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Of boots and balance - Page 2

post #31 of 44
Originally Posted by BigE View Post

Would you say a boot with a lower hinge point would be more appropriate for most people than the standard hinge point?

I'm thinking that if the standard hinge point is too high, the heel will have a tendency to lift. That would be very bad if heel pressure should be dominant.

OTOH, if the hinge point is too low, it would just make the boot easier to flex overall. (added leverage)

The hinge point and ankle joint in full alignment would seem the best arrangement, but failing that, too low a hinge point would be better than too high.

That would suggest another decision point in boot fitting, making the process even more difficult considering the narrow range of choices available at the shops.
Form what I know and saw of David's device and his testing, this was one of the big issues. Not only location, but also having a true hinge point as opposed to plastic deforming to accommodate flex. I wish I knew more.

From a personal perspective I think is one of the biggest issues for me in how a boot flex feels and how it integrates with my own movements. Fit and how the boot flexs with my geometry is what I go by first. Later, RicB.
post #32 of 44
Thread Starter 
Originally Posted by bennyr View Post
I'm pretty sure that he didn't make geometric changes, but it has been years since I've seen the article (I'm embarassed toadmit that I wouldn't know where to find it). My recollection was that he was using high level skiers who would be pretty functional stance and balance-wise.
Have fun.
bennyr, I've got an e-mail into Ron. I'll let you know what I hear...
post #33 of 44
The boot with a hinge point sounds a lot like a flexon (krypton). One theoretical problem with a boot like that is that there is one optimal dorsflexion angle. If you need more dorsiflexion, and make the boot tongue more upright, the tongue resists with less force. Of course there are all the regular boot and calf size issues with any boot as well. A boot like the flexon would seem to be a good starting point for a series of semi-customized boots. Select a lower boot based on foot and instep size, select a tongue based on required dorsiflexion, and select a cuff based on calf size. Then adjust the sole to get the required cant and lean angles.
post #34 of 44
Would'nt that be what "custom" bootmakers actually do? I mean they are not going to mill a mold just for you, are they? I think they'd just take their best fitting components and assemble them. Or inject an existing mold for you.

You're still going to be at the mercy of the hinge point and orientation of the direction of flex to the lower.

When you flex krypton, does the cuff actually track straight or does it track/rotate inwards? I'd suspect of all the boots, these would track the straightest. What can you do to get more instep room? Do you actually heat and punch the tongue?
post #35 of 44
Thread Starter 
Most high-end (racing/plug) boots are built like this by a good fitter/balancer. They'll use a cuff, lower shell, and customization (hinge locations, flex changes, etc.) based on physiology and preferences.
post #36 of 44
Oh, if only I could afford all that!

I don't think there is anyone around here that does such custom work.

They would *change* the hinge location for the cuff canting, but they'd work with a "stock" product -- which would mean stretching and grinding the cuff to fit, and repositioning buckles, as opposed to substituting larger/smaller cuffs.

Anyone know who's got the best race boot fitter in Toronto?
post #37 of 44
Thread Starter 
Originally Posted by BigE View Post
Oh, if only I could afford all that!

I don't think there is anyone around here that does such custom work.

They would *change* the hinge location for the cuff canting, but they'd work with a "stock" product -- which would mean stretching and grinding the cuff to fit, and repositioning buckles, as opposed to substituting larger/smaller cuffs.
There are a couple of ways of doing this, including picking the boots based on what you need. Some of the high-end boots have multiple locations for the hinges, some can be drilled, some can be cut, etc. to do this.

Can't help you with Toronto, but why not jump over the border to GMOL or one of the Stowe guys?
post #38 of 44
That's a 12 hr drive one way, which will add even MORE to the cost of the work. I'm lucky to afford the time on hill that I have!
post #39 of 44
Ricb, I agree, we need more studies in this area to determine what is optimum.

I think I remember LeMaster's test and it was more of an observation of where pressure was greatest during ski turns which is a little different than what we are talking about here. I would guess that everyone tends to load the tail of the ski more after the falline whether their boots place them in the optimum position or not.

It makes sense to me to find the most optimum static position in the boot/binding/ski system from which to move to be able to maintain optimum dynamic balance.

We need a government grant for all of us to spend countless hours skiing and testing theories on the subject. Wouldn't that be nice...
post #40 of 44
Thread Starter 
This from Ron LeMaster:
Originally Posted by Ron LeMaster
There's been a fair amount of research done on this over the years, mostly by groups at universities in Salzburg and Innsbruch. The common approach is to put arrays of sensors of one sort or another either inside the boots, under the footbeds, or somehwere between the soles of the boots and the tops of the skis. Data from the sensors is recorded in synchornization with video of the skiers going through some sort of prescribed turns.

The results I've seen have pretty much agreed with what you would think from looking at the bend in the skis and where snow is coming out from under the skis in various points in the turns. This goes for both fore-aft and lateral balance. One study showed results that indicated pressure was farther back on the ski more often than I would have suspected in some cases.

Good sources of published work are Erich Mueller and Christian Raschner. You can also look for the procedings of the International Congress on Skiing and Science (or ICSS).
post #41 of 44
Thread Starter 
By the way, David MacPhail did do this research, and over time as nolo edits out the 1000+ pages of information on it, we'll have more available in the Premium Articles section of EpicSki.
post #42 of 44
Originally Posted by ssh View Post
So, I'm wondering about this... How do instructors deal with these kinds of issues? It seems to me that teaching someone who isn't at least reasonably balanced in their boots could effectively be teaching compensatory movements.

This is our dilemma today. On one hand instructors are more savy than ever to the importance of stance alignment but in many/most cases are prohibited by their ski school or personal fear to make any adjustments to their clients equipment on the hill. Although this is exactly what needs to be done to demonstrate to the client that their equipment is holding them back and that some simple adjustments can reap huge rewards in their skiing progression.

On this fore/aft plane the instructor could easily pull a shim or two from their parka and slip them either inside the boot or between the heel or toe of the binding and affect various noticable results for the skier.

instead of tryng to put a bandaid on the cause of the problem by doing exercises that he/she knows are compensatory he/she could be doing a real service to enhance safety and performance.

But instead I will now bang my head against a wall.
post #43 of 44
Thread Starter 
I've seen you use duct tape... Are there other shim styles that are less likely to inhibit binding function? Or are the friction characteristics of duct tape (or other materials) such that they are negligible?

I know that there are a couple of pilot projects at major (and influential!) resorts that are ongoing, so don't lose faith quite yet!
post #44 of 44
My good buddy Arcmeister turned me on to using small pieces of cut up plastic cant strips with a small piece of duct tape attached as a handle to avoid pinched fingers while staging the shim for engagement in the binding. This harder material is preferable to tape and takes less time but is easier to lose in a fall or release. I still use bontex (pressed cardboard) for changing the fore/aft angles. If I find some hard plastic the is of equal thickness in one and three mm increments I will certainly use it instead of bontex shims or duct tape.
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