Randonnee AT Ski Touring Boot ISO Standards


This post by WildSnow.com blogger  

Industrial standards are a mixed blessing (e.g., it’s required quite a bit of designer skill to keep Dynafit bindings and boots working well together while having the boots conform to the ISO standard.) Yet on the whole, our gear would be reminiscent of stone age eating utensils if we didn’t have agreement (informal or otherwise) among manufacturers to stick with certain standards

Thus, when we’ve got questions about the boot/binding interface — or just wonder the “why” of a given boot feature, we find ourselves frequently referring back to ISO 9523:1990, the “DIN” standard for “Ski Touring Boots,” (telemark boots have a separate standard).

What got me thinking about this is a recent question we got about someones Marker Duke bindings seeming to place damaging pressure on their boot’s heel shelf. Also, a few blogs ago we brought up the issue of toe wear from hiking in randonnee boots, and how thicker rubber could fix that. Thus, for “mission: summer blog” I figured publishing more equipment backstory would be a nice way to add something to the great knowledge bank.

Backcountry skiing boots.
Side view of ISO ski touring boot heel dimensions shown above. Somewhat common issues with AT backcountry skiing boots are things like the binding heel not closing when you step down, or the boot having vertical play once the binding is closed. If you get any of those symptoms, check your dimensions based on the ISO drawing above. For example, see that the vertical thickness of the sole heel is 32 mm +- 3 mm (measure by placing boot on a flat surface and measure up from surface. If your binding is acting funny and your boot is within this spec (many of ours measure at 30 mm) then look at the binding for problems such as having the wrong length or forward pressure set. If the boot is out of spec or at the extreme end of the range, then consider fixes such as grinding to reduce thickness (rarely necessary), or re-soling if your boots are worn from dirt hiking (likely).

Backcountry skiing boots.
ISO boot toe dimensions shown above (side view). One of our pet issues here is that most AT boots could have more rubber at the toe, where most wear happens while walking. As shown in the diagram, this would be easy to accomplish while sacrificing some rocker. Many soles could even be made overall thicker (most of ours measure at around 28 mm), but doing this can be difficult in the case of Dynafit bindings, as the amount of sole below the Dynafit fitting is critical in how the binding operates.

An update to ISO 9523:1990 is in the works. According to sources it’ll have nearly the same if not identical dimensions, but define a sole that has solid areas that work better with binding support points (AFDs). The new standard is 9523:2008 (later digits are the standard’s date).

Comments

47 Responses to “Randonnee AT Ski Touring Boot ISO Standards”

  1. Halsted July 21st, 2008 5:08 pm

    Lou,

    Gee, I can’t make heads of those drawings. Are they for some new part on the space shuttle??? ;-)

    Cheers,
    Halsted

  2. Lou July 22nd, 2008 5:57 am

    Both are side views, after you know that they’re fairly self explanatory. Compared to rando bindings, the space shuttle isn’t that complex (g).

  3. Altis July 22nd, 2008 1:49 pm

    I wish you’d published drawings those six months ago – would have saved me $40! Aren’t they copyrighted though?

    I often wonder why Dynafit didn’t define a hole in the middle of the sole so that the binding arms impinged on a hard bit of plastic instead of wearable rubber.

  4. Lou July 22nd, 2008 2:17 pm

    Altis, the original drawings have some kind of use restriction (not sure it’s really a copyright), but by excerpting them and adding graphic elements, they become a derivative work, especially since I didn’t publish the work as a whole but only a small part. That’s the way I understand it, anyhow. Of course IANAL… It’s a grey area, for sure.

    If necessary, I’ll just re-draw them.

    What happened that cost you $40?

  5. Altis July 22nd, 2008 2:34 pm

    I downloaded ISO 9523:1990 from ansi.org in March and this cost me $40. At the bottom of every page it says “Single user license only. Copying and networking prohibited.” I needed it because I was modding some Flexons for touring and needed to know the maximum thickness of rubber I could use. I reckon 6mm just takes me to the upper limit. However, I found the two forks on the heel of my Fritschi bindings pressed worryingly hard into the rubber. With a belt sander I soon put a big chamfer on the rubber. When house and work are a bit less hectic I’ll put up some photos.

