What is the "normal foot"?

Hi All,

I don't think anyone could dispute that foot problems are multifactoral, nor that one of the factors is that we live longer (I'll be pedantic for a sec and add that living longer without being particularly acitive would probably be more likely to cause problems elsewhere!).

The point here is that we have based a whole science around what was written in the 60's (some of it in 1941 or thereabouts - that experiment was duplicated by Root et al in 1966, however nothing wrong with that.

IMO we as a profession (and I'm pretty sure about this here in the UK) seem to be clinging to the Root paradigm, even in the face of evidence which strongly suggests that normal feet are not heel and forefoot in the same plane when the STJ is placed in neutral etc etc.

Our feet were designed for a multitude of different types of supporting surface.s
Put them on one surface for a length of time (say 90% of 60 years as a guesstimate), and throw in some variables like age, activity level, systemic disease, bodyweight) and you will eventually have symptomology.
Thats how simple it is.
Thats why, even without changing the variables, we can often make a huge difference to the symptoms simply by changing the foot mechanics.

Dr LCT2.
You wrote
"Which forums have you presented your ideas at? Audiences of mine haven't been all that receptive to the idea. I think it's so simple that it flys in the face of intellectualization which is a pretty good pastime for some;"

That sums it up pretty much for me too!

Regards,
davidh

 

>Did Mert Root apply his criteria for mechanical normalcy to the present day surface of hard, flat terrain.

The authors do make quite a point regarding normalcy and the temporal circumstances, which determine that definition. Analysis was done on flat surfaces but there are many more variables involved.

The challenge with Root and Inman's works on flat surface analysis was the interface i.e. barefoot to flat surface. This would not be the same as the foot shoe and ground. Fine for the time when analysing the spatial temporal behaviour of the weightbearing joints but much less accurate in the below ankle complexes. At best this has remained a guesstimate. Technologies, which purport to now measure shear and better interfacing with the foot and shoe, are more likely to advance gait analysis than has been the case in the last thirty years. So what is coming is more likely to be revealing than what has come to pass. As more data is collected then more interesting observations appear, such as commonality prefers a varus foot. We seem to be moving from the simplistic medical model of normality (hypothetical ideal) to a more pluralist phenomenon, consistent with a range of physical features.


Furthermore, we can alter the forces that the ground applies to the foot, rather than alter the ground.

How would you achieve that ?

I always thought the Romans laid flat ( sorry Cameron, slightly convex) roads to aid vehicles with wheels and less so for ambulating soldiers.

Romans laid roads certainly but flat is not an adjective I would use to describe them. More compact than loose earth and likely therefore to withstand the impacts of marching soldiers but cobbled in nature and definitely a challenge to walk upon. We need to wait for the invention of Tarmacadam (20th century) before we begin to see flat style pathways which were still very irregular. There is a good history site "From dirt to concrete" at <http://www.ugcs.caltech.edu/~jlin/lincoln/history/part3.html>

So really the kind of flat walking surfaces caught in vitro on walkways in the 20th century has never existed for perambulation other than in dwellings where people go barefoot. Despite all else we still do not quite understand the role of the shoe but can only assume it (and inclusion) is the ultimate foot orthosis.

Chers
Cameron

 

To all who have contributed to this thread,

I have thoroughly enjoyed the excellent discourse which has so characterised this thread. I don't really have much to add to what has already been stated, but would like to respond to Peter who asked: "Did Mert Root apply his criteria for mechanical normalcy to the present day surface of hard, flat terrain?" My answer to this is yes. In 'Biomechanics of the Foot: Volume I' (Root, Orien, Weed and Hughes - 1971), a definition was framed as to what constitutes a normal foot and it largely reflected the foot-oriented lineaments of the biophysical criteria for normalcy. The definition ran as follows:

"The term normal represents a set of circumstances whereby the foot will function in a manner which will not create adverse physical or emotional response in the individual. This definition applies when the lower extremity is used in an average manner and in an average environment, as dictated by the needs of society at the moment."

The 'set of circumstances' as mentioned in the definition was meant to represent the a priori derived biophysical criteria of normalcy, and the phrase "used in an average manner and in an average environment" could be construed as meaning functioning on an industrialised walking surface and encased in a shoe. However, as we all know, there are shoes and there are shoes!

I wholeheartedly agree with Kevin that over-emphasising hard flat surfaces as a cause of pedal pathology does not paint an adequate picture of its multifactorial causation, but I would also venture a rider by saying that it certainly may be part of the equation in some pathologies. Cultural evolution is a much more accelerated phenomenon than biological evolution and our feet (which have biologically evolved to function on a 'natural' varied terrain) must have had quite a 'culture shock' when there were 'suddenly' presented with an artificially flat walking environment. Indeed, in connection with this, the American podiatrist Charles Turchin has been attributed as stating: "Man has an evolutionary foot in a revolutionary society".

Regarding 'Podopaediatrics' by Herman Tax, an edition was published back in 1947, but it was privately published, and Tax had been writing on the child's foot as early as the early 1940s in the Journal of the National Association of Chiropodists (now J.A.P.M.A.).

Finally, just a thought about the employment of the term 'paradigm' when describing Root's clinical system of approach (or indeed, any of the other clinical systems of approach). Root's system of approach is a 'model', not a 'paradigm'. According to Thomas Kuhn (who popularised the term but by no means coined it), the term 'paradigm' designated a group of ideas, theories and concepts which were 'universally' assented to by a community of researchers (or in the case of podiatry, academicians and clinicians). No 'universal consensus' has ever been displayed by the world-wide podiatric community in the context of the Root model. It has had very wide consensus, but in no way has it ever been universal. Therefore, it could be more appositely described as a 'dominant model' within the podiatric community. However, other clinical/theoretical models are also circulating about the clinical arena which also command a wide consensus such as the work of Kevin Kirby, Eric Fuller and Howard Dananberg. These, likewise, are 'models' and not 'paradigms'. Perhaps therefore we should stop using the term 'paradigm' as a label for these models. Am I being overly pedantic in suggesting this?

Finally, in a paper published in 2001, I discussed at length the concept of normality and the many definitions which had been formulated in the past to 'paint a picture' of the normal foot. The reference is as follows:

Lee, W. E. (2001) Podiatric Biomechanics: An historical appraisal and discussion of the Root model as a clinical system of approach in the present context of theoretical uncertainty. Clinics in Podiatric Medicine and Surgery. 18(4): 555-684.

Respectfully,

Eric Lee.

 

Charlesworth??? Where did that one come from, Eric?

Always good to get Eric Lee's opinions on these matters since I alway enjoy reading his postings.

