In his most recent Practice Perfect 547 article, Jarrod Shapiro, DPM reviews some recent literature supporting the case that some of the principles that Root established should be abandoned due to conflicting evidence that has been collected recently.  We're interested in your opinions. Review the eZine and feel free to dive in here.

  • Comments (5)
  • Daryl wrote:  “First we have to ask ourselves, “What is Root theory?”  Dr. Root put forward a whole concept of what made for the optimal foot function in all of the joints of the foot and also for trying to classify feet as to etiologies of abnormal function, and also for a change in the way that orthotics are molded and modified to try to promote a foot function that is closer to the ideal. So when one questions Root theory one really should say what exact Root principle they are talking about.”

    This is a really good question.  Because if you are going to critique, or defend, a theory you need to define what that theory is.   Is the theory that certain foot types cause you to walk a certain way?   Another question I have is how does the theory explain how orthotics work.   On Podiatry Arena, Mert Root’s son Jeff, posted a quote from Mert saying that a functional foot orthotic did not push the foot toward neutral position, it did not support a deformity and it was not an arch support.   That quote was in response to a Consumer Reports article being critical of the explanations of how orthotics worked.   Mert’s quote was interesting  for two reasons.  The first reason the quote is interesting is that really is the reason that a lot of people believe is the rationale for how orthotiocs work.   The second reason that quote is interesting is that he does not say how they do work.   You can’t criticize Root theory if there is no theory.   I recently re read Eric Lee’s 2001 Clinics in Podiatry review of the history of Root theory.   Eric Lee corresponded extensively with Mert.  As you read the  rationale behind the changes that were made to functional foot orthotics over time it is interesting to note the vast majority of the changes were made, not because of some adherence to a theory, but because what was done worked in actual practice.     So, all  Root supporters out there, answer this question.  Why is an orthotic made from a neutral  suspension cast better, than an orthotic made from a semiweight bearing cast.   And, if your answer includes arch support, support a deformity, or move the foot closer to neutral position, do you think Mert was wrong when he made that statement saying what a functional foot orthotic does not do?

     

    Daryl wrote:

    “As I have analyzed the pre-Root literature, I find that most of the Root concepts were already in the literature.  There is only one concept that I can’t find pre-dated Root and that is what I have come to call “The Root Postulate.”  This is the concept that the midtarsal joint is in its optimal position when it is fully pronated around all its axes.  As a result, Root modified the casting of feet from a semiweightbearing state to a nonweightbearing state so that the shape of the plantar foot could be captured with the midtarsal joint in its maximally pronated state.  …..  Some cut…...So has Jarvis, et al. disproved The Root Postulate?  I find nothing in the paper to question that postulate.  Before one puts Root in the trash bin, we need to first disprove this - what I consider the most important of all the Root concepts.”

     

     

    Jarvis didn’t address this, but there is the problem with the concept of the midtarsal joint having a fixed oblique and longitudinal axes.   If the midtarsal joint doesn’t move about those axes, then you can’t be maximally pronated about those axes.   More recent  examination of midtarsal joint motion has shown that in walking the midtarsal joint doesn’t move about those axes.   So, we could have discarded the Root postulate before the Jarvis paper.   On the other hand, the orthotics that Mert Root made did work.   So we do need to explain why they did work.   Perhaps there is some other explanation than they work because the foot was cast with the midtarsal joint pronated.

     

    Daryl wrote.

    First let us look at the selection of the individuals for the Jarvis study to find out if there is a bias.  …….. should quickly identify that this study cannot really predict who will develop symptoms and who will not develop symptoms in a general population.

     

    Yes, but the study can  look at the validity of the Root measurements for the  population that was in the study.  The study can conclude that  the measurements were not predictive for the population studied.   So, we have some evidence that the measurements were not predictive for this population.   We have no evidence that the Root measurements  are predictive for the whole population.   And we have some evidence that they don’t work in a limited population.    Why weren’t the measurements not predictive in this population.  Perhaps they are not predictive for the  whole population.   Can you come up with a theory on why this populations the measurements were not  predictive and they would be predictive for the whole population?

