New goals for Podiatric Biomechanics

Not sure I agree withthat Craig. As I wrote in the first post in the recent thread on Ethics...

Certainly the UK has a unique perspective given the historical varied training routes - something not evident in Oceania and USA - but there is a tacit acknowledgement in favour of the preceding statement.

 

Yes, there are still leaps in logic and inconsistancies. There are two definitions of normal. The biophysical criterea for normalcy and essentially a tissue stress approach. Paraphrased: normal is the absence of pain when the person goes about there daily activities of living.

How does an orthotic work. Again multiple reasons 1) It holds the foot in neutral position. (discussed already) 2) It supports a forefoot deformity. The forefoot deformity is measured in neutral position, yet even Mert Root and Bill Orien said that 60% (Mert) to 90% of feet stand pronated. In a preliminary study I did 30 of 30 subjects stood within 3 degrees of maximal pronation. So you are measuring forefoot to rearfoot relationship in a position that is not the same as which the foot is in when standing. The forefoot to rearfoot relationship changes with STJ motion of the STJ.

There are more.

In other parts of the discussion there was talk about not being able to discard existing paradigms. The distinction needs to be made between observations and theory to explain those observations. For example, Root, Orien and Weed, describe the partially compensated varus foot. This is an observation. There are some feet that don't have the range of motion to evert the foot enough to fully load the medial forefoot when the person is standing. Another observation is that some of these feet feel better when standing on an orthosis made from a neutral position cast of the patient's foot. A theoretical explanation of this observation is that the orthosis holds the foot in a more supinated position. I can't dispute that some people feel better. However the explanation is disputable.

Eric Fuller

 

Tissue stress simplified

The tissue stress approach:
Identify the injured structure. This should not be new or different from what you have been doing.

Find a way to reduce stress on that structure. Here is where the mechanics comes in. You do not have to calculate the magnitude of force within that structure, you just have to know what modifications need to be made to reduce stress on that structure (crutches?! and more).

Re-evaluate and modify depending on the initial response to symptoms.

You could develop a list of modifications for each pathology if you wanted to make it really simple. However, you may miss some of the interactions, but this is a good start. One promenent orthotic lab has developed pathology specific orthoses. This is generally a good idea. However, I feel that knowledge of the location of the STJ axis is critical in making a decision on what modifications you want to make. You can have STJ pronation related problems with both a medially and laterally deviated STJ axis. This is because there is more than one source of pronation moment. High pronation moments can come from ground reaction force or it can can come from muscles. People with medially deviated axes will have pronation from ground reaction force and people with laterally deviated axes will have pronation from musclular sources. For example, you will see plantar fasciitis in both people with laterally and medially deviated STJ axes. So, if you always included a medial heel skive when whenever you saw plantar fasciitis, it would be wrong for some patients. I can't think of too many other surprises in the tissue stress aproach. Although the problem of "does the pain cause the gait or does gait cause the pain" issue comes to mind. Therefore, address the anatomical structure that hurts rather than address what you see in gait.

There it is, the tissue stress approach in a couple of paragraphs. Any thoery worth its salt should be able to be boiled down to a couple of sentences. I recall the quote of some King when he had the solar system explained to him by an "Earth is the center of the universe" scientist. "If I were god I would have made it much simpler." There had to be many exceptions and modifications in the theory to fit the observations, so the theory became incredibly complex. The tissue stress approach is not that complex.

Cheers,

Eric Fuller

 

Craig

Biomechanics in the UK

Until the 80s, few practitioners in the UK had heard of biomechanics and it was really a lay term with bioengineering thought to be the prime discipline. Biomechanics had been used by medicine since the 18th century to describe a body system but became more associated with musculo-cutaneous/neuro-muscular activity in North America. Foot Appliance (orthoses) making in the UK was not as clearly registered as other orthotic and prosthetic works and was a no mans land which chirpodists like Charlesworth developed and eventually took to the States. Arch supports had always been an enigma but were promoted through companies like Scholls who supplied foot requisties OTC. They rose to prominence in the 30s when post depression there was a great up surge in marathon activities from dancing to skating to running (Look up Bunion Derby). Little or no scientific work had been undertaken as to how these devices worked. There was just a general acceptance they did.