Like Eric stated, the ideas of Root et al and others are really best described as models and not paradigms. However, in my Encarta dictionary, it lists the fourth definition of paradigm as follows:

"relationship of ideas to one another: in the philosophy of science, a generally accepted model of how ideas relate to one another, forming a conceptual framework within which scientific research is carried out."

Therefore, one could then make an argument that any model that is generally accepted at any instant in time by a scientific community could be considered a paradigm. The question then becomes: Were the teachings of Root et al ever "generally accepted"?

In California, between 1970-1985, then I would have to say yes. However, I believe that the Root et al model has become less "generally accepted" within the podiatric profession in the past 20 years. Eric Fuller and I also mention the concepts of Kuhn regarding the dynamics of paradigms within the scientific community in our chapter in Stephen Albert's book (of which Eric Lee was luckily also a contributor).

By the way, I do like the "dominant model" label, Eric. I think one could certainly make an argument for Root et al's theories being a paradigm at one time. I suppose it all depends on how one chooses to define paradigm. Until this is settled, it is probably safer to talk about the cumulative theories of Root et al as being the dominant model of podiatric biomechanics of the 1970's and early 1980's.

 

Kevin

> Charlesworth??? Where did that one come from, Eric?

Franklin Charlesworth, the Godfather of UK foot orthotics. He was seminal in the US too, and predates Root et al by a couple of decades.

>Always good to get Eric Lee's opinions on these matters since I alway enjoy reading his postings.

Me too.

>in my Encarta dictionary, it lists the fourth definition of paradigm as follows:

"relationship of ideas to one another: in the philosophy of science, a generally accepted model of how ideas relate to one another, forming a conceptual framework within which scientific research is carried out."

Not sure Root's model could be classed as pure science, but certainly has a hypothetical component to it with is consistent with first principles.

>Therefore, one could then make an argument that any model that is generally accepted at any instant in time by a scientific community could be considered a paradigm.

Again I think podatry described as a scientific community would stretch the point, even today. Accepted conventional wisdom within a professional group would be a better description to meet the criteria for paradigm.

The question then becomes: Were the teachings of Root et al ever "generally accepted"?

>In California, between 1970-1985, then I would have to say yes. However, I believe that the Root et al model has become less "generally accepted" within the podiatric profession in the past 20 years.

From my reading of Volume II, this was the intention of the original authors. Never was the text supposed to be definitive and expectation of a Volume III was anticipated. So it is fitting this development should come from California.


> Eric Fuller and I also mention the concepts of Kuhn regarding the dynamics of paradigms within the scientific community in our chapter in Stephen Albert's book (of which Eric Lee was luckily also a contributor).

Craig Pain too has written extensively on this topic for many years.

>By the way, I do like the "dominant model" label, Eric. I think one could certainly make an argument for Root et al's theories being a paradigm at one time. I suppose it all depends on how one chooses to define paradigm. Until this is settled, it is probably safer to talk about the cumulative theories of Root et al as being the dominant model of podiatric biomechanics of the 1970's and early 1980's.

I would agree. The paradigm shift represented by the Root model was a quantum leap however from that which existed before. Hence has become a milestone in conceptional thinking. As stated previously I believe the next leap has yet to come and will be achieved through new technologies. The sterling works of yourself and others has shown the dominant model is imperfect but applicable. Craig Payne's Sagittal model is however a credible alternative.


Cheers
Cameron

 

Kevin.
you wrote (in response to Charlesworth)
"Until this is settled, it is probably safer to talk about the cumulative theories of Root et al as being the dominant model of podiatric biomechanics of the 1970's and early 1980's."

Now I thought Rootian biomech was still being taught, and not as historical interest but as a (or the) paradigm for practical biomech.

Of course in the UK in 2005 it still is by all the companies (excluding mine) who run short 2 or 3 day courses.

Any comments from you educators out there?

Regards,
davidh

 

Hi Dave

>Now I thought Rootian biomech was still being taught, and not as historical interest but as a (or the) paradigm for practical biomech.

Speaking for the centres of education I have been involved with thr answer would be yes.

My own biomechanical lectures follow Whittle's text on Gait Analysis with podiatric biomechanic interjections (mostly form Mauchard and Payne) . In the labs the students were encourgaed to conduct scientific experiments on accuracy, validity and reliability and as an academic exercise to report reflectively upon the gait and foot analysis using constructive informed opinion.


> Of course in the UK in 2005 it still is by all the companies (excluding mine) who run short 2 or 3 day courses.

In Australasia there is heavy dependence on prescription services by practitioners and undergraduates would use these services to supply clients in supervised clinics.

Many of the independent foot orthotic services differ in their prescription writing and casting techniques, senior students would have access to in service training which would include standard foot casting. Foot orthotic companies tendered for service and some requested as part of their contract that no other casting technique was used (other than their own) In any event students had previous undertaken scientific experiments to rate supine/prone and semi weightbearing techniques and would employ the requested approach from an informed backgound.

Students were also introduced to the conventions of popular podiatric examination, diagnoses and orthotic prescrition and were required to provide a portfolio of work, involving actual documented patient care.

So in summary the biomechnaical curriculum engulfed much wider aspects of three dimensional motion than the sub talar neutral model but when necessary (as in biomechanical numenclature and foot orthotic prescription) did incorporate the convention.


I assume this is common to most centres of podiatry education.

Cameron

 

Ian:

The views you give above have been commonplace here in the States for some time now. Having lectured in many national and international venues over the past 20 years, I have noted regional distribution of "pockets" of practitioners who are very keen on the ideas of Root et al, and others who are against his ideas. I first published my series on "innaccuracies in podiatric biomechanics dogma"(i.e. Root et al theories) in 1990 and have been lecturing on them, here in the States, since 1985 (Kirby KA: "Inaccuracies in Podiatric Biomechanics Dogma - Volumes I, II and III" in: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997, pp. 7-12).

Therefore, maybe in your geographical area, podiatrists are less aware of the alternative models of foot function that have been advanced, than they are here in California and the US.

However, in regards to biomechanical measurements, I still do these on a daily basis on my patients receiving orthoses and find them quite helpful in classifying foot types, ranges of motion of joints, and structural deformities of the foot and lower extremity. The measurements don't take me more than 5 minutes to perform on most patients. I still teach these measurement techniques to the third year podiatric surgical residents that I train every week in biomechanics and sports medicine since I consider them a valuable addition to their clinical skills.