     

    Daryl wrote: 

    The next thing to note is that the authors made the study into a straw man argument by identifying only 5 independent variables.  Neutral calcaneal stance position, resting calcaneal stance position, passive ankle joint dorsiflexion, first MTPJ joint range of motion and frontal plane forefoot to rearfoot position.  This certainly in no way represents the full scope of a Root-anthropometric examination.  Anyone who ever read or listened to Root, knows that he stated that if a person had more than 3° of forefoot varus, they would fully pronate their subtalar joint in static stance.  What Root never said was that if a person had less than 3° of forefoot varus they wouldn’t pronate.   I have seen many people with forefoot valgus and abnormally pronated feet.  Root identified many causes of pronation other than forefoot and rearfoot abnormalities.  For example he claimed that people with internal tibial torsion would pronate their subtalar joint abnormally, whether they had normal or abnormal rearfoot or forefoot abnormalities.  Did the study also eliminate all the other abnormalities that Root talked about?

     

    So, how do functional foot orthoses address these other causes of pronation.  Now we are back to the problem  of what exactly is Root theory.     When  early astronomers were  having difficulty explaining the motions of the planets and the stars when they thought the Earth was the center of the solar system they had to keep adding special  exceptions (epicycles) for when the planets did not move as expected.    Are the other causes of pronation  just Root’s attempt to add epicycles to the explanation of what causes pronation.  Is there  any evidence that internal  tibial torsion causes pronation?  Neutral position is not the center of foot universe.  Believing that it is is getting in the way of the ability to do science on the foot.

     

     

  • Excellent contributions from Dr. Phillips and Dr. Richie.

    Those with the least experience of the process of traditional assessment and treatment seem keen to call a 'foul' on the Root postulate with a tenacity bordering on obsession. How many own a copy, and have read, the work of Root, Orien & Weed. I believe to this day this work remains a good foundational base upon which to build and incorporate understanding and knowledge.

    A wise teacher told me, many years ago, that a good paper does not only challenge conventional understanding and wisdom but offers a better and more robust alternative. If the author cannot do so, what is the purpose of the publication.

    It will serve the professions and our patients much better to focus the research effort on new discoveries and enhancements.  

  • Defending a Prejudiced Assault on the Root Theory
    By:  Douglas Richie Jr.  DPM

    When Root, Weed and Orien published their seminal text “Normal and Abnormal Function of the Foot” in 1977, I was a second year student at the California College of Podiatric Medicine. (1)  For the students at CCPM, this textbook was a pivotal part of our education as it provided a comprehensive description of all that we were being taught in our biomechanics courses.  It was a welcome and useable resource since all we had prior to this book were our lecture notes and handouts from a sum total of five courses in biomechanics.

    The “Root Theory”is based on much more than this single publication.  Prior to the 1977 publication, Root, Orien and Weed had already published their examination techniques and their “criteria for normalcy” of the human foot. (2) It was this publication which proposed a nomenclature which all professions could recognize as well as a starting point reference of alignment known as the neutral position of the subtalar joint (2)  Even before that, Root had been teaching his techniques for neutral suspension casting and fabrication of “functional foot orthoses” which were being implemented around  the country with widespread acceptance by the time of the 1977 publication. Root shared his insights and techniques with all competing foot orthotic labs in the United States without claiming any proprietary interest. (3)

    Therefore, the book Normal and Abnormal Function of the Foot” expanded on previous work, but also provided a comprehensive view of lower extremity function which reflected the body of scientific knowledge at that time.  The most valuable and enduring parts of this book are the sections on gait, muscle function and pathomechanics of common foot disorders.  Interestingly, few of these specific sections of the book have been challenged to any significant degree since the date of publication.  Instead, researchers and clinicians have continued to question the Root et al definition of “normalcy”, the relevance of subtalar neutral position, and whether “abnormal” foot function can be predicted by static measurements.

    The fact that 40 years later, the observations and theories of Root et al are still being debated and challenged validates the monumental impact that these three teachers have had on our profession and on many  practitioners around the world. No collection of published work from our profession has had such a profound effect over such a long period of time.