    Of course, what I’d really like is to fit some Dynafit inserts. I have a few ideas but the Dalbello Virus will probably be out before I get around to it!

  6. Lou July 22nd, 2008 2:44 pm

    Yeah, a “user license” is different than a copyright. But either way, a derivative work mucks it up enough so I doubt that my sharing it is a problem. If so, if asked I’ll remove and make my own version.

  7. Wynn Miller March 5th, 2013 10:14 am

    Hey Lou, have you seen any data comparing injury rates among different bindings (e.g. acl tears for skiers using standard alpine bindings versus tech bindings vs. Knee binding vs. Fritschi; spiral fractures of tibia suffered by those using any of the aforementioned bindings)?

  8. Lou Dawson March 5th, 2013 10:25 am

    Wynn, nope. I’ll bet there is someone studying it. The crazy thing is that tech bindings are not DIN/ISO, but the common wisdom and experience is they’re just as safe as DIN/ISO bindings when properly adjusted and skied unlocked. If there is any difference in injury rates, it must be minuscule, again based on years of observation on my part.

    I’ve hurt myself a number of times on AT bindings, but never on tech type ones. I do know of people getting hurt on tech bindings. Some say they were using correct settings and I believe them, but others have told me they were either locked or had dialed up their release settings to the point they were meaningless.

    Lou

  9. Wynn Miller March 5th, 2013 10:45 am

    Thanks, Lou – One reason for my question is because Knee brand bindings make the positive claim that they mitigate ACL risk (because the heel releases laterally). Seems as if tech bindings share that characteristic.

  10. Lou Dawson March 5th, 2013 11:55 am

    I agree, but it’s just anecdotal. I’ve always been amused by folks who diss tech bindings because the “toe doesn’t release.” That really means nothing, how a binding is overall designed is what has meaning. In the case of tech bindings, they actually release at BOTH the toe and heel in a side (lateral) release. Very few ski bindings do that.

  11. Lou Dawson March 5th, 2013 11:56 am

    The folks at Knee Binding have a method of testing for knee protection safety release. I wonder if we could convince them to test some tech bindings? Lou

  12. Wynn Miller March 5th, 2013 12:00 pm
  13. Rick Howell March 5th, 2013 1:18 pm

    @ Wynn Miller: Vermont Ski Safety Research does NOT have a method to test valgus torque or resultant tibial-valgus torque — which is the type of peak load that needs to be measured when abduction forces are applied to the medial edge of the ski that cause ACL injuries — and thus the link to VSSR is moot regarding binding function pertaining to ACL injuries.

    Many AT bindings do NOT provide the resultant peak tibia-torque release characteristics that the ‘alpine’ binding standards require (the alpine standards are ISO 9462, 9465 and 11087), thereby reducing the margin of safety to protect the tibia. Further, the “lateral heel release, per se” that’s found on some AT-bindings (IN THE ABSENCE OF TUNE-ABILITY) will allow the ACL of light males and most females to exceed its elastic limit (135% elongation) in the presence of large abduction forces that enter the ski under (or near) the projected axis of the tibia — (generating Very Large valgus torque that takes the ACL past its elastic limit).

    I have the only fully-functional device in the world that measures applied abduction-force, tibia-torque, valgus-torque, and resultant valgus-tibia-torque together with skis, bindings, and ANY type of boots (alpine or AT) — and that’s why I know.

    Rick Howell
    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  14. Lou March 5th, 2013 2:53 pm

    Rick, thanks, but “many” has no meaning. I’m surprised you’d use that word with the rest of your astute language.

    Furthermore, I’d continue question your use of the word “many” as a good portion of AT bindings now available are alpine bindings with alpine DIN/ISO certification, such as the Marker and Salomon offerings. Duke and Guardian, for example.

    Regarding tech type bindings specifically, I seriously doubt that when adjusted to the same release values they are any more dangerous to the knee ligaments than the vast majority of alpine bindings.

