking which involved Star Wars analogies. LARF! I nearly did :mad:
    Do you really believe that the heel is round and applying a wedge has negligble effect. Have you looked at an ink mat impression of the weight bearing foot. Have you ever stood on a small pebble and severely sprained your ankle, one's foot certainly does not rotate inside the shoe because of freeplay and lack of friction. No its the STJ that rotates until the resisting soft tissues produce enough force to cause trauma, which is somewhat more than the force it takes to press a typewriter key even if it was 1930.(the year, not half past seven)
    If you do believe this then, however good your orthoses are, the theory behind your product, in the terms which you have used to describe them, will not stand up to scrutiny by the rules of traditonal mechanics .

    I write this as a genuine attempt to help you. As I have said some of your research sounds interesting and it would be a shame to throw the baby out with the bath water just for the want of acceptable protocol.

    Take some time to consider your replies and then perhaps the force will turn in your favour.

    Cheers Dave
     
  27. EdGlaser

    EdGlaser Active Member

    Imagine a better approach

    Dear Kevin,

    I wanted to see what the orthotic lab with the legend of podiatric literature as a medical director and newsletter author was doing…. So I checked out the website of your lab. What I saw was a product that reflected what we were doing about ten years ago with weight ranges, only with the wrong materials. Where did these weight ranges come from. What data do you have? These ranges are wildly overlapping (example: 3/16 poly is 130-335 lbs.) Your calibration technology must be non-existent. (For example: I can’t seem to find any mention of your “calibration reference point”). Why are you varying the flexibility of the orthotic? What part of the orthotic is effected by this? The heel skive? I don’t think so. It’s the arch. The manufacturing company, not you of course, is has realized that it is the arch that should contact the foot and have the effect and not the post or skive.

    So what position do you cast in? Instead of leading the profession toward selecting a more scientific position to put the foot in…you seem to be defending neutral position.

    Dr Sanner, in his review of your book, said, “This is the first text published in more than 20 years to properly describe how to find the subtalar neutral reference position.”

    Interesting…. In your recent newsletter about the goals of biomechanics you extensively trounce “neutral” position as not being the goal of Podiatric Biomechanics but you never even allude to what IS the correct position to capture the foot in or how to capture that position correctly, accurately and in a manner that is repeatable. Does the cast really matter to you? If we are just trying to reduce tissue stresses, will any vaguely foot shaped device work as long as it has the proper wedge in it? That is…as long as it effectively moves the COP relative to the shadow of the STJ axis. In other words, would it not be simpler and cheaper for your customers to apply pre-fab wedges to pre-fab orthosis to reduce tissue stresses?

    Firstly I find it interesting that you even choose a “position” when you claim it is tissue stresses and not position that is important. You claim that position has nothing to do with the etiology of deformity. With the unreliability of neutral suspension casting and your certainty that position is not important, why do you cast at all? Why not just trace the foot on a piece of paper put the foot on a wedged platform? Shoe modification should be more effective than orthosis (they have a longer lever arm).

    There are some excellent pictures in the DVD showing a very flat footed person standing first on the ground with his heel everted and second on a 10 degree varus wedge with his heel everted even more….both in relaxed calcaneal stance position. Oh…I guess the more everted position is somehow alleviating tissues stresses.

    It is so interesting to see how different members of academia react when a new paradigm is proposed. Some consider its merit and want to test it, experiment with it, see if it does work …and Why? Can we take it further? Are they going in the right direction? (Craig, do you remember when I asked you that question during your recent visit?) Others get angry and defensive and try to strain to find anything about it to attack. It lets me know who is objective and who is merely trying to defend the status quo.