Without these skills, these highly trained podiatric surgeons would be less able to classify foot and lower extremity structure and function for themselves and when communicating to other podiatrists and foot orthosis laboratories regarding their patients. I don't consider these measurements "innaccurate or unnecessary" in my hands. However, I do consider the measurements innaccurate when the residents make their first few sets of measurements. Their measurements always become much more accurate and reproducible after four months of training in my office.

It is just like surgery...the more you do it and the more you pay close attention to detail, the better you become at the skill.

 

Hi Kevin

Thank you for your reply. One question that arises for me is what time of day do you take the measurement or do you take them a couple of times in a day.

The reason behind the question is related to the issue of diurnal variation which can mean an increase or decrease in the available rom of a joint over a 12 or 24 hour period. So the rom at 7 in the morning could be different from say 5 in the evening.

I can agree that experience enables you to measure more efficiently but that is different to a suggestion that the measurment is more accurate. Like yourself I am very comfortable with drawing lines etc however:

We are essentially measuring soft tissue
drawing a straight line along a limb that bows
Usually with instruments whose calibrations can be woefully inaccurate
Plus other reasons.

To feel the rom and visually observe it and note it is understandable and correct. Indeed it would be poor clinical practice if we didn't. However I cannot agree that accurate values can arise from it.

For these reasons I feel actual measurements appear a pointless exercise.

Regards and enjoying the thread
Ian

 

Craig Payne's Contributions to Podiatry

Cameron:

I always enjoy your postings also, Cameron. Good to see you are still very alive and active in your educational pursuits. Maybe we can hook up in Melbourne while I'm lecturing there in October?

I wanted to publicly state that I totally agree with your analysis of Craig Payne's contributions to podiatry and biomechanics. There is probably no other podiatrist in the world in the past decade that has done more to advance knowledge in podiatric biomechanics than has Craig Payne. I have learned very much from his intellectual discussions and research and think he is one of the great minds and personalities within the international podiatric biomechancs community. Craig has certainly been at the forefront of the many positive changes we have seen in the teaching of podiatric biomechanics throughout the international podiatric medical community and I am looking forward to his continuing contributions toward developing a better understanding of foot and lower extremity biomechanics.

 

Ian:

I, of course, have the patient come in three times a day for a week so I can make sure my measurements are "accurate".....NOT!!!

I am not doing scientific studies in my office. I am doing clinical measurements that allow me classify feet into basic types so that I can compare the limbs to each other and to other patients. We all know that these measurement are not perfect, have variability and can have errors. However, I could certainly argue that the alternative that you suggest, of not making any measurements, doesn't allow one to fully appreciate the small structural varations in the patient's foot and lower extremity that would otherwise be missed.

Since you don't take measurments, Ian, then how do you assess patients for their biomechanical abnormalities such as limb length discrepancy, malleolar torsion, ankle joint dorsiflexion, etc???

 

Hello Kevin

Thanks for answering the question about measurements. I'm assuming by your opening paragraph that you acknowlege the impact of diurnal variation. So if the clinical assessment you make at one time gives you the values (whatever we may think about accuracy) for that time and you make your prescription based upon the values at that time. Your device comes back, fits well and the patient begins to experience improvement.

Allowing that there could be at least three different times when joint rom is different when you take your measurements ( which is fine as your choice of working) is there not a arbitrary nature to this "success". Someone could repeat your approach at a later time of day and come up with different values, apply different postings and achieve the same success.

To address your query about ankle dorsiflexion etc. I did actually indicate that I check for available roms in the various joints. I do not use a goniometer to measure angles of dorsiflexion at the ankle. Certainly in observations made by David Holland and myself we would argue that most people we assess have less than 10 degrees of dorsiflexion and have begun to consider this to be a common almost "normal" ( if I may use this word) occurence. If this is the case then it may raise the question of whether there is actually a "condition" called ankle equinus. The question that arises could be what then are we doing when we measure this?

In terms of Leg length difference. My experiences of working with physios suggests there are a number of ways of assessing this but that real accuracy requires X-ray (please correct me if I'm wrong) and that anything short of this has, as you say "errors".

 

Measurements

I have to agree with Kevin. Biomechanical measurements of the feet and lower extremities are somewhat a necessary evil, and if nothing else, provide us with 1.) a way of classifying foot types and the "degrees" to which they vary; and 2.) provide ways of communicating amongst ourselves and with orthotic laboratories.

Quote Ian:
"In terms of Leg Length Difference (LLD). My experiences of working with physios suggests there are a number of ways of assessing this but that real accuracy requires X-ray (please correct me if I'm wrong) and that anything short of this has, as you say 'errors'."

In our Clinic and Laboratory, we use many clinical ways of assessing limb lengths:

1. With the patient sitting (legs extended and supported, feet dorsiflexed) we compare the relative lengths of the legs by checking how the plantar aspects of the heels and the medial malleoli relate.

2. With the patient lying supine, we do the same as above.

3. With the patient lying prone, we do the same.

If we suspect a Leg Length Discrepency (LLD), we'll then measure the limbs doing:

4. Apparent leg length measurements with a Tailor's tape measure - measuring from the umbilicus to the same point on each of the medial malleoli.

and

5. True leg length measurements with a Tailor's tape measure - measuring from the anterior superior illiac spines of the pelvis to similar points on the medial malleoli.

6. Check posture (front and back); i.e., for shoulder droop/drop (often on the long side), hip elevatus, etc. .

7. Checking gait for limp, unsteady gait, more pronation one side vs. the other, etc. .

To confirm our suspicion of a LLD, (and you're right, it's the most definitive way) we'll then order scannograms (sometimes spelled scanograms). In the good old days, these were flat plate X-ray studies done with the patient lying supine with a metal tape measure placed beneath their leg from pelvis to heel. Spot X-rays were then taken of the hip, (of the knee if you'd like to know at what level the shortage occurs), and of the ankle. The radiologist would then calculate the leg lengths on X-ray; however, for some of them, their math (adding and subtracting) was terrible - so it was always best to check the films yourself and do your own math!

Nowdays, the radiologists use CT and let the computer measure the leg lengths for them. I still prefer the older method (but have gone along with the times) but think the results/answers I got were much better using the old X-ray method.

In any event, checking for LLD, in my opiinion, is one of the most important exams/evaluations I do as a practitioner (it's where I start actually); and I wish more folks in ALL of the disciplines (especially orthopedics and chiropractics) would pay more attention to LLD's!

Oh yes, I failed to mention that we also have the Radiogogy Department take an upright scoliosis view at the time of the scanogram study. A repeat upright scoliosis view with an appropriate amount of elevation/lift beneath the heel on the short side will often show immediate reversal of a pelvic tilt and/or amounts of any scoliosis that might be due to the LLD. Sometimes, what looks like a LLD, clinically, is actually primary scoliosis causing a functional LLD - so the upright scoliosis view is also helpful in these regards.