    When Merton Root was first challenged on some of his observations and conclusions about normal and abnormal foot function, he speculated that much of the content of his teachings and writings would be tested and then either validated or disproven. He encouraged that process.  Indeed it was not long after 1977 that modern gait laboratories using breakthrough technologies and measurement techniques began examining and testing various parts of the “Root Theory” to determine if the conclusions were accurate.

    Many students of Root et al also began questioning the importance of measuring forefoot to rearfoot relationships.  In the clinic, we would see a patient with high degree of forefoot valgus who walked with severe pronation: the opposite of what we would expect.   John Weed and other attendings would address this dilemma by asking us to examine other parameters such as femoral position and we would quickly appreciate that rearfoot alignment could be easily influenced by factors more proximal up the kinetic chain.  

    We also struggled with our own accuracy and reproducibility of measurements as taught by the faculty at CCPM who were all trained by Root et al.   We would all measure the same patient in the clinic and come up with different measurements.  However, when we watched the patient walk we would usually agree with what we saw.  Root, Orien and Weed always put the greatest emphasis on gait analysis in detecting pathology and measuring success of foot orthotic therapy.

    The authors of a recently published paper, Jarvis et al do an excellent job of summarizing all of the key research articles published over the past 30 years which cast doubt or actually refute several key components of the “Root Theory.” (2)  In fact, each and every static measurement advocated by Root which determined “normalcy” of the human foot and which were tested by Jarvis et al had already been refuted by several quality published studies in the past.   The key finding of the Jarvis study was summarized by their statement, “It is important to understand why static measures are so poorly related to dynamic foot kinematics, which is an outcome of this, but also other literature”.  They cite four previous studies which had drawn this same conclusion, all published between 1999 and 2015. (3-6).  This poses the question:  “Is there anything new here which should change the way we treat our patients?”
    Critics of the “Root Theory” have been recently embracing the so-called “Tissue Stress Theory” of orthotic therapy.   This theory was originally described by McPoil and Hunt who advocated a new strategy for foot orthotic intervention based solely upon anecdotal evidence. (7)  Others have used this notion to validate their own orthotic outcomes, but none have actually conducted clinical trials to test the efficacy of this type of orthotic strategy intervention. (8) This notion of  “Tissue Stress Intervention” was again propagated  by Javis et al who state “It follows that orthotic prescriptions might target changing stresses in specific (painful or at risk) structures rather than achievement of seemingly erroneous skeletal alignments. “  However, Jarvis et al do not cite any credible references which validate this approach to foot orthotic therapy.  That is because there are no such studies.

    It is ironic that many of the terms used by tissue stress advocates and the evaluation and interventions to relieve tissue stress in the lower extremity actually began with Root’s work.   Tissue stress relieving orthotic therapy has not been tested in any randomized controlled trials.  Suggestions about using certain orthotic designs to relieve stress on a specific anatomic structure are predicated upon pure speculation.   I would challenge any proponent of tissue stress orthotic therapy to explain what forces cause plantar fasciopathy and what specific orthotic design reliably mitigates those stresses or forces.  That question alone has been explored in many high quality laboratory studies and the answer today still remains elusive.

    So while the Jarvis et al study only validated previous works refuting the Root notion of static measurements to predict dynamic foot function, the disturbing message in this paper was the almost spiteful conclusion stated by the authors: “We recommend that clinicians stop using the Root et al. biomechanical examination protocol.”  They further state:  “Based on the results here and the related literature over the last twenty years, we believe that the assessment protocol advocated by Root et al.  is no longer a suitable basis for professional practice.” Pray tell, if we are to stop evaluating patients with techniques which have worked for us over the past 40 years, what evaluation method should we now embrace?  What method does Jarvis et al find “suitable” in their own clinical practices? Tissue stress?

    With all due respect to Jarvis et al, many of the teachings of Root et al have been accepted in various forms and have become essential components of treatment of lower extremity pathologies by a wide range of specialties around the world.   The assessment of the human foot, the terminology to describe the relationships of the component parts of the lower extremity and the perception of what types of stresses that deforming forces will impose on the structures of the lower extremity as originally taught by Root et al permeates all the major textbooks and teaching manuals in the fields of orthopedics, podiatry, pedorthics, and rehabilitative medicine.