    I find all of the digs about my commercial interest very funny, although totally fictitious and without merit. (Go to the website for the Western Congress: http://www.thewestern.org/exhibitsponsor/index_html/Western 06 Exhibitor Prospectus.pdf page 8 where it lists the labs that buy booths: Funny…I see your lab but not Sole Supports, Inc.) To explain this to both you and Eric: The entire Odyssey that has brought Sole Supports, Inc. and the Bottom Block lecture to the prominence that it currently enjoys (60 booked lectures in advance) has been an interesting adventure. I count my success in business to be among one of my proudest achievements. The fact that I have successfully turned a garage operation, through education alone, into one of the top labs in the country without advertising is amazing and a credit to our technology, my theories, the many contributions of our clients constantly pushing the envelope, their clinical success on patients, the hard work and dedication of all of our employees (everyone from the President to the Janitor) all focused on ONE CORE VALUE: “WE MAKE PEOPLE BETTER”. No… we have not done it by making contributions to Podiatry Schools or owning their biomechanics departments … Except for research, we will NOT get in bed with a school financially. As far as our lab sponsoring my lectures….that is a varied history. When I started presenting my theories in 1992 I talked anywhere they would listen, to any audience. A year into my lecture career I started getting some honorariums. Then as my company grew I started donating back the honorariums to the state societies because I knew the reality of running a state organization (being the former Treasurer of the TPMA); that funds were critical and a large part came from their meetings. Now I find it easier to just sponsor my own lecture which is really the same thing as donating it back. I looked at it as an act of generosity….giving back to the profession. I think most state associations would not want to loose their lecture sponsorships on the basis that you think that all sponsored lectures must have commercial ties and therefore be bogus.

    At Sole Supports, Inc. there is a lot of new information to disseminate. So much so that we require all new customers to attend a certification course before being allowed to use our product. They must demonstrate proficiency. We don’t accept any cast we receive. Our first step, before a cast can even qualify to become a Sole Support mold, is a QC process. This way we can trust the cast and actually use it to determine the shape of the product. Only the most minor of changes are ever allowed if it is approved by our Technical Support team to allow rare cases to calibrate more accurately. If we just wanted to sell product we would put full color glossy ads in journals and magazines and accept any customer and any cast they send …. like most labs do. Using Sole Supports, Inc. is a privilege that the certified practitioner earns and enjoys through education and their ability is re-tested on every patient. Why do we put this hurdle in the way of people using our technology? Because we actually CARE what is called a Sole Support. This also controls runaway growth that can easily put one out of business or worse…compromise quality or service.

    In our hands, that is, when the arch of the orthoses actually does touch the foot, the shape and position are extremely important and a bad cast will make a bad orthotic. We use the CAST to determine the shape of the orthotic, not the arch filler. We use the “pen test” (something else new) to establish a frame of reference and to QC the casts. We of course can’t catch every imaginable casting error. The only way to do that would be to have every patient in front of us during the QC process ….but we take every reasonable precaution to insure the highest quality and accuracy of cast possible.

    I feel that your work is leading the profession down a dead end street. By setting your standards of what can be achieved so low that minor improvements in terminal velocity or “tissue stresses” seem like fabulous advances when they are not much more than standard Rootian biomechanics behind another mask….with bigger posts. Medial heel skive is a variation on a theme (hardly a new idea) and certainly not a paradigm shift.

    I applaud your attempt to introduce physics into foot biomechanics. Well done. You are straining however, to use it to try to prove that the old theories, with minor modification and rewording are still applicable. Good luck. You certainly have my blessing to pursue this avenue of thought.

    The difference between what happens in the research facility and what happens in the real world is striking. In the research lab you try to control and eliminate the influence of every variable except one. To do this you carefully select your research subjects to avoid possible academic criticism. The clinical practitioner does not have this luxury. In the real world, we don’t choose our subjects….they walk in our door. They don’t walk in straight lines….they hike the Muir Trail or mountain bike in Colorado. COP in relation to STJ axis have minimal effect there. This is a real world technology for real world practitioners that want to improve gait. Please understand that again, I am not discounting what we can learn from research, but my point is that the clinical world does not operate in a vacuum like a research lab.

    There are certainly those that just want to cover up symptoms, like a cortisone shot, and don’t care how the foot functions or to reverse deformity. That’s a well paved roadway that you are resurfacing with scientific papers. The end of that pathway is a place where prefabs = customs. This is a place most practitioners in private practice want to avoid. This is unfortunately the path that the industry is going. Cheapening the products, pressure plates and other “smoke and mirrors” create orthosis with beautiful idealized curvatures that are perfect mirror images of each other when the feet are neither. While you are blocking the end stage tissue stresses, we will be applying counter stresses that re-position the foot, applying forces over the entire surface of the orthotic-foot interface (not just the heel skive) and changing foot function in a significant and positive way. We believe that form follows function….maybe because we SEE it happen every day on real people.