There may be nothing new to you here, but thought I'd share my ideas on LLD for those who haven't paid that much attention to this entity in the past!

 

"Planal Dominance"

 

The point is that you do measure or estimate ankle joint dorsiflexion still, Ian. Whether you use an instrument for increased accuracy or "guesstimate" a range of motion or deformity, what you are dong is making classifications of foot and lower extremity structure that are dependent on some form of measurement.

I am not of the belief (like I was taught at CCPM by the biomechanics faculty that taught STJ neutral position theory alone) that orthosis treatment should necessarily be based solely on measurements and ranges of motion. An important concept in using the tissue stress model of treatment is to identify the specific structural component of the foot and/or lower extremity that is injured, determine the nature of pathological forces/stresses that are causing the injury (i.e. compressive, tensile, shearing or torsional), determine the structural or functional parameters that are most likely causing the pathological forces to occur and, finally, determine the therapeutic methods that will be best at reducing or eliminating the pathogical forces on the injured structure, so that more rapid healing may occur (Kirby KA: "Using the Tissue Stress Approach in Clinical Practice", April 2002, in Kirby KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, AZ, 2002, pp. 17-18).

Since abnormal structure is more likely detected by measurements, then I advocate using measurements and logging them onto a data sheet so that the clinician can have a more complete appreciation of the biomechanical makeup of the patient's feet and lower extremities. This very importantly includes an assessment of the spatial location of the STJ axis, which can be done by measurement or by estimation, and a gait examination.

 

No question about it!

No question that other factors such as body weight, foot type, intensity of physical activity, etc. are also other causative agents that lead to pathology.

But how many people/patients do you know, Kevin, who have perfect "rectus foot types"; i.e., those who possess the Biophysical Criteria of Root, et al. which would lend their feet to optimal functioning on flat surfaces?

I'm pretty sure that each time you conduct your bioexam and take your measurements you find certain amounts of STJ/rearfoot varus and forefoot deviation(s). By now, if you've been paying attention to the positions, motions, and numbers, these feet you're examining must all start to be looking pretty similar - to the point that you ought to be able to characterize and classify feet into certain general "foot types".

All we're saying is that "as a result of our inherent and residual foot morphology, hard and flat surfaces are (for most people) the common pathological denominator to which ALL feet (regardless of foot type) must compensate, conform to, and function on most of the time, unless of course they're rectus! Show us the rectus feet!

The sooner we start being more honest with ourselves and others (including patients) by telling them that "there's really not that much wrong with most peoples' feet except for the fact that feet are not particularly well-designed to function on modern societies' hard, flat surface", the better off everyone will be! Perhaps even shoe manufacturers will begin to recognize the error of their ways and start constructing soles for shoes that are better suited to the actual morphology of peoples' feet.

 

Hi DrLCT2.

You said
"The sooner we start being more honest with ourselves and others (including patients) by telling them that "there's really not that much wrong with most peoples' feet except for the fact that feet are not particularly well-designed to function on modern societies' hard, flat surface", the better off everyone will be! Perhaps even shoe manufacturers will begin to recognize the error of their ways and start constructing soles for shoes that are better suited to the actual morphology of peoples' feet."

I couldn't agree more!

Cheers,
davidh

 

Fellow biomechanists and podiatry educators

Skin lines are dodgey (colloquialism for unreliable).

The two things a scientist would look for in quantification are validity and reliability. Published studies on the validity of skin lines suggest significant error exists which makes the measurement completely unreliable. Some authorities would suggest, 'eyeballing' is more accurate, but that is fraught with problems too. E.g. parallax error. When it comes to measuring subtalar movement it might be more accurate to register internal and external rotation of the knee (transverse plane) or adduction and abduction (frontal plane).

Using skin lines in the clinic to measure the range of motion of the stj would scientifically be the equivalent to taking an apple, a tennis ball and a soccer ball to represent the spacial relationship between the Earth, Moon and Sun, as one rotates around the other, then plan a space shuttle pathway. Not a good idea but the metaphor does cognitively register the point being made.

Reliability
Intra rater reliability is better than inter rater reliability according to statistical analysis and this supports Kevin’s earlier posting. The more often you repeat the exercise the lower the standard deviation.

The dilemma, which faces all teachers of biomechanics, is making the concept of movement concrete in the learner's mind. Drawing skin lines has that function and whilst artificial gives an appropriate example of temporal and spacial relationships. The range of motion is so small as to be impossible to measure accurately by this means but the visual display, illuminates. This is a good practical class exercise as an introduction to joint measurement and examination and should be part of a quantitative project to underscore inter and intra rater reliability as well as repeatability and use of instrumentation.

Drawing lines on patient’s legs also gives positive biofeedback to the client and provides a bookmark for kinetic analysis, such as eyeballing or video analysis. It has to be borne in mind however, in terms of a yacht's navigation, the skin line would equate to a bhoy in rough seas.


What say you?

Cameron

 

Dr LCT2,
You wrote
"But how many people/patients do you know, Kevin, who have perfect "rectus foot types"; i.e., those who possess the Biophysical Criteria of Root, et al. which would lend their feet to optimal functioning on flat surfaces?".

I don't think I've seen any, either in clinic or when carrying out research on "normal subjects, in 34 years since qualification (my God, has it really been that long Cameron ?

Cheers,
davidh

 

Hi Kevin

My apologies in not replying to your last proposals. Firstly I was having a break, secondly, I cannot find it now! I remember it was to do with foot positioning affecting the amount of possible varus we feel to see.

Perhaps I can put simply where I have currently arrived, not in terms of scientific approach as I am not trained in that manner. These are opinions arising from my own observations and from discussion on this site (thanks Craig). In brief:

1. I regard the more natural, non-weight bearing rear foot to be in a varus position in relation to the ground and leg.

2. The forefoot has the ability to assume varus and valgus positoning depending, amongst other things, on the neuromuscular development of the individual. It is not as controlled, nor possibly developed to be, by rearfoot action at this point. My experience and the way I have been trained to read the foot suggests that it is more common for the forefoot to assume a flexible supinatus with varied 1st ray positions. ( Again this only is my experience. Like you I have seen thousands but, really, numbers are not part of it because we are not dealing with a norm but what is natural to an individual and their nueromusculoskeletal intelligences and its information transfer). Of course there are issues of coalition etc but that is a different conversation.

3. Casting will find me going through the range from a neutral position or to a pronated position or to a derotation of the forefoot, any of these, as I'm sure we all do. The decision is determined by what the patient and I wish to try and achieve.