When Inman came up with the gait cyclce then several people began to consider foot function with Root et al the most prominent in the states. The 70s saw a change and foot orthoses in North America became more respectable. In the UK there were also pioneers but to a lesser extent. In the UK, the NHS continued to not restrict pods from supplying foot appliances Approximatley7% of the pod population used appliances up untilquiterecently. Interest was kindled to include LA into base line practice in eartly 80s but because of the orthopaedic objection, post grad groups brought in podiatric biomechanics which was driven and supported by commercial labs. The theories eventually filtered into the training syllabi of the schools in the UK Big crisis for the tradional appliance makers to come to terms with the new theories but this also coincided with a new order of young pod seeking postgraduate academic qualifications. Biomechanics (bioengineering) was attractive and that generation influence what would take place later ie a new specialisation requiring moretraining . Aussie and NZ meantime had a similar exposure to the tradional appliances and the North American influence but with a different podiatry patient interphase which favoured private practice geared to elective and niche care for groups with medical insurance and or disposable income. (Rare commodity in the UK.), then foot orthoses and the Root theory became main stream syllabi in the devloiping univeristies until the new crop of academics began to question the scientific basis which started with Bob Kidd . Dr Kidd as you know was one of the new kids in the Uk to look at the academic basis for the new theories.


Cheers
Cameron

 

To add to Eric's nice summary, the tissue stress approach is not all about evaluating STJ axis moments but is also about considering the longitudinal arch flattening moments (i.e. forefoot dorsiflexion moments) acting on the foot during weightbearing activities. Plantar fasciitis and dorsal midfoot interosseous compression syndrome are probably caused more by increased forefoot dorsiflexion moments than they are about medial or lateral STJ axis deviation. If you know the functions of each structural component of the foot and lower extremity, and you know the particular structural component that is symptomatic, then designing an effective treatment plan is not all that hard.

I like to think that I am "viewing the internal forces of the foot and lower extremity" when I am considering how a patient stands and walks and/or runs. In this way, then, I am always focusing my attention on determining the pathological mechanical force that is causing the pain so that I can determine the best way to reduce the pathological internal force and make the patient better.

Is this that complicated? Maybe I think it is so simple since I have been practicing this way for over the past 20 years?

 

I'm working on it...

These basic concepts are ingrained and tacitly acknowledged without ever being vocalised per se. You can name all the muscles, their actions origins and insertions, you can memorise the pathomechanics of a corn, you can tell patients their blister is a result of shearing stress but to apply these as a unique assessment? There is no such thing as an easy answer. I apologise for my frustration and thank you for your patience in explaining this to me.

 

Footfan

You said "there is no such thing as an easy answer."

To some of the questions as to normal foot and normal foot function maybe not.

But intervention into a biomechanical foot problem is not dependent upon such answers and is often remarkably simple. The two should not be confused with each other. When it comes to intervention, simplicity generally works for me very well.

Ian

 

I am only new to a lot of the material presented here but I tend to approach this statement with scepticism. I am a huge advocate of understanding the interventions we use, I like to know what I intervene with makes sense and I sleep a lot easier knowing why it works - also makes that dreaded question (from a patient) 'why do I have to do this' a lot easier to tackle. I guess that's why I'm here and continuing to digest this information even though it can be a tough slog sometimes (ok most times).

Perhaps the intervention is remarkably simple but maybe the problem is we don't understand why it's simple and may be making things a lot worse, almost like prescribing a drug without knowing the side effects? Then again, maybe I am making a mountain out of a mole hill and should slide back into blind trial and error, I have been thinking this over so much I am confusing myself.

 

I would approach the statement with similar sceptism. I used to be accused of being an "academic" and not a clinician, maybe this was true. But now that I'm a clinician and not an academic I use all of my academic knowledge to enable me to treat patients better. This is why I have a thriving practice and receive referrals from other podiatrists, and why other podiatrists bring their own children to me for care.

My advice to you foot fan is to go back to first principles: know your anatomy, know your functional testing, know your theories, understand applied physics, be a dab hand at orthoses manufacture and you will start to glean an understanding of how to plan your interventions so that when asked you can give a reasoned answer to your patients.

In short, being an academic makes you a better clinician, but being a clinician alone often leaves you in the dark. But just because you have the book on your shelf, doesn't mean that you understand the content.

