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alignment, shims and binding eccentricity

post #1 of 12
Thread Starter 
Hi everyone, first post so here goes:

Some skiers have a knock-kneed skiing stance due to the natural movement of their knees inwards towards each other when their legs are flexed. Am I correct in thinking that though they could pull their knees apart a bit with conscious effort, if medial shims are put in their boots then if on a flat hard surface their natural stance won't be so knock kneed? What would then happen on an uneven soft surface or during a turn (with ski on edge)? Would they revert to a knock-kneed leg position? After all, the shims only worked because they caused the feet to be layed on a flat surface in a different attitude and it was only then that this translated upwards to a different leg position.


Does then the answer for these skiers lie in either training the legs (“lazy inside leg”, “thigh steering exercises”) or maybe repositioning the bindings. If the bindings are positioned so the toe-piece is a little to the outside edge and the heel-piece a little to the inside edge, so each foot is in a little valgus, the slight external rotation of the femur allows the knees to flex without moving inwards towards each other.


Am I talking rubbish?

Hope it's ok that I've posted this in the Ski Gear Discussion forum too as I'm also interested in the thoughts of the general membership.

Thanks in advance!
post #2 of 12
now then slik, i prepared a long post for you responding to this over on SH's but i deleted it by hitting the wrong button, i will have to think and re write when i get some time
post #3 of 12
YOu clearly have given this some thought and seem to know the terminology so I'll assume you have some background. Don't have time for a long post but I will add some thoughts.

Yes I believe it is possible to train the body to correct alignment. And there is evidence it is correct however it doesn't mean that most people (due to lack of training time and other reasons) will be able to achieve it.

Last week I was working with a Canadian National Team athlete on the Tekscan. I remarked at how neutrally he was aligned and how I found it to be typical of athletes at his level. He commented that they constantly train alignment and that he could no longer differentiate his natural (old) alignment from the way he now stands. In other words he isn't certain any longer what his natural alignment is.

Also when I started my MSc I read a very interesting study conducted in India. Don't know your age but when I was a kid the thought was that sneakers lack of support was causing all children to be flat footed. Intuitively with sound reasoning not correct, but that was the thought of the day.

A study from India studied just that. One cohort of kids living in same village, attending same school, playing same sports. In other words alike in every way except some wore shoes and others lived barefoot.

Barefoot group had higher arch index. Higher arch. Probably due to muscle activation necessary when an external arch doesn't provide support for the foot

Lou
post #4 of 12
This is a very sound question, and since I am “the shim guy". I suppose I ought to kick things off on this subject.

First thing that comes to my mind is this, if the knees is inward due simply to curvature of the femur and tibia and that is just the natural configuration of the leg I would not put shims into the boots to fix that. I feel that the knee position is just that, and merely a measurement that tells you where your knee is in relation to the foot. It is usually not a problem as much as a symptom. Now if the knee ROTATES inward because of the biomechanics of the foot inside the boot that is a whole different problem. It is crucial to distinguish weather the knee is there because of pronation or just normal growth patterns. To understand the difference, if there is rotation it is a pronation issue. To understand pronation we must look at the foot and ankle. In this view we separate all the variables. Lets not confuse symptoms and actual problems.

The interesting part of this question was looking at soft snow as a way to make the effect of the shim inside the boot less effective? I like the way you think. Here is my thought on this. I would say that if you were to say you are balancing on something obviously the snow provides a surface to stand on but as soon as you are moving that surface becomes a dynamic surface like water lets say. So then what becomes the constant? I would suggest it is the boot that is connected to the ski. So for now, lets call that the equipment system. But in this view we are balancing on the system, not on the snow as the constant so I would say that the shim still has an effect on the foot but because the snow is so much more dynamic the effect is slightly less important than on hard snow. Many things change when the snow is soft but I don’t feel it makes the subtle foot movements inside the boot less important and this is what the shims are all about.

Your question concerning inside knee activity? Pronation has everything to do with inside leg activity and weather you will be able to access this leg effectively. A pronated foot inside the boot will not allow equal access to the inside and outside edges.

Let’s understand that the knee joint is simply a single plane hinge joint. It only bends in one plane of movement. The hip and the “ankle” are triplanor joints. They move in three planes. So without the hip and ankle the knee would only be able to flex in a forward manner. So where is the problem in the knee or the foot? I would say usually it is the ankle/foot end of the chain. So when you say that the knee is “Knocked” I say ok but why? The knee usually is the symptom not the problem.

If pronation is what causes the symptom of the knee. What would you like to do about it? Move just the knee and ignore pronation, or reposition the foot to stop pronation which happens to stop the rotation?

I would propose that all the following be considered for different reasons. However if you want my priority list, this is how I see things.

•Foot beds (old or new).
•Measure pronation and lateral boot board angle.
•Appropriate Shims under foot beds (for optimal foot position using boot and foot measurements).
•Adjust the cuff (to match the shape of the leg).
•Grind boot shell or Cant bindings (when needed).

Other people use a very different priority list however this is only my view. I put a lot more weight on understanding the foot /ankle inside the boot, and no little on knee position.

In your question of someone that has severe knee knock and no pronation I have only seen one case and that guy was a podorthist himself.