To address your comment on how we read the foot at this point. Yes, I agree, if you read the foot from slightly below STJ neutral then the amounts of varus foot types can and probably do change. This is not the same as allowing the foot to find its own position non-weight bearing and read it from there which is where I would start.

4. When it comes to devices then I apply my complementary medicine hat. A general, simple truism in the holistic field is that "less equals more". (I am aware that this is not always the case and there are times when more determined interventionist approaches are needed).

5. Weight bearing, I consider that the more natural position for the rearfoot to function is below what we currently call STJ neutral, within a small range of pronation. A range that allows something of a windlass affect to occur but not necessarily a full return to an assumed vertical position. I suspect the arrival at this assumed position is related to a consistent, uniformly hard flat surface ambulation thinking and may not be wholly applicable to walking barefoot on more natural surfaces

5 When it comes to devices, because of the above I do not use rearfoot posts to try and gain the vertical alignments weight bearing. By pouring the cast vertical I invariably find that, when weight bearing, the person usually has a rearfoot that is slightly pronated. On the whole I do not want to see a vertical heel in relation to the ground or leg.

6. I have always gone for a simple forefoot balance platform. Occasionally addressing the full forefoot angulation I have seen, or, sometimes keeping it to an absolute minimum. (this latter has worked exceedingly well). Where the physical needs of the patient allow keeping of intervention to a minimum (more frequently than we sometimes assume perhaps?) it has worked very well on the whole.

Is that because of the device – ultimately who knows? But there has been a change, apparently to the better.

7. When requiring some form of firm rearfoot control I have gone for medial or lateral heel skives rather than posting. What is interesting for me is when walking barefoot on natural surfaces I find the potential for the foot to become more unstable rather than stable (it may be my lig laxity mind you). At this point the foot seems, on the whole to adapt itself to produce a good platform. One way it can do this is that for a moment a piece of the ground or tuft of grass provides a momentary heel skive affect or the equivalent of a 1st ray cut out etc.

I understand to a degree the essence of your arguments regard neutral positioning and reading the foot in a way that reduces the amount of varus people claim to see. However, this, to my mind, is a significant move away from much of what has been taught (only natural as knowledge develops) but is unfortunately still often taught as the biomechanical truth at least here in the UK.

More significantly for me, if we have moved away from the traditional method (where measuring joint angles against an assumed norm is pointless any way, as the values are not consistently accurate through a day) where would we measure from now and again what?

Our knowledge of the complexity of the foot and its actions should not be equated with a need for complexity of intervention and herein lies something of the heart of struggle for me. The pursuit of an ultimate norm or definitive understanding in foot mechanics is not a search for the Holy Grail but more an attempt to build a folly.

Ian

 

Ian:

Thanks for the lengthy reply. My main point, which I don't believe you answered, is that you said that the "natural" position of the foot was a varus so that walking on hard, flat surfaces caused most of the pathologies we see. Isn't that a fairly accurate paraphrase of what you and others on this list are saying??

Now, let's imagine a hypothetical scenario. Consider that you totally forget about the idea that the STJ neutral position is "normal" or "natural". Imagine that you were trained by another type of non-Rootian foot specialist that didn't indoctrinate you to believe that the STJ neutral position should be your reference frame for bipedal human locomotion. Instead, this other type of non-Rootian training told you that the normal or, as you like to say, "natural" position of the foot is the maximally pronated position of the STJ. Your new training taught you that the STJ neutral position was inherently unstable and the STJ maximally pronated position was a better, more "natural" position for STJ function since many more people walked this way than in the STJ neutral position. In addition, you were taught that the STJ maximally pronated position was an inherently more stable STJ rotational position than the STJ neutral position.

In order to now evaluate a foot, instead of holding the STJ in the neutral position, this training will have you evaluate the patient's foot by maximally pronating both the forefoot and rearfoot while the patient was either lying prone or supine on the examining table. Then, the examiner is trained to measure the degrees of "valgus frontal plane deformity" of the plantar metatarsal heads relative to the patient's transverse plane.

How would then this new "frame of reference of foot function" change the perception that you and your colleagues that think like you (i.e. varus is common and its pronation accommodation to flat surfaces is bad) have in regards to the predominant or "natural" type of foot that the human population has??

If properly indoctrinated by this type of new, non-STJ neutral, thinking, then you may, after seeing thousands of feet, have come to the conclusion that the main problem with feet is that they have too much forefoot valgus when they are in the best functional or "most natural" position of the foot (i.e. maximally pronated STJ position). You also would probably conclude that the problem with the hard, flat ground is that it makes the foot become less pronated by supinating it toward the STJ neutral position, away from the more desirable maximally pronated STJ position. You would also believe that any movement of the foot toward the STJ neutral position, would be a poor position of function since you now believe that the STJ neutral position is an inherently less stable position than the STJ maximally pronated position.

Maybe this little story will help better explain why I think that your and your colleague's ideas that varus is natural and causes injuries because of its pronation accommodation to hard, flat surfaces could very well be the exact opposite view of what would be predicted by the alternative, hypothetical belief system outlined above where the hard, flat surfaces could be perceived as being bad because it didn't allow most feet to walk in its "more natural valgus forefoot posture" since the foot had to supinate to reach the ground!

This little bedtime story may also better illusrate why I made the statement:

 

Hi Kevin

Thanks for the lengthy reply. My main point, which I don't believe you answered

My apologies for not addressing your main point. Craig did post it for me after I had initially replied and mentioned I had lost the message thread after it had been split.
is
that you said that the "natural" position of the foot was a varus

Only to a certain degree Kevin. As I said in my reply, I consider the nonweight bearing, natural position of the foot to be that of rearfoot varus. That is, most of the times I assess, the foot sits naturally into a varus position in relation to the leg when left simply to hang. This would be my starting point. I happily acknowledge that the fore foot can adopt whatever position it wants from there but that my view is that it is in some degree of Supinatus on the whole. Not being picky, simply want to be as clear as I can.


so that walking on hard, flat surfaces caused most of the pathologies we see. Isn't that a fairly accurate paraphrase of what you and others on this list are saying??

I cannot speak for others here but not really. I think (?) I have come to continually emphasize that, for me, it is the uniformly hard, uniformly flat, non-contoured (naturally that is) surfaces that have a significant contribution towards pathologies. Not the fundamental cause. From my reading of material by you and Craig I understand more clearly your views that it is forces, not rotations that make significant contributions to pathology in gait. Because the foot on a man made flat surface ( as described above) adapts, essentially, to a repeated, almost the same regular shape those forces are repeatedly applied with hardly any chance to dissipate them by conforming to a different contour (albeit slight) in a different step.