In terms of theories: paint with all of the colours all of the time. If you only use one, then you paint in monochrome- arty, but somewhat limited

 

Truly, a clinician may also be an academic. I would consider a clinician that has proven their worth in academic areas, such as published research and lecturing at seminars, to be an "academic-clinician", which is the label that I would choose for you, Dr. Spooner.

I guess this label is not too bad for a former punk rock band member. But the bigger question is, can you still do the pogo? http://video.google.com/videoplay?docid=5274458942932280461

 

Top draw animation kevin, but where is the shouting, sweating, swearing and punkish behaviour? These boys wouldn't have made it into my band

 

Hi Foot Fan and Simon

I agree indeed that many and possibly all theories to do with podiatric biomechanics should initially be greeted with suspicion. Part of the problem in the past is that they were possibly not greeted with enough!

In the courses David and I run we actively encourage suspicion and scepticism, even of our own approach. When people then go on to ask how soon can they do module two we generally suggest they first take away what they have learnt, apply it and if it worked for them then get back to us and look at module two.

My reason for suggesting that intervention is often far more simple than the theories that surround it is based upon years of podiatric practice and manufacturing experience. It is also based around our perception of least intervention (generally speaking prescribe according to what you see on the cast and not the foot. A vertical heel with a 2 degree forefoot post medial or lateral will see a substantially large proportion of pts go away very happy). It is only the more unusual cases that get something very different.

BTW I leant my manufacturing approaches and some of my thinking at the feet of bioengineers rather than pods. Thankfully they pointed to the huge inconsistencies of podiatric approaches to biomechanics many years ago.

Simon. I agree with you about A & P stuff but you then said: "In short, being an academic makes you a better clinician, but being a clinician alone often leaves you in the dark."

I cannot agree with that statement.

There have been academics who have proported flawed biomechanical theories and gone on to teach about prescribing from the basis of such theories. (according to Kevin, elswhere, there are some that still do). Does that equate to being a good clinician? There are clinicians outside the world of academia who have ditched tradditional approaches and prescribed according to their own understanding, often successfully, they may lack academic qualification but they are biomechanically astute, intuitive and intelligent.

As to referals, I and many other none academics have enjoyed just the same without a Phd (no derision meant by this I would not be pushing myself the way I am if I did not think education important).

Ian

 

yeh, whatever. If you read what I said, it was "better clinician" not good.

What I find interesting is that while you now need to be registered in the UK to call yourself a podiatrist, anybody can run courses without any obvious qualifications or quality assurance.

 

Hi Simon

How do you define quality? The material provided, the way it is delivered, the ability of practioners to go on and do what they have learnt after the course? Over the years I have attended many courses of supposed "quality". Run by companies, and run in hospital departments, lectures provided by key biomechanical "specialists". Fortunately I have been able to sift from it that which works for me and go on but many of the people attending with me (much brighter than me) have not. Their fault? Poor delivery?

Are qualifications to be academic or practical? Both?

What of the people who have trained at university and come onto the site and still argue that it is confusing. Are they not getting quality deilvery by the very qualified people?

I am not opposed to academia or expanding knowlege. I just never have believed, and my own life experience has shown me, that the ability to teach and give practical ability lies soley in the hands of trained teachers or academics. They have their role but they are not guaranteed purveyors of knowlege or quality practical ability.

Ian

 

How did I know that this would be the response- no brainer! If you knew anything about quality assurance in education you would not have given this response. Yet you are clearly putting on courses... So you must know all about that. Right?

But hey, as long as it works for you, we can keep pushing interventions which lack evidence and understanding then?
http://news.bbc.co.uk/1/hi/health/5007118.stm

Another no brainer response, here's my answer: both, I like to learn from experts in their field and those who have a sound understanding of educational theory (usually both of these qualities at once). From your writings here, and apparent lack of writings were it counts, you strike me as possessing neither of these qualities. I could be wrong though, so here's your opportunity to show us your CV.

Ah, the good old university of life. Guess what? Everyman and his dog got that degree, in the competitive market place which is post-graduate education, you may just need a bit more than that to bring in the crowds and have em leaving happy. Good look with your courses and for that matter your future "life experiences". Unsurprisingly, I will not be attending either if I can help it.