    Consider McGlamry’s Comprehensive Text Book of Foot and Ankle Surgery, 4th edition which was published in 2013 as well as Coughlin and Mann’s 9th Edition Surgery of the Foot and Ankle.   Throughout both of these gold standard surgical textbooks, written from the orthopedic and podiatric professions, the terms forefoot varus, forefoot valgus, rearfoot varus, plantarflexed first ray and neutral rearfoot position are found.  Furthermore, surgical procedures are described and advocated to correct these deformities.   It is universally accepted in these textbooks that a forefoot deformity such as an acquired supinatus or forefoot varus, as seen in adult acquired flatfoot, will cause pronation compensation in the rearfoot.  It is also advocated that a plantarflexed first ray, as seen in cavus deformity will cause rearfoot supination compensation.   Cavus foot surgery approaches the forefoot primarily to correct rearfoot alignment.   

    Surgical procedures to correct foot deformities such as the adult acquired flatfoot follow the Root principle of aligning the rearfoot  perpendicular to the ground and reducing any acquired forefoot varus.   The deforming force of the gastroc-soleus on flatfoot deformity is universally accepted and procedures such as the gastrocnemius recession are the mainstay in flatfoot surgery.

    Thus the influence of forefoot to rearfoot deformities in the development of pathologies in the lower extremity has been well accepted in the surgical community. The notion of restoring the alignment of the foot to an optimal position with surgical procedures follows the Root theory in almost every regard.   Furthermore, the pre-surgical assessment of our patients still requires some type of static examination, including static radiographic measurements.  On the operating table, we measure range of motion of the 1st MTP, the degree of stiffness or “hypermobility” of the first ray, the alignment of the calcaneus after an osteotomy and the range of ankle joint dorsiflexion after a gastroc recession.   Are we to immediately “stop using” these measurements and assessments in clinical practice just because a group of researchers tell us so?  Are we to switch to some other type of theory or measurement technique which has yet to be validated in clinical trials?

    In spite of a relatively small group of critics, the mainstream of lower extremity clinicians embody and implement many parts of the “Root Theory” in everyday practice.  They do so because their treatment protocols seem to work.  Whether using foot orthotic therapy or surgical procedures, we do not keep implementing treatments which do not work. We implement procedures and treatments which reliably work for us and for our patients.  The fact that the foot orthotic industry has grown exponentially since Root first taught his principles 40 years ago must validate that something was right about his proposed treatments.

    Keep in mind that the study published by Jarvis et al did not measure efficacy of foot orthotic therapy as taught by Root.  It only tested static measures of the foot and ankle and the value of these measures to predict alignment of the foot during gait. Although Jarvis et al took the liberty to challenge how we decide which patients should be given foot orthotic therapy, their study did not directly measure or test this intervention.

     As far as measuring outcomes with “Root Functional Orthoses” there are many published studies showing favorable outcomes.  There is nothing in the Jarvis et al study to substantiate any assertion that we should abandon the casting technique, fabrication technique and prescription criteria for foot orthotic therapy as taught by Root et al. Foot orthotic therapy has been and will continue to be the mainstay of non-operative interventions in podiatric practice for years to come.

    This leads to the most troubling pronouncement made by Jarvis et al in their discussion of their findings.  They make the unfounded assertion that the so- called “deformities” described by Root et al have “no clinical relevance.”  Tell this to a patient with Charcot Marie Tooth Disease with 20 degrees of forefoot valgus and who is forced to walk on the side of their foot.  Tell this to a patient with 20 degrees of acquired forefoot supinatus and a Stage 3 Adult Acquired Flatfoot Deformity who walks with severe sinus tarsi pain.  Yes, Jarvis et al only measured kinematic variables related to foot deformities and ignored the far more significant kinetic forces which arise from these mal-alignments.