This is very different to your paraphrase.

Today I walked on a pavement which has a lawn by the side (I live on the coast so have the typical local coastal layout of path and grass). I wore very thin soled shoes. Walking on the path my feet adapted to the same pattern of movement throughout. I walked the same length on the local authority lawn in thin shoes. I could feel the contours. My feet wanted to adapt to them but my shoes would not let me. In the past my bare feet have adapted there very happily and with each step have functioned slightly differently as described in previous posts. Certainly there are forces at work but not the same repeated effect. Perhaps, herein, may lie something of the combination of force and surface.

Now, let's imagine a hypothetical scenario. Consider that you totally forget about the idea that the STJ neutral position is "normal" or "natural". Imagine that you were trained by another type of non-Rootian foot specialist that didn't indoctrinate you to believe that the STJ neutral position should be your reference frame for bipedal human locomotion. Instead, this other type of non-Rootian training told you that the normal or, as you like to say, "natural" position of the foot is the maximally pronated position of the STJ. Your new training taught you that the STJ neutral position was inherently unstable and the STJ maximally pronated position was a better, more "natural" position for STJ function since many more people walked this way than in the STJ neutral position. In addition, you were taught that the STJ maximally pronated position was an inherently more stable STJ rotational position than the STJ neutral position.

I have no problem imagining that and have had discussions with bioengineer friends and orthotist friends about how the pronated gait (not maximally though I have to say, but happy to go with your illustration) may be a more efficient one.

In order to now evaluate a foot, instead of holding the STJ in the neutral position, this training will have you evaluate the patient's foot by maximally pronating both the forefoot and rearfoot while the patient was either lying prone or supine on the examining table. Then, the examiner is trained to measure the degrees of "valgus frontal plane deformity" of the plantar metatarsal heads relative to the patient's transverse plane.

How would then this new "frame of reference of foot function" change the perception that you and your colleagues that think like you (i.e. varus is common and its pronation accommodation to flat surfaces is bad) have in regards to the predominant or "natural" type of foot that the human population has??

Apart from your point in parenthesis ( which I have addressed above) I can readily accept that my perceptions would be different. Not necessarily any more wrong or right than anything now, but certainly different.

But we will have once again adopted a possible arbitrary position from where to measure? By rotating the pts foot from where it naturally hangs (what ever that may be to that individual) nonweight bearing we have applied an interventionist approach from which to begin measuring. Why not lie the patient prone / supine let the foot hang, see where it falls and go from there.


If properly indoctrinated by this type of new, non-STJ neutral, thinking, then you may, after seeing thousands of feet, have come to the conclusion that the main problem with feet is that they have too much forefoot valgus when they are in the best functional or "most natural" position of the foot (i.e. maximally pronated STJ position). You also would probably conclude that the problem with the hard, flat ground is that it makes the foot become less pronated by supinating it toward the STJ neutral position, away from the more desirable maximally pronated STJ position. You would also believe that any movement of the foot toward the STJ neutral position, would be a poor position of function since you now believe that the STJ neutral position is an inherently less stable position than the STJ maximally pronated position.

Maybe this little story will help better explain why I think that your and your colleague's ideas that varus is natural and causes injuries because of its pronation accommodation to hard, flat surfaces could very well be the exact opposite view of what would be predicted by the alternative, hypothetical belief system outlined above where the hard, flat surfaces could be perceived as being bad because it didn't allow most feet to walk in its "more natural valgus forefoot posture" since the foot had to supinate to reach the ground!

As mentioned above I can understand where you are coming from, hypothetically, and can certainly understand the pain of shift in unlearning and relearning.

Now, am I correct in assuming that common to both our views would be:

1. The significance to the role of STJ neutral may be over stated indeed almost unnecessary?
2. That the idea of having to come up to a full vertical heel via the windlass phase may not be necessary?
3. That posting to keep the heel as near STJ neutral as possible at certain points in gait may be at best pointless and at worst, possibly detrimental?
4. That these approaches, and possibly others, spring out an interventionist approach to correct what we have considered abnormal but in reality may introduce abnormality, in light of the above conversation?

If so, does what we teach biomechanically create more problems for practitioners in grasping it than it needs to? Could it really be an awful lot simpler?

Regards

Ian

 

Hi Ian,

You wrote
"If so, does what we teach biomechanically create more problems for practitioners in grasping it than it needs to? Could it really be an awful lot simpler?"


Well, I believe so!

Regards,
davidh

 

I am much more in agreement with your statement above than when we first started the discussion. It is likely that the repetetive nature of each foot strike on a flat, level surface does increase the likelihood that some pathologies will occur. However, to be fair, it could also be said that flat, level surfaces likely also improve walking efficiency and decrease the risk of catastrophic inversion ankle sprains and falls. Therefore, until we have some definitive research in this regard, it is purely speculative to state that flat, level surfaces are a predominant cause of foot and lower extremity pathology in today's walking human. In fact, one could just as well speculate, with an equal level of certainty, that flat, level surfaces allow improved metabolic efficiency of ambulation, helps prevent lower extremity traumatic injuries and reduces the risk of catastrophic falls in today's walking human.

This is not an easy question to answer without lengthy discussion. Suffice it to say that I consider STJ neutral is essential in communicating structural pathology of the foot in a relatively accurate and coherent fashion from one professional to another. I also consider the STJ neutral position to be the best reference position we currently have for a mid rotational position of the STJ. In addition, I think the STJ neutral position is a wonderful position to make functional foot orthoses around for the vast majority of patients. However, I would tend to agree that the significance of the STJ neutral position as an ideal functional position for all feet has been over stated. It is likely to be an ideal functional position for the middle of midstance of walking gait while in shoes with heels for over half the population but when these people walk barefoot, a position probably 3-4 degrees pronated from neutral position would more than likely be considered ideal for the middle of midstance. In other words, the timing where the STJ hits the neutral position during the latter half of stance phase of walking will be very dependent if the patient is barefoot versus in a shoe with either a small or relatively large heel.

I don't have any idea what the "windlass phase" is. Is this propulsive phase of walking?? In what reference is the term "windlass phase" used since I would like to see that reference?!

First of all, and very importantly, the heel does not have a neutral position. The STJ has a neutral position, not the heel. Maybe this is a slip of grammar but it is important in such discussions to keep the terminology precise to avoid confusion. The goal of orthosis therapy is not to "keep the STJ neutral" but to allow the foot to pass through the STJ neutral position at the correct times during gait. I believe that the optimally functioning foot has a constantly moving STJ during gait and never stays in any one STJ rotational position for a significant time during the stance phase of gait. Trying to push the STJ toward neutral position is not necessarily beneficial or therapeutic for all feet. For example, the foot with posterior tibial dysfunction (I saw two of them today) may function best with foot orthoses closer to the STJ maximally pronated position than in the STJ neutral position. But that discussion will need to be another thread for Craig to start.