I'm sure though everyone would like to learn about your new theories of biomechanics and clinical therapeutics. But if its all about how the foot didn't evolve to walk on a hard flat surface etc etc which we've heard from your co-conspirator in the past, we can shoot it down in flames. The stage is yours, play on.......

 

Simon

I do not claim to have a CV to display in front of people indeed I have made it clear where I come from. Nothing to hide about this and, for me though I strive to improve, I feel to have nothing to prove.

The derogatory implication that I was relying upon the "university of life" is far from a position I take, as I have made clear in my posts suggesting that I look to improve my academic ability. BTW, I actually have no problem with the university of life as it has served me well.

With regard to "No Brainer" responses and the tone of them I find myself predictably disappointed.

In terms of quality assurance in education I cannot comment. I am not ashamed to openly admit I am not a trained educator, which ( I think) I have never claimed to be. As to whether I enable people to learn and practically apply the skills, I am comfortable with what I achieve and work to improve all the time. So far as I can tell, at the moment, people have not found it disappointing.

Certainly David and I hold similar views, which you make clear you are not interested in. Interestlingy I do not find your responses to him carrying the same acid tone.

You said "Good look with your courses and for that matter your future "life experiences". Unsurprisingly, I will not be attending either if I can help it."

There is much I could say in response to this phase but I think so much of what lies behind it stands out for itself.

Polite regards

Ian

 

Just ask my wife what impact I, as an 'academic' has on improving the clinical outcomes in her clinic.

 

Simon,
You said:
"But if its all about how the foot didn't evolve to walk on a hard flat surface etc etc which we've heard from your co-conspirator in the past, we can shoot it down in flames. "

Co-conspirator?

Anyway, I've been suggesting for years now, here and on Jiscmail, that we haven't evolved for life on a hard, flat surface (only approximately hard and flat, I agree). I've found it's a great way to get ignored

Please, please give me a reasoned argument as to why you think we may have evolved for life on a hard, flat surface.

Not holding my breath.....


Cheers,
davidh

 

Yet this makes perfect sense if
a) we view forefoot anomilies as "normal" (ie present in most of the population, which they are. Your pilot study, and my own study in over 100 "normal" subjects show this to be the case. Any doubters out there only have to examine a few feet.....) - and -
b) an orthosis does little more than balances or stabilises the foot for support/ambulation on a hard and flat surface. An orthosis posted to 2 degrees FF-only does this pretty well.

Thank you for answering. I've been away and am only catching up now.
Regards,
davidh

 

From reading your postings over the past few years David, the central tenant of your argument appears to be that much of the pathology we see in the foot is due to the fact that we didn't evolve to walk on a hard flat surface and that we now spend much of our time doing just this.

The problem with your theory has nothing to do with evolution it is that the surface we walk on for much of the day is neither hard nor flat.

Here is a challenge for the weekend for all. Take a walk with an inclinometer. Every fifty yards or so measure the pitch of the surface in the direction of progression and the perpendicular to this.

Here's a second challenge: measure the heel height differential of your shoe.

Here's a third challenge: measure the durometer of the sole of your shoe.

Here's a fourth challenge: measure the durometer of your carpet and underlay.

You see David, while the foot may not have evolved to walk on a hard flat surface. the reality is: we rarely do.

If I find time, I'll do a time lapse video of my daily route to work with angles and inclines of the terrain, but since I'm pretty busy at the moment,
in the words of Cud: "Don't hold your breath, expectorate".

 

Forgot to mention, here's the mathematical proof of why David's theory is wrong:

P = G + E + G x E + i


P = phenotype
E = environment
i = error

 

Forgot to mention G = genotype.

Here's one more challenge: take an old pair of shoes and fill them with plaster of paris, let it set then cut away the shoe to leave the cast. Flat surface- of course not.

 

Hi Simon,


I didn't say the surface was hard, or flat. I could go "Duh", or " no-brainer" but won't (do we say these things in the UK - ?.

I said the surface was approx hard and flat, which it is. We ( in the pod biomech world) are measuring in degree-based increments, after all.
Agree - disagree?