If there is no pronation I would deal with the knee issue with a boot grind to allow the cuff to adapt to the angle of the leg as it is. Not to try to move the knee into an unnatural position to look like a parallel legged skier.

Sorry about the length here but that is what happens when you ask intelligent questions.
post #5 of 12
You are correct in stating that the goal is to have the knees tracking straight ahead over the ski tips. How this is achieved and what is most desireable is what is in question. Talking to a pediatrist you will probably hear the argument that this can all be corrected with an orthodic which will rotate the knee to the desired position. Talking to an excercise or physical therapist you may here this can be corrected through excercise and training the appropriate muscles. Talking to a world cup boot technician you would probably hear that external canting the boot is the solution. Talking to a Nordica or Fischer rep you may hear an abducted boot is the answer.

I tend to favor the last two as I know that an orthotic alone in a ski boot will not correct knee tracking, and most recreational skiers will not dedicate the time or effort neccessary to manipulate the muscles to correct the problem.
post #6 of 12
Quote:
Originally Posted by slikedges View Post
Some skiers have a knock-kneed skiing stance due to the natural movement of their knees inwards towards each other when their legs are flexed. Am I correct in thinking that though they could pull their knees apart a bit with conscious effort, if medial shims are put in their boots then if on a flat hard surface their natural stance won't be so knock kneed? What would then happen on an uneven soft surface or during a turn (with ski on edge)? Would they revert to a knock-kneed leg position? After all, the shims only worked because they caused the feet to be layed on a flat surface in a different attitude and it was only then that this translated upwards to a different leg position.
I think the important to think about the platform and how we stack in relation to that platform. The issues you discuss above become progressively more of an issue as the platform (snow) becomes firmer. I have done experimentation with extreme over and under canting in powder and firm snow and in powder the misalignment is much more manageable than on firm snow where as little as 1/2 degree is fairly noticable.
post #7 of 12
slik, are you going to be at the B'Ham ski show, Andi is coming up with me and will be doing free balance healthchecks, worth bringing your boots

we will be on the Fall line mgazine stand
post #8 of 12
Thread Starter 
Firstly, apologies for the late reply, but I've been very busy at work of late. Coming up for a bit of air this weekend but then back into the thick of it next week!


Secondly, thank you all for the brilliant and insightful replies from all you guys!
post #9 of 12
Thread Starter 
Quote:
Originally Posted by CEM View Post
now then slik, i prepared a long post for you responding to this over on SH's but i deleted it by hitting the wrong button, i will have to think and re write when i get some time
The number of times I've done this...Nowadays I try (and don't always succeed) to select all and copy all long posts before hitting post reply, just in case. Particularly galling as I seem to be dropping my ADSL connection a few times a session at the mo (!?).

Probably won't be going to Brum I'm afraid (when is it again?), so will miss McCannix, but will come see you in your lair at some point, if ok.
post #10 of 12
Thread Starter 
Quote:
Originally Posted by Lou Rosenfeld View Post
Yes I believe it is possible to train the body to correct alignment. ... He commented that they constantly train alignment and that he could no longer differentiate his natural (old) alignment from the way he now stands. In other words he isn't certain any longer what his natural alignment is.
Interesting that they should pursue this philosophy when it may be that it is quicker and easier to correct alignment by some external measure. Perhaps they don't think it's as effective to use external aids? Do you know how exactly they train alignment to such an extent?

Quote:
Originally Posted by Lou Rosenfeld View Post
... when I was a kid the thought was that sneakers lack of support was causing all children to be flat footed. ...

Barefoot group had higher arch index. Higher arch. Probably due to muscle activation necessary when an external arch doesn't provide support for the foot
This is interesting. As you say it's intuitively not correct that it should be due to lack of support in the shoe, after all many peoples still have no shoes and all are not blighted by flat feet! I guess though that it must be possible to support a foot in a shoe at the least without compounding the problem!?
post #11 of 12
Thread Starter 
Quote:
Originally Posted by bud heishman View Post
... Talking to a pediatrist ... Talking to an excercise or physical therapist ... Talking to a world cup boot technician ... Talking to a Nordica or Fischer rep ...

... and most recreational skiers will not dedicate the time or effort neccessary to manipulate the muscles to correct the problem.
I suspected this might partly be the case! Roll on the off-set toe non-Race Dept Nordica (next season?).
Quote:
Originally Posted by bud heishman View Post
... The issues you discuss above become progressively more of an issue as the platform (snow) becomes firmer. ...
I guessed this'd be what happens. My thought was that shims worked to best effect on firm snow and that though fine edge angles matter less in soft snow, symmetry would still suffer.
post #12 of 12
Thread Starter 
Mosh, very comprehensive and detailed answer and I thank you for that. I think it certainly makes sense that if the problem is largely due to foot/ankle pronation, this should be addressed first. I can see how a tendency to overpronate could result in a knock-knee. And if it isn't I can certainly perceive of situations where an external measure may well be hazardous. However in a proportion of patients, the problem may surely be due to an excessive valgus position of the foot, which may be sufficient, when forced into parallel skis and boots, to produce internal rotation at the hip and a knock-knee on flexion. Would you feel it ill-advised to reset bindings, boots, to accommodate for such a case?
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EpicSki › The Barking Bear Forums › On the Snow (Skiing Forums) › Ask the Boot Guys › alignment, shims and binding eccentricity