The goals of orthosis therapy should be to 1) reduce pathogical loading forces on injured structures, 2) optimize gait function, and 3) prevent other injuries from occuring. If number 3 has occurred in the patient, and especially if the practitioner believes that nothing can go wrong with their orthosis thearapy, then orthosis therapy will commonly fail since it has "introduced abnormality."

However, on the other hand, a non-interventionist approach is based on the "lazy" concept that if it doesn't hurt, don't treat it. I do not believe in this approach, since, for example, orthosis treatment of pes valgus deformity in children is one of the most signficant things that we, as podiatrists, can offer to the growing flatfooted child that has significant abnormalities in foot structure and gait function. The orthodontic medical professionals certainly don't wait to mechanically correct tooth and jaw alignment in the growing child until a time in adulthood when the teeth are so crooked and the correction time is so prolonged that the individual develops permanent tooth and/or jaw pathology. Why do some podiatrists get so worried about treating children with foot orthoses since we are only using a nearly identical treatment philosophy as the orthodontist? This is especially comical to me when I consider the wide variety of shoe designs that these children wear every day without any complaint from the profession about the pathological mechanical effect that these shoes have on children's foot structure and function. Seems quite puzzling to me at times.

Biomechanics is much simpler, as long as it is taught properly. Using the STJ rotational equilibrium theory and a knowledge of the kinetics of the other major joints of the foot as a basis for the decision making process of treating foot and lower extremity mechanical pathology has allowed many individuals that I have taught to gain greater clarity of thought regarding foot and lower extremity biomechanics. I believe that you will greatly enjoy the chapter (Subtalar Joint Equilibrium and Tissue Stress Approach to Biomechanical Therapy of the Foot and Lower Extremity) that Eric Fuller and I wrote last year that will hopefully be published by the end of the year in a book by Dr. Stephen Albert. I think that as long as the podiatrist has a good understanding of basic physics and mechanics, they will find the chapter quite enlightening.

Ian, your comments and observations are some of the best that I have read in many months of discussions on this list. It has been a great pleasure to read your interesting postings and hopefully, someday, I would like to meet you so that we can discuss these matters over an adult beverage or two. Its my shout.

 

Hi Kevin

I've equally enjoyed them but don't mind admiting there has been a small mountain to climb as a non-researcher / non-scientist type person. For me, therefore, biomechanics has been as much about intuitive understanding combined with practical learning but always more loaded towards the intuitive. It's the way I learn.

You said:

"I would like to meet you so that we can discuss these matters over an adult beverage or two. Its my shout."

Could you throw in the airfare, accomodation, epcot centre visit, flight over the Grand canyon Hmmm, what else I wonder?!!! ( hee hee)

Cheers
Ian

 

Dear Craig,

My thoughts are very much on parr with yours from the days I started appling biomechanical assessment in private practice. Forces Primarily have to be the damage inflictors to the lower limbs. Add a person with large angles of deformity eg, Large Forefoot varus and genu varum for example/ patient overweight=more forces acting on already predisposed limbs).

Take a person with mildly poor(deviating from neutral) biomechanics, inactive (less frequent trauma to limbs) and if you are lucky they may end up with mild plantar fasciitis when old. Don't ignore that some people with high pain threshold block out pain. I see plenty of these with a mild symptom but when prodded for history they eventually own up other symptoms. Again they can live with it.

So I treat those with mild symptoms with premoulded orthotics, and severe cases only get Customised after a full biomechanical and gait assessment.

Yours Sinerely

 

Dear Craig

I wonder what you would make of this consideration of why we can't define normal feet.

Your original question was "what is a normal foot" and you conclude **"The normal foot is the foot in which the forces are below the threshold for tissue damage", which is the definition I would agree with. This may be because it has been beyond our ability to characterise the normal foot more precisely.
This is more evident when considering the foot of a subject far outside the norm in other aspects ie what is the normal foot of a CP child? I would say the one that causes no problem even though it is unlikely to represent the mainstream normal shape or function. However Can we define a normal foot without defining a normal person and how far outside the usual does a person have to be before they are not normal. Cameron says that perhaps if a variable, such as HAV, is present in 90% of the population it is normal. Is usual a measure of normal? If 90% of the population of Africa became infected with HIV is this normal? what if the population of Africa becomes immune to HIV? Are they abnormal because they have the potential to pathologicaly affect other populations?
So should a comparative study have 2 groups, 1 non pathological and the other pathological? (where the aetiology is biomechanical, which in itself may be difficult to define)
Is there a secondary problem of definition due to statistical limitations, flaws or ineptitude?
There will be many confounding variables and dependent variables to address. The significance of the former may be reduced with rigorous randomisation.
However the population standard deviation of just one dependent variable may have a wide standard error when characterised in terms of the sample sd. especially if the sample was small and did not have statistical power.
Many studies appear to make no effort at an a priori, or even post hoc, estimation of sample size and power. Therefore it could be the case that as the variability value of measured observations are high and the changes required for the foot to become normal (by the above definition**) may be very small, the sample size required to confidently reject the null hypothesis will be extremely large. So if one requires a p(alpha) 0.01 and a p(beta) 0.85 and there is a small standard difference then the cohort size may need to be hundreds or even thousands. Has a reliable sample size been established in any 'normal foot' studies? Is it possible that many studies have type 1 errors simply because they didn't have a large enough sample or the confidence levels were not suitable for the size of variation required to be measured.

Therefore the definition "The normal foot is the foot in which the forces are below the threshold for tissue damage", may be the safest and reduction of tissue stress/strain by mechanical means may be the best way to achieve this.

All the best Dave Smith

 

I disagree that the definition "The normal foot is the foot in which the forces are below the threshold for tissue damage" should be considered as the best definition for a normal foot. There are many obvious structural and congenital deformities that, if present in a foot, would preclude the average clinician from categorizing the foot as being normal, even though no tissue damage had occurred.

For example: How about the 16 year old patient with a severe juvenile bunion deformity that wears sandals all the time and has no pain or symptoms? Should this foot be considered to be normal? How about the patient that has a congenital shortening of the 3rd metatarsal with a floating 3rd digit but is asymptomatic? Should this foot also be considered to be normal? In order for the definition of foot normality to be inclusive of the criteria that clinicians commonly consider for this determination, one can not just consider the presence or absence of tissue damage alone, one must also include obvious structural or congenital deformities within the foot that may be asymyptomatic due to lack of tissue damage.

