Planal Dominance, applications

[Admin]

robertisaacs said:

Don't worry Rob, they do calm down eventually!

Says You!!! Teething. Why Do they teeth .


;D


Much cut.............

Leaving aside planal dominance, axis, degrees of certainty etc, Try this.

Some foot types the navicular drops loads.
Some foot types the navicular drops about as much as it drifts
Some foot types the navicular drifts loads and drops little

Different insoles work better / worse depending on these foot types.

Agree? Disagree?

Regards
Robert

Agree. However...
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Only joking!

I agree completely. Your examples are wholly logical and easily demonstrable.

Cheers,

[robertisaacs]

Super

This is a good demonstration of the dichotomy between the researcher and the clinical approach. You see for me the three "types" of foot descibed above are explained and justified by planal dominance. You might think the cause is something different. However the end result is the same, we recognise the same phenomina and come up with solutions based on what we observe.

Its a bit like the difference between a mechanic and a racing driver. A mechanic might know that when he puts his foot on the gas it increases the flow of fuel to the cylinders which causes a higher explosion force, faster piston movement and more torque to the drive shaft (or something!). A racing driver knows when he puts his foot down it goes vroooooom. Both can drive well, possibly based on different understandings of the same process.

I think planal dominance (or what-the-navicular-does-on-weight-bearing if you prefer ) is a usefull test to do as part of an assessment and often explains why an insole has not worked / been uncomfortable.

Regards
Robert

[ianl]

Hi Rob

Then we have the foot that does not exhibit great levels of navicular drop until early to mid heel lift and then does a sudden drop with equally sudden internal knee rotation leading on to a toe off with a medially rotated knee and inappropriately lowered mid foot but a calcaneum that seems to remain at vertical. Probably written badly, in a rush, sorry.

There can well be a broad grouping of feet (for discussion or learning processes) but the surprise lies not in that but noticing how any of those feet have their own eccentricities, as hinted at in the badly written paragraph above. Interestingly many of those feet, even with their eccentricities, can respond well to very simple intervention that have very little in terms of difference in their prescription.

In general, when assessing a patient, I prefer not to place their feet into a certain type category, rather, simply accept the feet as normal to them and work from there as to how to achieve something. Indeed with some feet that have had obvious navicular bulge I have even put valgus postings which seems contrary to what we may see and could have easily categorised. Whatever the foot type keep it simple and look to balance it.

Sorry to be rushing
Cheers
Ian

[robertisaacs]

Hey Ian

Then we have the foot that does not exhibit great levels of navicular drop until early to mid heel lift and then does a sudden drop with equally sudden internal knee rotation leading on to a toe off with a medially rotated knee and inappropriately lowered mid foot but a calcaneum that seems to remain at vertical. Probably written badly, in a rush, sorry.

Sounds to me like a windlass failiure.

There can well be a broad grouping of feet (for discussion or learning processes) but the surprise lies not in that but noticing how any of those feet have their own eccentricities, as hinted at in the badly written paragraph above. Interestingly many of those feet, even with their eccentricities, can respond well to very simple intervention that have very little in terms of difference in their prescription.

I only partly agree here. I agree that some feet will respond to a "simple intervention". Others i find, will not. The trick is identifying which group is which BEFORE you try what you are trying.

Most people who go to the doctor will respond well to co-codamol. But you can't give it to all of them on the basis that it so often helps!

In general, when assessing a patient, I prefer not to place their feet into a certain type category, rather, simply accept the feet as normal to them and work from there as to how to achieve something. Indeed with some feet that have had obvious navicular bulge I have even put valgus postings which seems contrary to what we may see and could have easily categorised. Whatever the foot type keep it simple and look to balance it.

And here i must respectfully disagree. Whilst i accept the impossibility of the concept of the "normal" foot i do feel that there are certain anatomical / functional "patterns" which consistantly and demonstrably exert characteristic stresses on certain tissues. I would agree that there is a danger to "catagorising" types of feet, however there are identifiable and diagnostically useful aspects of structure and function which occur in many patients.

Perhaps "catagory" is the wrong word. A group of people suffering with broken legs are not a catagory, yet they have a similar problem and will benifit from similar treatment.

You said:

Whatever the foot type keep it simple and look to balance it.

The concept of "balancing" might be subject to questioning, what exactly does this mean? Balancing implies maintainance of equilibrium, what equibrium are you seeking to maintain, in what position? Not a "NORMAL" one surely ;D .

Keeping it simple is a noble goal, but is there a risk that this involves ignoring useful information?

I think that there are two extremes to avoid here.

"catagorising" feet into "types" and treating on that basis is not a great plan. You can miss some of the nuances when seeking a pattern, you can incorrectly emphazise information based on trying to make it fit "symptom sets". This, i think is what many podiatrists and other medics do and what a certain retail chain which rhymes with Mole do so well.
"heel pain? caused by pronation isn't it? Does the foot pronate? So it does! Arch supports all around!"

The other extreme is to be TOO freeform. There are patterns which have been empirically AND evidencially (is that a word? Is now.) shown to be diagnostically significant and repeatably increase tissue stress in certain structures. Ignoring these for fear of falling into trap number 1 is to miss out on some useful patterns of information which can make treatments more effective.

Regards
Robert