Here's a fifth challenge.
Measure how many reading this actually do the first, second, third and forth challenges - as opposed to accepting you as an expert.
The scientific paradigm is fine and dandy, as long as we agree to run everything by those rules. Wasn't it you, a few years ago, when I suggested I had great results biomechanics-wise, who asked if I had audited figures to prove it?

I see no audited figures to show that you (or CP for that matter) get better results than Ian Linane (seperate practice) or myself.

Simon.
Nowhere have you, or anyone else been able to refute the suggestion that we have not evolved for life on a hard, and flat surface (approx) - J***s H C****t - how often do I have to repeat this!

Please, don't just go " it's not all hard and flat - we know that!".

Respectfully,
Davidh

 

David:

I would need to agree with Simon when he makes the statement that over the past few years of reading your comments on these podiatry lists that you seem to always return to this pet theory of yours that most foot problems occur since our feet were not designed to walk on a hard, flat surfaces. Not only is this a much too simplistic analysis of the multifactorial nature of mechanically-based foot and lower extremity pathologies, but seems to me to be so nonspecific that it is useless information for the clinician (i.e. analogous to saying that all over-use injuries of the foot are caused by gravitational acceleration).

Maybe you could elaborate on whether you think that factors other than hard,flat surfaces are the cause of mechanically-based foot and lower extremity injuries. Also, please let us know whether you prescribe that your patients get new types of employment from hard, flat surfaces to jobs with undulating, uneven and soft surfaces. Likewise, do you tell your patients to move to the country where there are more soft, uneven surfaces or replace their flooring surfaces in their homes with softer more undulating surfaces to alter the injury- causing hard, flat surfaces that they walk on daily? Finally, have you published any of your theories in a peer-reviewed or non-peer-reviewed publication that you could direct us to for further perusal??

 

Kevin,
Most of your second paragraph is nonsense (but amusing ). However, it always interests me that when a pt goes away on holiday (different routine, and often different terrain) they sometimes come back with lessened symptoms.

Simon makes the point that the ground we walk on is not completely hard and flat. I accept that. Great reason, in fact, for our degree-increment posted orthoses not being much more than unquantified wedges attached to a shell, once in use.
I'm not familiar with his work, other than what I've seen written on various forums, and so don't know his findings re the mean pitch of pavements here in the West.
What I do know is that I was able to obtain, using a purpose-built rig (+ 5 degrees accuracy) a mean of around 65 degrees of inversion by applying a torque of 3.9 Nm to a horizontal axis which was pitched to 16 degrees in the transverse plane (approximating the position of the STJ axis in the transverse plane of each subject) in over 100 normal, healthy subjects. I also know that I obtained a mean of around 19 degrees inversion as soon as the feet were placed in the rig (this with a counterbalanced footplate). We even did a small experiment with this rig and diurnal variation, although on reflection this may be a "Durham" thing, since my Supervisor was keen on putting this in, and he was one of the authors of the 1980's paper on circadian variation in metacarpal joint ROM. On one of my subjects I found a variation of over 12 degrees over 12 hours BTW.
Anyway,this overall ROM is indisputably much more than we need to ambulate on even an approx hard and flat surface.

Of course many conditions are multi-factorial. But I believe that underlying most foot problems is the fact that our feet invert when the STJ is in neutral, and have to compensate for each supporting surface. In the case of our hard and flat surfaces I believe the repeated compensation can eventually cause pathological changes in both soft tissue and bone, but much more likely in soft tissue. Unfortunately I believe it is difficult or impossible to predict when these will occur, or what the changes may be, due to the many and changing variables present in us homo saps.

How is any of this relevant to clinical practice?
We (Ian Linane and myself) suggest that if the foot is helped to work a little more around STJ-neutral, then symptoms can be lessened or removed.
This can be done by (as you jokingly suggested) asking the patient to change their home or workplace, or with certain footwear, although my treatment of choice is custom orthoses. These are posted minimally, either FF valgus or FF varus, depending upon what the neutral cast shows. The orthoses work very well, either on their own, or as an adjunct to other treatment, including surgery. I use a normal outside lab for my orthoses, and would like here and now to distance myself from "cure-all" orthoses and other gimmicks.