    My lecture and my DVD are designed for the general Podiatrist in the US in private practice who is looking to effect greater changes with foot orthosis than Rootian orthotics or those with skives could produce. Biomechanics is a dry subject. My course makes it fun and interesting. It sparks an interest in the physics of foot function and proposes an entirely new theory. As you can see, this is not some simple little modification but a comprehensive technology involving new foot position, new method of casting, manufacturing technology, involving physics, embryology, and good clinical medicine.

    If the round heel cannot rotate within the round cup of the orthotic then how is it we see some patients pronate with obvious heel eversion and others supinate with obvious heel inversion within the same type of shoe? Are both motions not frontal plane rotations? Why is it that when we stand the same person on a Sole Support with a rounded heel cup, the heel is rectus while in a posted or skived orthosis they remain visibly everted? By the way this is easily seen when they are standing in our see through shoes.

    Several comments have been made as to what I read and know. Wild assumptions about my research, motives and knowledge abound. I don’t think I have submitted a list of my reading to anyone who has responded.

    What I have learned here is that this forum is not for the open exchange of new ideas and theories but instead is a place where a few ivory tower academians are quick to squash new thinking with baseless personal attacks in an apparent attempt to protect their research findings from criticism. My research will continue regardless of how many articles I do or don’t publish or read because I want to make a difference in the way my patients walk and reverse deformity.

    Thank you,
    Ed
     
  28. EdGlaser

    EdGlaser Active Member


    Dear David,

    Of all of the people who have responded to my theories you are one of the few who has approached this with both an open mind even when you are criticizing my approach. I like the tone of your comments. I suppose that I thought at the beginning that I could propose my approach and it would be considered for its merrit. Instead, I was put on the defensive immediately with personal attacks for daring to even consider deviating from the current dogma.

    I think that posts and skives do have limited value to block the terminal velocity and range of pronation when the arch has been cast corrected to the point where it is ineffective in re-positioning the foot. It is not appropriate with our technology. We tried it early on and found posts and skives to make our product intolerable.

    I don't see why no one can even imagine that re-positioning of the foot in maximal midstance supination will have a far more dramatic effect on foot function than dampening the terminal pronation.

    I thank Dr. Craig Payne for creating this forum because it has sparked an international interest in my work. Research is currently going on in several universities on our technology. Data will be forthcomming.

    I do not mean to seem arogant. We have so much more work to be done. On some things I may be wrong. That is OK. Ultimately, I feel that I have made a major contribution to the science of foot orthotics that takes it in a direction that would be roadblocked totally by current frontal plane theorists. Sometimes I have to push pretty hard to move minds stuck in the inertia current thinking.

    The bottom line is that we are talking about a foot orthotic here...not a heart transplant. If Kevin and Simon can relieve symptoms better than Dr. Scholl or Superfeet with more agressive posting and low arches, no one is harmed. Patients feel better. I personally want more. I want a theory and technology that blows pre-fabs out of the water so that the patients experience changes in gait cycle that are powerful. In America, third party reimbursement for foot orthotics is drying up because well controlled scientific studies show that prefabs equal or sometimes beat what Podiatrist are prescribing as "custom". There should be no contest. If a patient is going to pay hundreds of dollars for a "custom" it should be unquestionably superior to anything they can get off the shelf at the drug store. We need a major paradigm shift if custom foot orthotics are to remain a part of podiatric practice. We need something we can point to that clearly shows that custom foot orthotics mean something. We can't point at symptom relief...pre-fabs do pretty darn good in that respect. What else is there that we can hang our hat on......function.

    Thank you for talking to me like a person. I will heed your advice.

