How Do High DIN Bindings Relate to Knee Injuries?

[hucksquaw]

fo sho. markers do have a tendency of pre-releasing.

[BakerBoy]

fo sho. markers do have a tendency of pre-releasing.

Marker's release to the best of their designed ability, and do so at exactly the same load every time, the instant that point is met. Thus, the inherent design flaw for people who don't ski on groomers. But Brad Holmes loves them.

[Mechmaster]

Most of the pre-release issues with Markers are related to the backward-fall release mechanism. See

http://www.markerusa.com/site.jsp?sk...indings_safety

and look at the "Biometric programmed release". The amount of load required to release backwards is 20-50% of the lateral loading. Thus, an inadvertant bump or loss of balance can easily trigger the mechanism and release the skier. Also, once release conditions are met, the cam in the toe makes it unlikely for the boot not to release.

Marker team bindings replace the Biometric mechanism with a solid plate. This improves the retension greatly.

As said before, Markers are biased towards release over retention (less lateral elasticity).

Neither the Look/Rossi toe or the Salomon (Spheric) toe release upward at a different loading than laterally, although the Spheric system is designed to "push" or start the toe releasing in certain conditions. Both designs have improved lateral elasticity over the Marker toe. Salomon Spheric has "dual inclined pivots" which imply that the binding release path is "up and out" rather than "out" in all cases.

[Plakespear]

do you get all your info online? maybe thats why your so fuckin stupid when it comes to skiing.

well maybe you should check atomics site again b/c it does say their bindings release backwards.. dumbass

and word for word on the atomic site says...

This explains a lot.

[joshbu]

Well, I took a backwards twister in AK last year on a set of 916s whose DIN was too high for me (on that particular day) and whose toe wings were not well calibrated. I came out, but not after giving my knee a good twist. Result: torn meniscus.

At any rate, in the Solly case, the toe wings release is tied to the DIN, as CD says. I would assume that is the case with the other front release mechanisms on other bindings. That's why the toe piece HAS a DIN setting.

[altagirl]

Release mechanisms aside, I've read/heard that you can tear an ACL even if your bindings are set on zero and you're wearing a fancy custom knee brace. It takes very little movement and force - it's more a matter of falling into the wrong position and then trying to stand back up, which is not really putting much force on the binding, just on your knee. If they made a brace tight enough to totally prevent it you couldn't move, and if they made bindings release easily enough you'd never stay in them at all. Bottom line is that you can't depend on any binding to protect your knees from all injuries. The way I understand it, keeping DIN settings in the normal human being range is more to protect your bones than your ligaments.

Feel free to tell me I'm an idiot though...

[summit]

the knee joint is a horribly fragile joint and the ligaments in it are horribly fragile as well.

[Duker]

fo sho. markers do have a tendency of pre-releasing.

Yeah Ive never seen an atomic binding pre-release. Hopefully that new super gizzmo computer binding solved this. But even if it did is it worth paying $1000 so your binding can tell you that you have snow under your boot as opposed to paying >$200 for a proven solly or look binding?

[Donald Trump]

hucksquaw,

YOU'RE FIRED.

[Stikki]

What the heck is a "backwards twisting fall" anyway?? Do you suddenly become a f'ing retard and fall over backwards while turning? Seriously.

Picture this, you’re ripping down a 40-degree chute and graze a submerged ice chunk. Thrown slightly off balance and into the back seat you fight to get your hands forward and up over your skis again. Suddenly you realize that you are hurtling ever faster down the chute and take notice of the trees coming at you. Instinct takes over and you initiate a turn to avoid the trees but being that you are tail gunning one of your skis twists uncontrollably away from you. Pop! There goes the weasel. Season over. And remember this all happens in less than a second.

[Spats]

The Salomon "Spheric" toe isn't designed to do anything in backward twisting falls: it's designed to make the boot release better in forward twisting falls. Think about it: the plate is under the boot...if you're leaning backwards, the boot is pulling up on the toe and no contact is being made there.

Pushing down on the Spheric plate makes the binding release more easily to the side. Additionally, when the toepiece releases, it twists slightly up in addition to rotating. This gives the boot some vertical clearance so it can pop out even if it's being twisted, unlike a purely rotational release where twisting along the axis of the ski will bind the boot and keep it from coming out.

There are several problems with this mechanism:

1) Setting a hard edge twists the boot in the binding, putting pressure on the Spheric plate and causing the toe to release at lower DIN than otherwise. In my opinion, when you set a hard edge is exactly when you don't want a binding to release.

2) Landing hard off a jump, especially to flat, puts a lot of downward pressure on the Spheric plate. Again, this causes the toe to release more easily precisely when you don't want it to.