    Furthermore, Jarvis et al suggest that since the “deformities” defined by  Root  do not cause symptoms, then they should not be treated. They state:  “if the deformities described by Root et al are the basis for prescribing some foot orthoses, then evidence that the so called deformities have no functional relevance, is perhaps evidence that foot orthoses should not be used in the absence of symptoms and simply to “correct” deformities.”  Any student of Root or his colleagues could verify that they were never taught to intervene with foot orthotic therapy to simply  “correct deformities.”  To attribute such an irresponsible abuse of orthotic treatment to Root et al demonstrates a total lack of respect for the integrity of these pioneers of podiatric biomechanics.   Anyone who studied under Root and his colleagues would know that such a flagrant misuse of foot orthotic therapy would have been condemned by these stellar professionals.  To suggest that such an abuse of a valid therapy was ever advocated by Root et al casts a cloud of uncertainty regarding the motives of Jarvis et al in the conduction of their study and the formulation of their conclusions.

    Yes, in this study of self-reported healthy individuals age 18 -45, no correlation with static measurements and predicted gait patterns as originally advocated by Root et al could be measured. All of the static measurements of the subjects were performed by one single assessor with presumably no bias against Root et al.   Yet the sweeping condemnation of Root et al by the authors in areas far beyond the findings of this study leaves the reader with many questions about the true motivation of the study.

     his study by Jarvis et al by no means invalidates the entirety of what Root contributed to our knowledge and clinical practice today.  For that, we should all be grateful and respectful as we provide commentary and suggestions for improvement in all aspects of podiatric care.

    REFERENCES


    1.     Root M, Weed J, Orien W. Normal and abnormal function of the foot. 1 edn. Los Angeles: Clinical Biomechanics Corporation; 1977. 

    2.     Root ML, Weed JH, Orien WP. Neutral Position Casting Techniques. Clinical Biomechanics Corp., Los Angeles, 1971.
    3.     Root ML, Orien WP, Weed JH, Hughes RJ. Biomechanical Examination of the Foot, Volume 1. Clinical Biomechanics Corporation, Los Angeles, 1971.
    4.     Root ML. How was the Root functional orthotic developed? Podiatry Arts Lab Newsletter, Pekin, Illinois, Fall 1981.
    5.    Jarvis H, Nester C, et al. Challenging the foundations of the clinical model of foot function: further evidence the root model assessments fail to appropriately classify foot function. Journal of Foot and Ankle Research, 2017; 10(7).
    6.    Buldt AK, Murley GS, Levinger P, Menz HB, Nester CJ, Landorf KB. Are clinical measures of foot posture and mobility associated with foot kinematics when walking? J Foot Ankle Res. 2015;8:63.
    7.    Buldt AK, Murley GS, Butterworth P, Levinger P, Menz HB, Landorf KB. The relationship between foot posture and lower limb kinematics during walking: a systematic review. Gait Posture. 2013;38:363–72.
    8.    McPoil T, Cornwall MW. Relationship between neutral subtalar joint position and pattern of rearfoot motion during walking. Foot Ankle Int. 1994;15:141–5.
    9.    Cornwall MW, McPoil TG. Effect of ankle dorsiflexion range of motion on rearfoot motion during walking. J Am Podiatr Med Assoc. 1999;89:272–7.
    10.    McPoil TG, Hunt GC.  Evaluation and management of foot and ankle disorders: present problems and future directions.  J Orthop Sports Phys Ther. 1995 Jun;21(6):381-8.
    11.    Harradine, P; Bevan, L. A review of the theoretical unified approach to podiatric biomechanics in relation to foot orthoses therapy.   J Am Podiatr Med Assoc. 2009; 99: 317-325

  • This is a refreshing topic as I find most younger podiatrists have little concern or maybe input to custom orthotics because they appear not to understand/taught biomechanics from someone rooted in Dr Root.

    Dr Phillips does a great job in breaking down these newer articles. 

    In my practice I find Roots theories outside of surgery apply well to my fabrication of orthotics.  Recently however, I have changed from the traditional non-weight bearing neutral suspension casting to the Sole Support method ( semi weight-bearing).  I notice an improved control and results via this technique in that it captures the entire foot arch and does not allow for give ( the old way we added addition plaster to the longitudinal medial arch in response to this sagital plane motion).   My question now is, as Dr Phillips points out, that Root's casting method is to capture the MTJ fully pronated, the semi-weight bearing casting technique via the Sole-Support method does not fully lock the MTJ.....or does it?