Now, as to published work, you will find a list (much too small I'm afraid) of my published work if you visit the biog page at the bottom of my post. The research I carried out is written up and lies in Durham University Library for anyone to look at (at the library's discretion of course). This was carried out over a seven-year period in the Bioengineering Dept at Durham, and is, as far as I and my examiners are aware, both original and accurate.
Repectfully,
Davidh

 

Why do you assume that the subtalar joint neutral position is the position of desired rotational position of the subtalar joint for optimal function?

 

Why not?
In a healthy ankle, the talo-crural joint is congruent, and a STJ in neutral will give the foot maximum inversion and eversion necessary for support/ambulation on (variously) undulating, soft, and hard and flat terrains.
Makes perfect sense.

Can you give a reason why you think the STJ should not work around neutral?

Much of the concern about the dogma of STJ neutral seems to come from the fact that most feet move into inversion when placed in STJ-neutral.
But, as I've stated before, this is quite normal, and probably of no consequence in feet which work on a multitude of surfaces, until a variable (like ageing for example) kicks in.
Respectfully,
davidh

 

How flat and hard is "approximately"? How is this different from saying it is hard and flat? How hard is hard? Semantic word play- No brainer (there said it again, got it off my neice along with WMWM).

I'm no expert, but I do have a PhD from the department of Genetics at the University of Leicester, thus I do have a fair understanding of the subject in hand.

I'm not the one putting forward a new theory,and I never claimed to get better results than you or Tom Verlaine. Surely it is down to you to provide the data to support your claims, this is after all the scientific model. Still waiting on those figures though David to support your claims.

Firstly, evolution is just one of a number of possible theories for our existance on this planet, you may need to disprove some of the other theories first.

Secondly, you need to show that the environment that we inhabit during our daily activities (I'll return to this), is sufficiently constant to be considered as a source of repetitive strain. I still say it is not approximately (whatever this is- not a very scientific approach) hard and not especially flat; turn off your computer walk outside your front door and go for a walk, a run, a skip, change direction skip sideways, run backwards, jump, climb a tree, jump from the tree, land and relax, do some yoga, play sport- want to know why we have a bigger STJ rom than we use during walking? Because we don't just walk.

Back to environment: Take two individuals, one is a farmer from Devon, spends his days in the fields and rolling hillsides tending his flock, wearing his wellies; one is an office worker in the city wearing her Jimmy Choo's. Both have Hallux valgus (or any other condition you want to choose David. How does your theory explain this observation. I see this on a daily basis.

Please don't just go "it's approximately hard and flat", how soft and undulating does it need to be to stop all of the foot and lower extremity pathology that you believe is caused by the hardness and flatness? Since this is absolutely central to your theory and is the fundamental flaw in your theory, I think you will find people will keep saying it. "Please don't say that because I can't defend my theory from that flaw" is how it sounds.

Bruckner has demonstrated the variation in the morphology of the STJ, specifically with regard to the number of facets. She suggests that with fewer facets the ROM is increased. In other words with more facets = less ROM. Why do we see variation in the number of facets at the STJ? Which direction is evolution driving the number of facets at the STJ, fewer or more? If you can answer these questions David and show that the STJ is evolving to have more facets this would perhaps be a stronger argument to support your theory. I know you are interested in the fossil record and I'm sure you will find the answer to this question David, Good Luck.

 

Interesting adaptation of Dawkin's theorem Simon, but is G x E + i not just another way of saying 'random variation'?

 

The fossil lower limb/foot record is sparse, and will provide data so limited as to be meaningless, so I won't bother going down that road just yet .
Cheers,
davidh

 

To a certain extent it could be. To be honest I was lazy and missed out the brackets about the (GxE). This is used in quantative genetics to take into account interaction between the genotype and the environment. i in this case is used for measurement error within the the calculation of the phenotypic value. To be honest I didn't know it was called Dawkins theorum- Richard Dawkins? I would have thought this was first described somewhat before his time.

For those interersted in this try:

An Introduction to Quantitative Genetics by Falconer D.S. published by Longman.

 

I guess I was being lazy here....Dawkins proposed an alternative formulation of the phenotype in his book The Extended Phenotype, whereby; phenotype = genotype + environment + random-variation

I'm just not certain if this lends weight or detracts from David's argument on uniform surface ambulation although I take your point on surface variations. Are you aware of any work comparing the incidence in foot abnormalities in barefoot -v- shod populations?