    Ed :)
     
  29. Ed:

    I wish you luck in your endeavors to attempt to help people with better orthoses. I believe we are alike in this respect. However, your constant paranoia, where you think that a few of us are trying to "squash new thinking with baseless personal attacks", really amazes me since I feel we are making very valid, mechanically sound arguments to your ambiguous and confusing theories and your claims that your orthosis product is better than any that has ever been produced in the world.

    I'm sure that as long as you pay seminar organizers around the States so that you can hold seminars to promote your ideas and your company, you will have many that are very willing to have you speak at their seminars (even though you may only have 6 people in the audience as you did at the Western Podiatry Congress). However, until you get some of your research or theories published in a peer-reviewed journal or get invited to speak at a major podiatric seminar by the seminar organizing committee, unfortunately, you will be considered to be just another one of the many podiatrists that thinks their ideas are the best in the world and that anyone that challenges them with logical and reasonable objections to their ideas must be "out to get them".

    The bottom line is, Ed, you would have been better off spending more time in the library reading the research that you obviously haven't taken the time to digest rather than playing around in your garage for 15 years.
     
  30. Javier:

    Good to see you finally start to contribute to Podiatry Arena. Please give my regards to Angel, Ana and Juan and the others in Madrid. Looking forward to more comments from you in these forums. Hope the research project is going well.
     
  31. davidh

    davidh Podiatry Arena Veteran

    Simon,
    You said:
    "Maybe reviewed, but not index medicus linked and therefore, pretty low on the rankings- sorry."

    Don't be, you are quite correct. What I was doing was pointing out that at least I had published in reviewed Journals, as well as the BChPA Journal.
    Regards,
    davidh
     
  32. David Smith

    David Smith Well-Known Member

    Ed

    In reply to your post of 21st June 2006 02:42 AM

    Because of time restraints I'll have to answer your replies in parts in between customers.

    Transverse motion, here is a typical example of inconcise writing, it was obvious to me I meant X axis transverse plane rotation, but not to the reader.

    Interface Friction
    The frictional forces within the interfaces of the shoe and foot are many and varied. I would assume that the one to consider would be the interface with the lowest coefficient of friction. Have you looked at this area and do you have any CSF CKF(coefficient of kinetic friction) values.
    Coefficient of static friction (Us) equals the ratio of the force between the surfaces of interest (Fn), eg leather and wool, and the applied force (Fs) required to overcome the force of friction between the two and translation begin.
    Formula static = Fs= Us x Fn or Fs-(Us x Fn) = 0. Kinetic = Fk- (Uk x Fn)=0
    Uk is variable but rule of thumb is Uk = 0.5Us so (Us/2 x Fn) - Fk = 0

    So it wouldn't be very difficult to do some experiments find the CSF of common materials used in the shoe foot interfaces. Just drag some cotton, with a 1kg weight on top, over a piece of leather. Measure the force required
    Divide Fk by Fn multiply by 2 and thats your CSF.

    But is this necessary? When we measure the force applied to the foot by GRF
    the value will represent the opposite force applied to the ground and we do not need to consider interface variables. By simultaneously measuring the RoM of the calc it is a simple matter to find the moments about the joint of interest ie STJ. (well simple in principle).
    Typical peak semi normalised Moments about the STJ Xaxis (transverse plane)might be 0.1(N/m)/(kg) (global axis) at 20% of stance phase.

    If we examine the force / moments curve from 0 - 20% with a sample rate of 120Hz there is no indication of a sudden change in linearity which may characterise the reduction in applied force when Fs overcomes the CSF and becomes Fk, which as shown earlier is Fs/2 therfore there should be a corresponding dip in the force / moments curve. I have never noticed this.
    There are some changes in the force curve which only last 1 sample 1/120th sec. I would think that positional changes of the heel would take much longer.
    Perhaps a higher sampling rate is required. This unlikely since at 120Hz the narrow peak force curve or heel claw back seen in many subjects gait is clearly charaterised and only last 20ms (2% total stance phase of 0.8 - 1sec) typicaly. Heel claw back is seen in some subjects as the heel contacts the ground and is in the opposite direction to the CoM progession as the leg swings slightly backwards at the end of swing phase.
    Perhaps the reason for this is that the lowest CSF is greater than 1.2 which would be close to the highest Fs force available to apply to the interface. The CSF could be much lower if the Fs was not applied parallel to the surfaces, which seems quite likely.