    On the other hand, I would agree that _some_ AT bindings may be substandard in terms of safety release, especially older vintages.

    Lou

  15. Wynn Miller March 5th, 2013 2:58 pm

    Thanks for your comments, Rick — Do you know of any statistics published collecting hard data on actual injuries to skiers who used either tech or regular or bindings?

  16. Wynn Miller March 5th, 2013 3:03 pm

    BTW, Rick, do you know Peter Kidd, my old Geze rep?

  17. Rick Howell March 5th, 2013 3:34 pm

    @ Wynn: Yes, I know Peter Kidd quite well :)

    Yes, there is epidemiology on injuries in non-alpine bindings — but the ‘controls’ are deficient, so it’s value is limited … but I will get back to you with the most recent findings.

    @ Lou: My utilization of the term “many” is to mitigate litigation against me because my binding colleagues know which of their own AT bindings do not meet the alpine standards (they don’t have to meet the higher-level alpine standards).

    DIN/ISO does not “certify”: only TÜV “Certifies” according to the various DIN and ISO standards. I know because I’m co-author of several ISO and DIN standards — and I’ve invested way too much time at the TÜV lab in Munich (the only independent lab in the world that tests according to the ISO binding standards).

    Again, meeting DIN/ISO standards for AT bindings is not the same as meeting ISO alpine standards :) Many (sorry) bindings that merge alpine technology to AT utilization cannot meet ISO 9462, 9465 and/or 11087 (sorry to disappoint you, Lou, but that’s the way it is: see the data from each model’s test scores at TÜV).

    All tech bindings that provide functional lateral heel release have the possibility of mitigating abduction forces that generate valgus torque, which valgus torque directly produces strain across the ACL (but tech bindings with lateral heel release that is not adjustable cannot mitigate strain across the ACL that’s less than the elastic limit of the ACL for smaller-scale men and most women). Respectfully, Lou, when was the last time you measured tibia-valgus torque generated by abduction forces that were applied under (or near) the projected axis of the tibia? Again, respectfully, kindly (and sincerely) please stay within your knowledge-domain in order to maintain credibility. This is outside of your knowledge domain because there are only a handful of folks at the edge of the envelope with me on this topic at this time. You are invited to visit my biomechanics lab here in Stowe at any time and I will be pleased to invest several days of my time with you on this subject — because you are looked upon as someone who will need to know this information as the research becomes more and more diffused.

    As for the term “substandard” — again, the state-of-the-art for the ‘standard of care’ is precisely defined by the voluntary consensus standards (ISO, DIN, AfNor, Ö-Norms, and ASTM) … but all of those standards will be falling behind the state of the art in terms of industry-available technology during the forthcoming boom that will cause a positive ‘effect’ in the mitigation of skiing-ACL injuries across all binding platforms, world-wide. Performing actual measurements to test according to the standards provides the Real Facts as to which bindings meet which standards and which bindings meet (or exceed) the standards — or which bindings fail and are ‘sub-standard’ … again noting that the industry is about to jump-ahead of the standards on the subject of knee injuries.

    What we here in North America must come to do (as the Europeans have been doing for some time) is to look at the ACTUAL “certificates” issued by TÜV so that we know, definitively, which bindings meet which minimum IS)/DIN standards. Few people here in N.A. even know what TÜV is: this is our own bad to not know and access this basic minimal information that will have a huge effect on which products we utilize on-snow.

    :) :)

    Respectfully,

    Rick Howell
    Howell™ Ski Bindings
    Stowe, Vermont
    [http://www.howellskibindings.com]

  18. Lou Dawson March 5th, 2013 5:08 pm

    Rick, if you’d been reading this website you’d know that I know what TUV is, so please lighten up. When I say something like “DIN certified” I mean “certified toDIN standard whatever”

    I may not be a doctor and know medical terminolgy, but I know that the Salomon Guardian is TUV certified to ISO 9462. Duke by Marker is certified to alpine DIN standard as well. Oh, and the Fritschi Diamir Freeride is certified by TUV to both 13992 and 9462. Considering this, a huge percentage of AT bindings are actually certified to alpine binding standard.