 

Simon,
One other point - I have introduced the "diurnal variation/circadian variation" variable on this forum in the past.
This is a well-recognised and valid phenomenon, as a quick Google seach will show you.
However, I'm not aware of it ever being brought into podiatric biomechanics research.
If I'm wrong, please correct me.
If I'm right then ignoring a variable (which one is aware of) when designing a research protocol is not simply a mistake, but bad science.

Cheers,
davidh

 

Dear Simon

While I don't entirely agree with the vertical heel 2dgs f/foot paradigm,over the years I have read David Hollands theory's,in particular that we have not adapted for hard flat surfaces. He has become frustrated that there was no great response to this. I have always assumed that was because he was stating the blindingly obvious but I am now quite suprised to find the contrary is true and that many find this a totaly rediculous suggestion.
This may be because as David H has said different rules have been applied to the same argument. I take the view that there must be some validity in this point of view of repetitive strain injury due to repeated similar action.
Vasyli have for years used this theory as the basic tenet of orthotic intervention.
"Regain your natural footprint"
Phillip Vasyli wrote "The human foot was originally designed to travel on soft, natural surfaces like earth and sand. Unfortunately, instead of soft earth, we now spend every day walking on hard, flat surfaces like pavements and floors."
Where is the line between hard and soft, flat and rough and their effects in terms of trauma? who knows.
What I do know for sure is that comparable ambulation on a hard surface, whether it is flat or not, produces much higher internal forces than walking on a relatively soft surface.
Humans have the annoying proclivity for not being uniform in structure or activity.
If we were studying the effect of forces on a machine doing the same action and used on surfaces with vaying hardness, I am conficent that it would be a simple job to predict with some accuracy which would suffer fatigue and failure the first.
I would think that if we look at one parameter, like eversion of the foot, it quite likely would have a greater tendency to repeated, continuous and larger medial and plantar soft tissue strains when walking around a shopping centre or working in a bar or on the factory floor, than if it were to spend all day on the beach renting deck chairs.
I don't know what the prevalence of chronic foot trauma is in farmers compared to city dwellers but if it were similar, (which seems unlikely by my experience but then farmers are notoriously tight) then I would imagine that farmer Giles walks a lot further on average than Del Boy plus his unsupportive wellies compared to Del's Brouges may have some bearing on the relative foot problems. Having said that if he walked all day in the sun baked furrows (not in England of course) of his plough, continually maximally pronating his foot then maybe he would suffer greater trauma then Del Boy. But I feel this would be an individual variation that could not be accounted for statistically.
Which is where statistics fall down as they only apply to large groups and not individuals. Are there any studies which statistisally show that people in rural life have different foot pathology to those in city life?
Kevin, I can see your point and agree that this is a simplistic doctorine but is it redundant to point out the obvious or is it prudent. There are things we can do about forces due to gravity, take smaller steps for instance, which is what the elderly often do. It is an interesting concept to use life style as a treatment program and I believe this is used in other fields of medicine to improve a patients health. Would anyone deny that it would be a good idea for someone with a prolapsed disc to give up being a hod carrier (heavy lifting work).
I have a patient who worked at a supermarket as a shelf filler and her feet gave her terrible pain (somewhat less after she had orthoses) but a weeks holiday and she is as right as rain. I suggested getting a till (check out) position, she did and her feet don't now. I think we must have all used this strategy at some time.

Cheers Dave Smith

 

David:

The question is why do you think the neutral position of the STJ is the optimal rotational position of function which seems to be quite central to your argument that "compensation" to hard, flat surfaces cause the majority of pathology in the feet of the human population?? I see many feet that stand 2-3 degrees supinated from the maximally pronated STJ position (and probably 5 degrees pronated from STJ neutral) and function quite normally but are still pronated from STJ neutral during gait. I believe McPoil's gait research confirms this observation. These feet are plantigrade all day, walking and standing on a hard and flat surface, pronated from STJ neutral all day, have no symptoms and have normal gait function. In seeing thousands of these feet over the years, I have come to the conclusion that functioning around STJ neutral is not necessary for normal function and that functioning pronated from STJ neutral is not necessarily the cause of most foot pathology.