    More later Cheers Dave
     
    Last edited: Jun 22, 2006
  33. EdGlaser

    EdGlaser Active Member

    Outstanding

    David,

    Now this is fantastic. I am not sure that I totally understand everything you wrote, but that's OK. That's why I have engineers and a physicist. We will have a round table discussion about this and get back to you soon.

    Just a quick question. Do you think that the actual motion has to occur during peak force loading? Can changes occur at toe off that are carried through the swing phase? or in swing if the orthotic is high enough medially?

    As you point out, CSF is a function of the angle at which the force is applied. Outside of the lab is every step the same? How does controlled lab gait differ in this respect from walking across the grass or hiking an uneven trail or sidewalk? The changes I speak of may not occur in a single step but are variations between steps. In other words, I am saying that there is a variable here to consider only because the orthotic is not glued or nailed to the calcaneus. What do you think?

    Respectfully,

    Ed
     
  34. EdGlaser

    EdGlaser Active Member

    Dear Kevin,

    I have answered substance with substance. This dribble I’d rather ignore. Its funny, I went back and looked at your responses:
    #14 No substance….just personal attacks
    #24 No substance….just personal attacks
    #42 No substance….just attacking the DVD and patting yourself on the back
    #63 No substance …just sarcasm
    #69 No substance….back to personal attacks

    Lets try to have a more civil dialogue, without all the attitude. For starters, please answer the questions I posed in #67 in paragraphs 1,4 and 5.

    I think I explained more about my honorariums already than you need to know.

    There were eight at mine. Jeff Root had five. I asked to speak to the general sessions but I was told that Paul Scheerer ran that and there was no way. I thought I did really good considering that Paul scheduled the PICA risk management seminar at the same time slot and many podiatrist needed this course to get a considerable reduction in their malpractice insurance premium. These were eight guys that really wanted to learn biomechanics and they walked away feeling like they learned more in four hours about how the foot works, than they learned in four years at Podiatry school. I think because biomechanics in Podiatry School is ambiguous and confusing, to coin a phrase. It can be summed up in these words: Cast them in Neutral and make an orthotic with a 4 degree rearfoot post.

    Wrong again…How do you manage to pack so much misinformation in such a small space.
    In just the last 10 yrs. I have lectured at:
    • 53 Podiatric Medical State Societies including regionals and the APMA national
    • 52 State societies in PT, DC, ATc, O&P, OPA
    • 31 lectures at 23 different Universities
    • 52 lectures with seminar companies (I work a different deal with each company depending on what they deliver to me, some have paid me up to 2K/day to speak plus travel and others ask me for money…in either case, I evaluate the value and exchange accordingly)
    • Additionally, I have delivered over many, many lectures that we sponsored or were commissioned by large companies such as Hanger, numerous hospitals, large PT companies etc., etc., etc..

    The trouble is that none of this has to do with posts and skives…so why are you so obsessed with discrediting me with misinformation.

    Bottom line Kevin, get your facts straight, and spend more time thinking outside the box instead of reinforcing its walls.
    Ed
     
  35. Ben

    Ben Member

    As a very young Podiatrist and also somebody being exposed to the engineering principles of biomechanics from a relatively naive background I have found this thread extremely interesting and something that I have followed... but maybe not totally understood all concepts.

    From an objective point of view there appears to be a few different agendas occuring here though.

    Firstly I think that somebody who is willing to challenge previously taught paradigms is essential to the progression of the profession, but those that are debating seem to be doing a very good job of this on all accounts, and backing this up with published work... and most importantly on a regular basis.

    Ed it certainly sounds as though your very comfortable with your 'new' theories, but to somebody who certainly does not have to qualifications of many that have contributed, it also sounds very much like a sell, and a contradiction in many areas. I think the one most clear to me is that you claim to be doing research to change the podiatric biomechanical world, but also stating that at the base of it all your a clinician and your going to do what works. Much like the posts that said the root orthoses has fixed their foot problems.