    If Sole-Support technique does not fully lock the MTJ , then what is it that is making this custom orthotic more functional then the traditional Root casting?  Or, if it does fully lock the MTJ, how is this done? I do the technique well enough but I don't understand how it can fully lock the MTJ.

     

    thank you

  • I would like to thank Dr. Shapiro for his looking at some of the new literature in regards to biomechanical research and questioning some of the beliefs in traditional ideas and methodologies.  Every one of us should be doing that every day in every aspect of the way we think and practice, for in doing so, breakthroughs are made.   However I believe that Dr. Shapiro has also fallen into some common literature traps.  One of these traps is what is often called “the straw man” in that the position is not accurately portrayed and then we knock down that position.  Another is the belief that the newest literature is the best literature, that there are no flaws in the methodology.  So I would like to address a few of the points that Dr. Shapiro brings up.

    First we have to ask ourselves, “What is Root theory?”  Dr. Root put forward a whole concept of what made for the optimal foot function in all of the joints of the foot and also for trying to classify feet as to etiologies of abnormal function, and also for a change in the way that orthotics are molded and modified to try to promote a foot function that is closer to the ideal. So when one questions Root theory one really should say what exact Root principle they are talking about.

    As I have analyzed the pre-Root literature, I find that most of the Root concepts were already in the literature.  There is only one concept that I can’t find pre-dated Root and that is what I have come to call “The Root Postulate.”  This is the concept that the midtarsal joint is in its optimal position when it is fully pronated around all its axes.  As a result, Root modified the casting of feet from a semiweightbearing state to a nonweightbearing state so that the shape of the plantar foot could be captured with the midtarsal joint in its maximally pronated state.  As I have read the literature, I find that Steindler (1929) proposed that a flat foot be corrected with a varus wedge under the heel of the shoe and a valgus wedge under the forefoot.  In other words, Root’s concept captured the Steindler idea, putting it inside the shoe instead of outside the shoe.  Of course there are many orthotics made from semiweightbearing casts that very adequately alleviate the symptoms of the patient, and there is much research yet to be done in how the shape on the differences in the shape of orthotics made from nonweightbearing and semiweightbearing casts.  So has Jarvis, et al. disproved The Root Postulate?  I find nothing in the paper to question that postulate.  Before one puts Root in the trash bin, we need to first disprove this - what I consider the most important of all the Root concepts.

    When examining any study, the methodology is so important to evaluate.  First let us look at the selection of the individuals for the Jarvis study to find out if there is a bias.  The study specifically advertised for healthy individuals.  That means that people who already felt they didn’t qualify would not apply.  This means, then, that this sample is not a cross sectional study of the population in this age group, only a cross sectional study of those who had already met their own inclusion/exclusion criteria.  Then after this self-identification, another 28.5% of these individuals who identified themselves as healthy, who were less than middle age, have symptoms were still excluded from the study?  We are given a list of exclusion criteria, including hallux valgus presence, but we have no information about the breakout of all of the various exclusion criteria in these healthy people.  One should quickly identify that this study cannot really predict who will develop symptoms and who will not develop symptoms in a general population.

                    The second issue is that the Root definition of a normal foot was one that could function a lifetime without physical deformity or pain.  When looking at the population studied, the average age of the participants was approximately 32 years old, which is less than half of their life expectancy.  This is a common fallacy of many researchers, they don’t sample the middle age and geriatric population to find out what the end result is, they assume that if a person reaches age 32 without symptoms that no symptoms will result and no prophylactic therapy is needed.  It should also be noted that the participants in the study were at an age when they had maximum biomechanical integrity of their muscles and skin and soft tissues.  What we really want to know is what happens over the next 32 years, as the soft tissues start to develop advanced glysylation endproducts and peripheral vascular disease as well as muscle weaknesses.  The fact that young soft tissues can withstand a lot of pounding without developing symptoms does not mean that this will continue ad infinatum.  If the researchers want to really study who can be determined to have a normal foot, they will choose a true cross section of the population who have reached aged 75, and compare those without hallux valgus and those with hallux valgus, or any other single variable.  Because of the bias in the study population, we can automatically reject conclusion #5, that foot orthoses should not be used in the absence of symptoms.  Yes, we will find those septuagenarians who have abnormally functioning feet who will not develop symptoms, but likewise we will find septuagenarians who smoke who have no respiratory problems.  The idea that prophylactic therapy is never needed in the foot function arena is counterproductive to the future health of the public.