3) In order to sense pressure, the Spheric plate has measurable travel. When setting a hard edge, the Spheric plate is pushed through some part of its travel -- and even if you don't release there will then be slop in the toepiece. This is particularly noticeable with very wide skis, where the twisting force on the binding is high. The ski will not set an edge well, and will frequently chatter due to the slop.
You can test this yourself: even squeezing the Spheric plate with your fingers will push it in a mm or two. The newer Spheric Oversize (silver/black/white AFD) is much worse than the old generation (yellow/black AFD).

4) This isn't a Spheric problem, but issue 3) is exacerbated by the flexy plastic construction, and by the fact that the toepiece is only actually attached to the rest of the ski by a small pole in the center. Grab the toe wing with your hand and squeeze it toward the ski: you'll notice that you can move it quite a bit.

The summary of all these problems is that recent Salomon bindings have very low torsional rigidity, causing chatter and loss of edge control with fat skis on hard snow -- and they will tend to release precisely when you don't want them to.

I have seen all my prerelease issues go away after switching to Look/Rossi: I've skied the last two years on Pivot bindings set to DIN 6.5 and never released prematurely, versus having prerelease problems on S912 bindings at 8. I'll be experimenting with Tyrolia this year -- the other alpine binding manufacturer whose design isn't intrinsically flawed.

[joshbu]

<paraphrase>I never fall. I am in control at all times.</paraphrase>

May I suggest www.epicski.com? They don't ever fall over there either.

Spats: Are you talking about Solly consumer bindings? I'm pretty sure my 916s don't have the spheric toe, the the wings are metal. They don't really flex at all.

[Dexter Rutecki]

Release mechanisms aside, I've read/heard that you can tear an ACL even if your bindings are set on zero and you're wearing a fancy custom knee brace. It takes very little movement and force - it's more a matter of falling into the wrong position and then trying to stand back up, which is not really putting much force on the binding, just on your knee. If they made a brace tight enough to totally prevent it you couldn't move, and if they made bindings release easily enough you'd never stay in them at all. Bottom line is that you can't depend on any binding to protect your knees from all injuries. The way I understand it, keeping DIN settings in the normal human being range is more to protect your bones than your ligaments.

Feel free to tell me I'm an idiot though...

That's basically true, although the DIN on zero thing might be a very slight exaggeration. I've blown through two ACL's now, and no binding could've saved either one of them (bindings never released in either crash, but they should not have released, and it wouldn't have helped if they had).
And of course no brace can protect your ACL, as the few mm of movement the ACL restricts are too fine a movement for any brace that isn't drilled into your bone to guard against. I am curious about some of the newer studies that seem to show lower reinjury rates among brace wearers, though--my guess is either the studies are somehow exaggerating the effect through a form of self-selection, or people wearing the braces are behaving differently (smarter?) than those without.

But we'll continue to feel free to call you an idiot

Hucksquaw making a big push for JOTY status.

[Spicoli]

THIS JUST IN.......

People who don't even ski get ACL injuries







Hucksquaw's trolling hard and gettin' lots of bites too

[dipstik]

If it helps any, my Atomic race 412's from 00-01 had a little switch on the top of the toe piece that read something like "backward release" and you could turn it on or off using a screwdriver...


So one time I set the DIN all the way down, clicked a boot in, and tried to get it to release straight up and back, but it didnt work.

[Idris]

THIS JUST IN.......

People who don't even ski get ACL injuries







Hucksquaw's trolling hard and gettin' lots of bites too

too true, as a race kid 4 of my buddies lost acl's playing soccer and none from skiing...playing with a soccer ball in a parking lot is way more likley to wreck your knees than skiing!

[altagirl]

And of course no brace can protect your ACL, as the few mm of movement the ACL restricts are too fine a movement for any brace that isn't drilled into your bone to guard against. I am curious about some of the newer studies that seem to show lower reinjury rates among brace wearers, though--my guess is either the studies are somehow exaggerating the effect through a form of self-selection, or people wearing the braces are behaving differently (smarter?) than those without.

My guess is that it is because some ACL injuries are the result of actual crashes where a brace could protect you vs. the typical backseat rearward falling deal that is so difficult to protect against. But that's pure speculation. It could also be, like you said, that brace wearers are skiing more conservatively. Though my first surgeon didn't want me to ever wear a brace because he felt it would have the opposite effect and I'd think I was invincible and be more likely to hurt myself or push too hard to soon. Personally I don't find that to be true with a brace or a helmet (where you hear the same type of arguments) - if it's comfortable I don't notice it and I just ski normally - the only difference being that if I'm used to using it and suddenly am not wearing it - THEN I'm more conservative. Hard to say for the general population though.