    Certainly this is no criticism to any of above that have posted, but there also seems to be a US dominated debate with people who obviously know each other relatively well. Again the young and naive side of me comes to the fore, I am still trying to establish myself as a Podiatrist, but I would love to hear from some other researchers who can take an objective look at this and who may have been quiet on issues presented so far. I would also like to hear some posts from Podiatrists using the Sole Support orthoses, and those that may have tried them and not liked them.

    Regards to all... I think this arena is a great learning environment and definitely contributes to the profession.

    Respectfully,
    Ben
     
  36. David Smith

    David Smith Well-Known Member

    Ed
    Quote
    "Do you think that the actual motion has to occur during peak force loading? Can changes occur at toe off that are carried through the swing phase? or in swing if the orthotic is high enough medially?"

    Don't know if I can answer this reliably since I have never done or read any research to find out. Most of my research (only a small portfolio) has focused on the stance phase of gait. We alway evaluate our output data in terms of is this data accurate, reliable and useful and in what context are these parameters applied. In this way one soon fully appreciates the caution that should be used when making assumptions and using intuition.
    It may be possible that relative positioning of the interfaces may change through out the gait cycle but on relatively flat surface in normal gait it is unlikely. Over rough terrain there are so many variables that it would be impossible to extrapolate.
    Most of my customers are not sporting types and the great majority who present with severe foot pain are women who work in shops, pubs, factories and are standing or walking short distances all day. (this may be because that is what most women do) The exception to this are male golfers with plantar faciitis. Both demographics, in general have good results. A 1 year audit followed by a questionaire gave results which can be summarised as 80% relief for 80% of customers. Not bad but that was a few years ago. I think I have improved since then. This all empirical and I'm not sure what scientific conclusions, if any, can be drawn from such observations.
    I am sure that calibrating the stiffness of the arch support element of an orthosis is useful. But my main concern about the Sole Support product is that it appears to be a single solution intervention.
    Anyway I get back to your other replies from the 21st.june.

    Cheers dave Smith
     
  37. David Smith

    David Smith Well-Known Member

    Ben

    I am a UK resident and so is Simon Spooner so is Phil Wells and David Holland,
    Kevin Kirby and Eric Fuller are U.S. (but definentely not u/s) Javier is Spanish
    Craig Payne is Australian. (I'm not sure about Ed)
    John Kettley is a weatherman a weatherman a weatherman, John Kettley is a weatherman and so is Micheal Fish, and soOOO iiiiis Ian MacKascille, AND SO IS WINCY WILLIS!

    Quite International I would say, plus a nice little ditty for your money.
    So write your cheque on the back of your name and address and sent it to me at the looney bin.

    Cheers Dave Smith (with a little light relief)
     
  38. David Smith

    David Smith Well-Known Member

    Ed

    "True… and our theory deals with all of those forces however one cannot ignore the moment arm length when assessing torque. We talk about momentum down the leg in the DVD and frictional forces on the ground. The moment arm is defined however as the perpendicular distance from the line of force to the axis of motion. Yes it moves, but at heel strike, it is very very close. When exactly are you proposing the heel post works…..at toe off."

    I am definentely not ignoring levers. I am bit confused. Can you define in terms of axis, global or local, by whichever convention you usually use, the 3D vector or the three uniaxial force vectors of the applied force/forces at heel strike and the position it is/they are applied.

    You appear to be proposing three contradictory premise.

    Q
    1) There are translatory forces which may cause the heel to slide in the shoe.
    2) There are negligible lever arms so that applied forces can cause negligible moments about the STJ at heel strike.
    3) There are large moments about the STJ that can only be controlled by a large intervention force applied in the correct way IE a calibrated arch support.

    A
    1) If there are translatory forces then because of the geometry of the rearfoot anatomy it is impossible to have caused no moments.