You wrote:

Just because you make an orthosis for a patient and the patient gets better, and your belief system says that this must be occurring because your patient's foot is now functioning more around STJ neutral position, this does not mean that your patients are now actually functioning around STJ neutral. How do you know your patients are functioning more around STJ neutral? Are you doing measurements of their gait function with and without orthoses?? Certainly most research now shows that many foot orthoses don't actually change STJ position very much even though the patient's symptoms improve. Do you actually think that just because you take a "neutral cast" and put a minimal valgus or varus post on that orthosis that the majority of patients will now function in STJ neutral??? This is certainly what I was taught by the Root disciples at CCPM but time and again this has been shown to not be the case. I think once you start looking closer at the research that minimal STJ rotational position change is occurring with foot orthoses and that I would expect that your orthoses are not putting as many of your patients into STJ neutral position as you suppose.

And finally, why would you think that just because the patient got better with a minimally posted orthosis that this has anything to do with them walking on a hard, flat surface when in fact it may be more likely due to a multitude of other factors which make much more mechanical sense?? I suppose I just don't understand the leaps of logic that you are making here regarding how therapeutic results from foot orthoses somehow correlate to your theory that their injuries must have been caused by too much walking on hard, flat surfaces during their lives.

Please explain.

 

I really don't think Dawkins was the first to describe this, so it's not really his theorum.

With regard to barefoot vs shod population, the prevalence (it's not incidence) is lower in barefoot populations, demonstrating that the shoe probably increases the prevelance of certain foot deformities. Of interest though is that the deformities still exist in such populations.

When I was nearing completion of my PhD one of the things that perplexed me was the higher prevalence of hallux valgus among females in conjunction with a higher heritability estimate. I felt that the "shared environment of female footwear" (that is that all female footwear was similar enough to be considered as shared environment in quantitative genetic terms) could be elevating the heritability estimate. My genetics based profs (I also spoke with falkener- the author I mentioned earlier) gave a resounding- NO.

 

Dave the reality is that this is not a theory put forward by Vasyli, it is a marketing campaign. There is a big difference.

Lets talk about that soft sand for a while. Has any one walked on a dried lake bed in Africa- not the soft accomodating surface that you might expect. Been up on a glacier in the mountains like our ancestors did or run across the permafrost- yeh, real soft underfoot- not.

Today though I've been wearing a pair of nike pegasus, with full air cushion sole, really hard and uncompliant, you know my feet are really aching- not.

EVALUATION OF CUSHIONING PROPERTIES OF RUNNING FOOTWEAR D.G.E. Robertson 1, J. Hamill2, D. A. Winter3 1University of Ottawa, Ottawa, ON, Canada; 2University of Massachusetts, Amherst, MA, USA; 3University of Waterloo, Waterloo, ON, Canada INTRODUCTION The cushioning properties of athletic footwear have been evaluated in vivo using either ground reaction force or accelerometry data or in vitro with impactors. Unfortunately, none of these methods directly measure the amount of cushioning that a runner experiences. An alternative method for the evaluation of cushioning may involve the use of the deformation power in the foot. Deformation power (Pdef) in the foot may be defined as: Pdef = dEfoot/dt - (Fankle · vankle+ Mankle

 

EVALUATION OF CUSHIONING PROPERTIES OF RUNNING FOOTWEAR D.G.E. Robertson 1, J. Hamill2, D. A. Winter3 1University of Ottawa, Ottawa, ON, Canada; 2University of Massachusetts, Amherst, MA, USA; 3University of Waterloo, Waterloo, ON, Canada INTRODUCTION The cushioning properties of athletic footwear have been evaluated in vivo using either ground reaction force or accelerometry data or in vitro with impactors. Unfortunately, none of these methods directly measure the amount of cushioning that a runner experiences. An alternative method for the evaluation of cushioning may involve the use of the deformation power in the foot. Deformation power (Pdef) in the foot may be defined as: Pdef = dEfoot/dt - (Fankle · vankle+ Mankle

 

For some reason it keeps cutting the bottom off that post?

What I was trying to ask Dave was

Would my foot have a higher Pdef hitting a dry lake bed/ permafrost barefoot, or hitting the tarmac in a pair of nike pegasus?