[Darkside]

Picture this, you’re ripping down a 40-degree chute and graze a submerged ice chunk. Thrown slightly off balance and into the back seat you fight to get your hands forward and up over your skis again. Suddenly you realize that you are hurtling ever faster down the chute and take notice of the trees coming at you. Instinct takes over and you initiate a turn to avoid the trees but being that you are tail gunning one of your skis twists uncontrollably away from you. Pop! There goes the weasel. Season over. And remember this all happens in less than a second.

That's pretty much what happened to me when I hurt my knee last weekend. I didn't even really fall. Got backseat on some steep stuff, tried to change directions quickly, tail got bogged down in wet snow or hit a rock, and boom.

[Dexter Rutecki]

My guess is that it is because some ACL injuries are the result of actual crashes where a brace could protect you vs. the typical backseat rearward falling deal that is so difficult to protect against.

I'm just having trouble envisioning such a fall (your first scenario), although I suppose it's possible--even so, I wouldn't think it would be statistically significant. But I believe a brace certainly can protect against some other knee injuries...The whole brace/non-brace issue is a big question mark for everyone, it seems (surgeons and people who do the studies don't have definitive answers, either). I wore a brace in the summer after my first ACL, but it was useless and I felt so much better once I got rid of it--having the brace actually made me trust my knee less, and it wasn't until I ditched it that I realized my new ACL was actually doing what it was supposed to do. This time, no brace at all, and I'm glad about that.
Both my crashes were simple impact, straight up and down, no twisting, so like I said, no binding in the world woulda helped, far as I can tell.

[Z]

quick question for you ppl in the know/huckers out there....do you ski your toe DIN higher/lower in relation to the heel? would it make any difference, or is there a theory/ideas to the differentiation (sp?)?

[summit]

quick question for you ppl in the know/huckers out there....do you ski your toe DIN higher/lower in relation to the heel? would it make any difference, or is there a theory/ideas to the differentiation (sp?)?

I ski higher on the tail.

[altagirl]

I'm just having trouble envisioning such a fall (your first scenario), although I suppose it's possible--even so, I wouldn't think it would be statistically significant. But I believe a brace certainly can protect against some other knee injuries...The whole brace/non-brace issue is a big question mark for everyone, it seems (surgeons and people who do the studies don't have definitive answers, either). I wore a brace in the summer after my first ACL, but it was useless and I felt so much better once I got rid of it--having the brace actually made me trust my knee less, and it wasn't until I ditched it that I realized my new ACL was actually doing what it was supposed to do. This time, no brace at all, and I'm glad about that.
Both my crashes were simple impact, straight up and down, no twisting, so like I said, no binding in the world woulda helped, far as I can tell.

It's just a theory - I have no idea on the statistics of what type of falls account for what percentage of injuries.

And as far as bracing I guess it depends on how the brace affects your skiing. I didn't ski with a brace at all after my first reconstruction. So that was like 200 some ski days with no brace - no problems and I was skiing way better than I ever did before surgery, but I did wind up with a torn meniscus after that. After the partial menisectomy my new surgeon insisted that I wear a Defiance for skiing. And it feels totally comfortable - I honestly forget it's there when I'm skiing (telemarking too). So I can't really see any reason not to wear it, even if it's just protecting against impact injuries and such. I'm getting a second Defiance in another couple weeks and he wants me to wear it for skiing (not that I can ski for a while...). Said it's up to me if I want to wear them both or just on the most recently operated on knee. No idea yet how that will feel, but we'll see. I think I'm going to wear them both for downhilling. (I heart body armor. )

And I do know what you're talking about with learning to trust the new ACL - I remember going through that with my first post-op mountain biking fall and realizing my knee was tougher than I thought it was.

[BakerBoy]

quick question for you ppl in the know/huckers out there....do you ski your toe DIN higher/lower in relation to the heel? would it make any difference, or is there a theory/ideas to the differentiation (sp?)?

I run 1 or 2 DIN higher on my toes.

[Z]

thats what i would think....for backseat landings/slaps where your mostly pulling on the toe...

[Spats]

Spats: Are you talking about Solly consumer bindings? I'm pretty sure my 916s don't have the spheric toe, the the wings are metal. They don't really flex at all.

Yes, I'm talking about the 810/912/914. The 916, being metal and an older design based on the 977/997, is much more stable. The ZZ S-Lab version has none of the Spheric stuff at all, just a regular AFD. The regular 916 appears to have the older version of Spheric, but without handling one I can't really tell.

I still think the Look design is better, but the 916 is a solid binding.