Maybe we can have a little discussion with Craig and others on this subject while in Belgium.

 

Kevin

I can agree with that in terms of anatomy but in terms of biomechanics I think the definition, "The normal foot is the foot in which the forces are below the threshold for tissue damage", can still hold since if the deformity is such that it can lead to pathology then the forces in the foot are not below the threshold for tissue damage to occur.

What would you say about this analogy?--

I take a catalogue from each of a hundred randomly chosen chair manufacturers and randomly choose 10 models of chair from each catalogue.
I measure all the parameters, height, width, cushion thickness and durometer, arm length, number of legs, etc, etc, etc. I produce distribution curves for all these parameters and find the mean and sd for all. Does this mean that any chair outside the 2 x sd for instance is not normal? Must all these chairs be altered to be within normal parameters? Are those chairs still functional and comfortable as they are? Does any chair made actually fit the normal model exactly?
What if the mean number of legs are 3.7 - does this mean a normal chair should be wobbly? Will a Normal chair be suitable for every purpose?

All we can really say when defining a normal chair is that it is stable and comfortable and fit for the purpose for which it is used.

So could *Normal in these terms mean useful, non problematic and fit for purpose.

Perhaps I should have compared *Normal chairs (group A)to chairs that do not fit the *Normal criteria (group B) but then the problem is deciding which chairs didn't fit that criteria. Because before I started I didn't know how to properly categorise the chairs, so I used a nursery chair to sit and watch TV. It wasn't comfortable for very long and eventually it broke (I weight 100kg). So I put that chair in the Group B. What if that chair fitted within the range of sd previously used to indicate normality? Does this mean that normal chairs can be abnormal when there are confounding outside influences.

Can a person, of 160cm (5' 5") tall and weighs 120kg (265lb), who has painful feet also have normal feet? Or even - Can a person who has normal feet also have painful feet?

How confusing and difficult is it to define a normal yet simple chair. we are trying to define a far more complicated entity in terms of normal. Obviously it will be difficult and perhaps not very useful.

All the best Dave Smith

 

Dave:

Are you now going to try and predict the future with your definition by saying that an abnormal foot may have a deformity that "can lead to pathology"?? This would be a big mistake for any definition of a normal foot, I believe. Can you predict when and which anatomical structure in a normal appearing foot will have an injury? If you can then you are a better clinician than I.

Even though I somewhat understand your analogy using the chairs, we are not talking about inanimate objects that are manufactured, we are talking about a living entity whose structure is controlled by their genetics. As such, gross genetic abnormalities are considered abnormal in most cultures even though these same genetic abnormalities might never lead to "tissue damage".

A better definition of normal, I believe, was offered by Root et al over 35 years ago:

The one critique of Root et al's definition, which I believe is much better and complete than the definition, "The normal foot is the foot in which the forces are below the threshold for tissue damage", is that it lacks any mention of existing congenital abnormalities which any reasonable clinician would consider to be abnormal.

David, if a patient presented to you with seven toes (i.e. supernumeraray digits) and this patient was not having any pain from these extra toes or had no signs of tissue damage, would you then consider this foot normal??

Here is Microsoft Encarta's first three definitions of normal:

Certainly having a few extra toes on a foot would not be "usual" or would not be "conforming to the usual standard" even though the patient with those toes may be "physically, mentally and emotionally healthy" and even though these extra toes did "occur naturally".

If you want to make an improved version of the definition of a normal foot, I would suggest start with Root et al's more complete definition, reword it to include Craig's suggestion of tissue damage and then also add in a section that acknowledged that congenital abnormalities may also preclude the foot from being considered "normal".

Interesting discussion.

 

I would add to the encarta definition of "normal" which Kevin posted it's use in mathematics to mean perpendicular. This fits very well with Mert Root's normal.

 

When we properly survey some feet in all age 'groups', find the mean foot without any history of lower limb pain or physical(normal) deformity which could lead to symptoms as person reaches next age group, we may once again find out the normal foot specifications. Physical deformity (even extra toes/HAV etc) shows tissue changesor extra tissues present, which could become symptomatic in later life,yes?!

Let/s make sure we are stringent in history taking and biomechanical assessments though! Who wants to do this study?? Please make sure your findings are based on at least as many subjects as the medical profession would consider a viable study, not that I always trust their conclusions either.

 

Thank you all for this thread posted originally in August 2005 by Dr.Kevin Kirby.

I have searched the internet for this particular book without success.

May I ask is anyone aware of suppliers?

I sit, stand, fall down agog with appreciation to all the great minds who have contributed to this thread.

Thank you. :good:

 

The editor of the book passed it on to someone else to finish. Thanks for the reminder to look into it and I will give the folks who have it now a push. If they don't get it done soon, Kevin and I will have to look for a new place to put it.

Eric Fuller

 

Thanks Eric,

I would be grateful if you would keep 'us' posted.

Regards :drinks

 

Kevin and all

Kevin wrote

I believe this quote and the post accompanying it fits quite well with a post I put on another site on the same question'

Regarding Normal -

We use Normal when we should use the term Reference. EG the Normal Position is actually the Position of Reference.
The human cannot live without reference systems we need temporal and spatial and social reference, we cant live and function 'normaly' in the moment we must have reference to past and future, we cant be somewhere without knowing where somewhere else is.

Everything we relate to needs a reference EG is your life 'normal' chances are you will say yes Is your life the same as Derek's or Bill's and do they have normal lives. What are your references for your 'normal' life? How far outside those references would someone have to go to be abnormal in your view? Does their life then function in a pathological way? Would that be a matter of opinion. What would be the difference between this example and a 'normal' foot?

If you were to change the point of reference does this make the previously 'normal' into 'abnormal?

If you were to compare Derek's foot to Bill's, and assume that there you are both asymptomatic, would you expect that you both have identical feet and that the foot parameters in terms of posture index or dynamic function, would be the same? Unlikely, yet they both may be 'normal' at what abritrary point would a foot become abnormal. There is none.

Forget 'Normal' there is no such thing in terms of a tangible measurement that we would like to attach to it.
We should instead think " Does this cause us concern" if so then "what can we do to belay this concern"
If you want a definition then 'Abnormal' causes us concern and 'Normal' does not. Where this concern begins and ends is entirely philisophical empiricism. (probably)

In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience, especially sensory perception, in the formation of ideas, while discounting the notion of innate ideas. (Wikipedia)

Cheers Dave