Speculations on alignment issues....

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Speculations on alignment issues....

Postby tommy » Wed Jan 21, 2004 7:12 am

I've spent some time thinking about alignment in general, and canting in particular. I'd appreciate any insight from the people on the forum on these issues.

To better describe my questions, I'll take myself as an example: I'm knock kneed, and it appears to be more on my right side. For a while ago, I got a suggestion to cant my right boot, which I have found to be very beneficial to my skiing. However, after having decided to try canting, I got a bit confused about how to apply it: the tools available to me was a plastic wedge, with appx. 1 degree tilt. The idea was to place this wedge under the heel of my boot. But the question became: on which side of the heel (inside vs outside) to place the thick side of of wedge ? From a theoretical point of view, I could find arguments for both approaches:

a) place the thick side of the wedge on the outside of the heel, which would allow my knee to stay in its normal position, but still (hopefully) flattening the skis contact with the snow by modifying the angle where the boot attaches to the binding, i.e. tilting the ski.

b) place the thick side of the wedge on the inside of the heel, i.e. attempting to mitigate my knockneedness, by moving my knee out.

I went for alternative b, and it turned out to be very beneficial, but I'm just wondering whether I could have had similar, positive effect by attempting alternative a.

An other way to describe the difference in the two alternatives might be that in a) you make a modification to the "geometry" of your gear, while keeping the body stacked as it is, while in b) you modify the stacking of your body.

A second question is about the difference (if any) about what can be done in terms of canting, when using custom made (like Harb ski systems) footbeds, and using canting wedges/shims ? Assuming a "perfect" footbed, would there still be any need to use a wedge/shim ? I guess that footbeds, in addition to allowing for adjustment of alignment, also have aspects in supporting the foot, and comfort, but it seems to me that a "perfect" footbed would make any additional canting unnecessary?


Cheers,
Tommy
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Postby jclayton » Wed Jan 21, 2004 9:56 am

Hi Tommy,
I think that footbeds would have to keep the foot supported but in a neutral position inside the boot , it would be detrimental ,surely,
to have any sort of canting of the foot bed . Harald makes a strong point for use of ankle articulation inside the boot . I don't think you could articulate properly if the foot bed wasn't neutral . Also footbeds are tending towards a softer support and I now get much more feel than I had with my old stiff one even with stiffer boots and an injected inner .

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Postby BigE » Wed Jan 21, 2004 2:58 pm

The thick part of the wedge goes on the outside if knock kneed. It goes inside if bowed. The effect is to lengthen the appropriate side so that the ski is flat to the snow. It is not to adjust your bodies natural alignment.

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Postby jbotti » Thu Jan 22, 2004 9:47 am

I actually think that the wide part of the shim goes on the inside part of the boot. I am extremely knock kneed and I have been to see Harald for alignment. On my right leg it required a three degree adjustment so that my knee would flex over my ankle rather than inward towards the other leg. Harald accomplished this by shaving my boot. The outside part of the heel was shaved changing my alignment. I feel reasonably confident that if you are using a shim to produce the same result you want to raise the inside part of the heel or lower the outside part of the heel (which is not possible with a shim). I think doing the opposite will only make you more knocked kneed. By raising the outside part of your heel you are making your knee point more towards the other leg, and it will flex even further towrads that leg.
Balance: Essential in skiing and in life!
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Postby tommy » Thu Jan 22, 2004 10:01 am

jdb,

from my own experience with the wedge, where I placed the thicker side on the inside of the heel, I'm leaning more towards your solution. I.e the idea is to modify (align) the knees position from its knockneed "default".

I would suspect that, as you say, doing it the other way would actually increase the level of knockneedness. But again, from a theoretical point of view, both approaches might seem to be possible.

Time permitting, I'd like to try out the other approach just to see what happens.

Cheers,
Tommy
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Agree with Jbotti

Postby Guest » Mon Jan 26, 2004 8:53 pm

I'm pretty sure that jbotti is correct. The purpose of the cant is to center the head of the tibia (just under the knee over the joint between the first and second toe). The problem with knock-kneed or bow-legged is that it gets the mass of you body inside or outside of the ski, which makes edging the ski very easy on one side and very hard on the other. Canting get your mass more over the center of the weight-bearing base (the first two toes) so that edging to either direction is equally easy. Putting the cant on the opposite side would effectively make you MORE knock-kneed. Harald's book also mention that wide vs. narrower skis can also help a severely knock-kneed or bowlegged skier.



jbotti wrote:I actually think that the wide part of the shim goes on the inside part of the boot. I am extremely knock kneed and I have been to see Harald for alignment. On my right leg it required a three degree adjustment so that my knee would flex over my ankle rather than inward towards the other leg. Harald accomplished this by shaving my boot. The outside part of the heel was shaved changing my alignment. I feel reasonably confident that if you are using a shim to produce the same result you want to raise the inside part of the heel or lower the outside part of the heel (which is not possible with a shim). I think doing the opposite will only make you more knocked kneed. By raising the outside part of your heel you are making your knee point more towards the other leg, and it will flex even further towrads that leg.
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Postby BigE/Erik » Fri Jan 30, 2004 2:58 pm

I've recently returned from a visit to a sports medicine clinic. I asked the doctor if canting would help my knee pain. I am quite bowlegged, so I asked specifically if planing down the inside edge of the bottom of the boot to help bring the knee over the toes would help.

The doctor said that it could help with the pain, and that it is certainly the right adjustment to make. So the for bowlegs, the wedge goes on the outside. For knock knees, it goes on the inside.

In my own case, he's going to check the x-rays before suggesting that stance alignment alone is sufficient. I may require what he called a radical procedure: a "high tibial osteotomy" (HTO) to correct the bowleggedness and avoid the osteoarthritis I face in retirement. His words: "I'd wait until the xrays come back. But then, it's your money....".

In an HTO they either take a wedge out of your shin bone (the tibia) or graft one in, so that the tibia is straightened out under the thigh bone. That way, the end of the thigh-bone can distribute weight equally on both sides of the tibia. In bowlegged people the weight bearing side is the inside of the knee, so the cartilege on that side wears out first.

Other options are knee braces to push the knee inwards, but "there is only so much you can do with orthotics and braces" he says. Yiikes!

I'll find out what to do about it on Wednesday.

Sheesh! All I wanted to do was to find a way to pay for orthotics on my drug plan!
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