    The next thing to note is that the authors made the study into a straw man argument by identifying only 5 independent variables.  Neutral calcaneal stance position, resting calcaneal stance position, passive ankle joint dorsiflexion, first MTPJ joint range of motion and frontal plane forefoot to rearfoot position.  This certainly in no way represents the full scope of a Root-anthropometric examination.  Anyone who ever read or listened to Root, knows that he stated that if a person had more than 3° of forefoot varus, they would fully pronate their subtalar joint in static stance.  What Root never said was that if a person had less than 3° of forefoot varus they wouldn’t pronate.   I have seen many people with forefoot valgus and abnormally pronated feet.  Root identified many causes of pronation other than forefoot and rearfoot abnormalities.  For example he claimed that people with internal tibial torsion would pronate their subtalar joint abnormally, whether they had normal or abnormal rearfoot or forefoot abnormalities.  Did the study also eliminate all the other abnormalities that Root talked about?

    It should be pointed out that in 1994, at the first John H. Weed Memorial Seminar, held in Lake Tahoe, Merton Root pointed out that he was surprised that his 1977 work had lasted as long as it had, that he had expected the text to be totally outdated within 5 years of its publication.  He never intended for his ideas not to be superseded by better and more sophisticated ideas.  He was always looking for better concepts.  Dr. John Weed was a great supporter of Dr. Kevin Kirby in his young days as he looked for more information about the subtalar joint axis.  Dr. Root helped Dr. Richard Blake in his development of the inverted orthotics.  He was very excited with my first publication about how the forefoot to rearfoot relationship changes in relationship to the subtalar joint position.  He never rejected new technologies.  I always found Dr. Root to be a very open minded person, but to be a very critical thinker.  Dr. Shapiro talks about the scientific method being brutal in its unflinchingly turning away from previously held truths.  In being brutal, we have to be brutal in our examining the methodologies to find out which scientific methodologies truly eliminate bias and which ones do not.  I find in Jarvis’ work some very good information, yet after reading his data, I do not come up with the same conclusions that he does.  Newer definitions and additional technologies do not mean that we totally eliminate the concepts of the past to get us to the desired goal.  We certainly did not need the Hubble telescope to get us to the moon, we did it just fine with old-fashioned Newtonian mechanics.  That doesn’t mean that the Hubble can’t give us better understanding of the universe nor that Newton is useless.  As I noted above, we talk about Root biomechanics as if it is a single entity.  Biomechanics is a subject, Root was one person who added to our understanding of biomechanics.  He was not the beginning and he is not the end.  His classification system is helpful in identifying some patients with potential problems as well as in treating many individuals successfully.  Those who teach Root as the only thing we need to know about biomechanics of the foot do not carry forth the Root philosophy nor his vision.  Those who want to totally trash Root likewise turn a blind eye to their own inconsistencies and failures to understand who Root was and what he was trying to do.  It’s time to look at individual statements about Root’s theories and truly trying to test each one.  As an example, having done some serious research work on ankle joint dorsiflexion, I will state that the concept ankle equinus is one that needs to be greatly expanded as to what we are really measuring and what all the compensations and consequences are.  Do I believe that Root was overly simplistic in his examination and explanations, and I have to say “yes.”  Was he totally wrong and I have to say, “no.”  Just as Euler added to the Pythagorean mathematics, so we need to consider the full scope and breadth of all the mechanical theory and studies.  It is important to remember that studies only reinforce our faith in theories, they never prove or disprove them.  I find that Jarvis’ work only adds to my total knowledge base, but does not eliminate most of the Root concepts that I find still useful.