    2) appears to contradict 3)

    Are you saying there are large plantarflexion moments and only small pronation momemts. This would imply that it only requires a small force to reduce pronation moments, a small force applied by a wedge, (realise that I am referring to moments in one direction as by my convention all moments and forces add up to Zero -or- Equilibrium) .
    I realise that the calc must pronate to plantarflex so if you inhibit plantarflexion then you also inhibit pronation but that's why we use TRIplanar wedging deep heel cups, increased calc angle fascia and cuboid posts Plus varying type of material or thickness to control rigidity. (just refering to rearfoot)
    In this way we can customise the orthosis for each customer. A properly calibrated medial arch element may be a useful addition but not an entire treatment regime on its own.

    BTW I have found typical peak X axis moments are 0.1(N/m)/(kg), Y axis 0.3(N/m)/(kg) and Z axis 0.3(N/m)/(kg) global axis system. right hand rule, Y=vertical direction, X = P-A direction, Z = M-L.

    More Soon Dave
     
  39. Try this experiment. Take a forefoot striking runner, add heel lifts. Sometimes, not always, but sometimes they will start to heel strike during running- I think the sagittal plane theory provides the rationale for this observation, with the orthotic effect on the weightbearing contra-lateral limb influencing the swing limb.
     
  40. efuller

    efuller MVP

    I know the COP is not a stable entity, it does not have to be for my argument. My argument was that a wedge changes the moment from ground reaction force by shifting it to a different position from where it was. To know why the foot moves where it moves and to know why it moves as fast as it does, you have to know the moments applied to the bones. The location of the center of pressure relative to the STJ axis determines the moment from ground reaction force. If the moment from ground reaction force is reduced then the foot's internal forces will not have to be as high to resist this moment.

    Wearing the device you made for me reinforced my belief that muscular activity adds to the net moment in the foot and that some of the resupination seen with high arched devices is from muscular activity. I tried to wear the devices for a week and by 6th day I was waking up in the middle of the night with pain in my arch and my posterior tibial muscle was sore and I had pain in my PT tendon. It was partially relieved by adding a moleskin medial wedge, but they did not make feel better than the devices that I already had.


    You have to use moments to reposition the foot. What is the source of those moments when a patient wears your orthosis?

    I disagree with the notion that "dramatically" more supinated is always better. Say, in a particular foot with sinus tarsi pain, there is a pronation moment from ground reaction force. The theory is that this pain is caused by a supination moment from the floor of the sinus tarsi that is needed to oppose the pronation moment from the ground to bring the net moment to zero when the foot is at rest. When a varus wedge under the heel shifts the center of
    pressure more medial there will be a smaller pronation moment from the ground and hence a smaller supination moment from the floor of the sinus tarsi is needed. Once the moment is reduced to the point where there is no pain in the sinus tarsi, and the foot is still at the end of range of motion, what is the advantage of adding additional supination moment? The foot does not hurt and the patient is better.

    My original contention was that time was irrelevent to the arguemt at hand. Your analysis applies to impact, but not necessarily to internal stresses. In the sinus tarsi example above the pain is not necessarily caused by peak impact, it is caused by peak moment about the STJ. The shift in center of pressure will reduce the peak moment at the STJ and hence the peak force on the anatomical structures that are responsible for the pain. Would you agree that a smaller force is better than a larger force, no matter how long it is applied?



    Ed, I don't know how to put this nicely. Your mechanical analysis is off. Foot lbs is torque not pressure. You also are talking about impulse. I am talking about moments and the resistance to moments. Would you explain to me what is wrong with looking at moments. My argument for moments is above.


    So the device works non weight bearing?? I could see how the muscles, which are being used more could hold the foot more supinated in swing. Is this what you are saying?

    What is a force wave?

    How do you determine the ideal gait?

    Ed,

    You wonder why everyone is ganging up on you. The dig with the teaspoon quote is a prime reason. Yes, you are asking us to question our beliefs, but you have to explain why your way is better. You have tried to explain why your way is better by answering a moment question with an impulse answer. There is published literature that says that moments at the STJ and other joints are altered by wedges. That is why we are asking for data and studies to back up the claim that wedges don't do anything. Even without the studies, I would like a theoretical explanation as to how your device "puts" the foot into a more supinated position. We may be carrying buckets of water, but you have to at least explain why your pipeline works. Magical thinking only works if you are sellling stuff to the defense department and the other unquestioning.

    Regards,

    Eric
     
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