    And as we’ve written here a thousand times, tech bindings thusfar are not certified to any standard whatsoever. We know that. We also know that other AT bindings are not certified to the alpine binding standards, but rather to 13992.

    It sounds like you’re current with your anatomy terms, but might need to track the latest developments in AT bindings.

    I’d add that I get you know much about this, but other people can learn and study and have a take. More, field experience and observation is valid.

    P.S, there are very few current AT bindings that do not have adjustable lateral release. Very few. Latest FIS standards for racing require bindings to have both vertical and lateral release, so the race bindings with no lateral release are fading away. Granted, as you allude to some of those don’t have _adjustable_ lateral release, but from what I’ve seen those are falling out of favor as well due to the obvious needs of different skiers for adjustable rather than fixed release values. Beyond ski mountaineering race bindings, I know of no current ski touring AT binding that doesn’t have adjustable lateral release.

    Lou

  19. Rick Howell March 5th, 2013 5:57 pm

    Kindly Lou,

    … lateral ‘HEEL’ release …

    I live here in Stowe: we do ski here.

    The field IS my lab.

    Further, because I apply biomechanics does not disavow the balance of my background.

    Kind regards,

    Rick Howell

    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  20. Lou Dawson March 5th, 2013 6:00 pm

    Fair enough. I’d love to visit you, with some tech bindings in my bag.

  21. Rick Howell March 5th, 2013 6:08 pm

    Lou, You are welcome to visit at any time (with an appointment, pls) — ‘and yes, pls bring whatever bindings you would like to test. Again, I will be glad to invest two days with you at my expense.

    Sincerely,

    Rick Howell

    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  22. Bar Barrique March 5th, 2013 8:57 pm

    After skiing for almost 50 years, and, experiencing binding releases many times as I have this tendency to falling, I feel that (Dynafit) tech bindings are very good at providing a safe release. I would think that other tech bindings based on this design would work similarly. My experience with “single pivot” type AT bindings is not as good. IMO the way the “heel” piece functions on a “tech” binding results in a multi angle release matrix that is safer than traditional single pivot bindings.
    Of course you can save your self quite a bit of grief by not “dialing” your bindings to unreasonably high release settings.

  23. Lou Dawson March 6th, 2013 6:34 am

    Thanks Rick, that would certainly be worth doing. I’ll let you know if I can ever make it happen.

    I enjoyed reading this bio of you:
    http://www.howellproductdev.com/probono

    The comment in the bio about how pre-release and durability problems are to the overall design of bindings is spot on, and rings especially true for alpinists! Durability has been an ongoing problem for many AT bindings over the years, and pre-release is an issue as well. Since the tech binding in particular conforms to no standards, the consumer has no way of really knowing their binding’s level of performance, other than word of mouth and personal testing. That’s a bad situation that is an unfortunate thing regarding how good a job all you binding guys did over the years to reduce injury rates of alpine skiers on alpine bindings.

    On the other hand, I’m well aware of how standards can stifle development. Interesting issues, again, thanks for all your work.

    Lou

  24. Scooter March 6th, 2013 6:54 am

    $1250, $750 for bindings Rick??? I wish you success in that endeavor.

  25. Rick Howell March 6th, 2013 7:05 am

    Thanks, Lou. Indeed, we might be kindered souls on those key issues.

    Thank you, sincerely. You do a fine job, too, with your information exchange.

    @ Scooter: The $1250 binding will be a Real WC racing binding with no compromise: It is being designed to drop directly into the WC racing circuit, directly. It is not for everyone — it may not be for you.

    The next model down (the $750) is kind-of like Don Lamson’s D2SHOE in cycling: the real deal from a botique-maker. It is also not for everyone — and it may not be for you, either.

    All products are not for all people. Model / sub-market segmentation is a Very Real aspect of consumer products.

    IMPORTANTLY, I find it interesting, Scooter, how you ‘glossed-by’ my $299 model (which is $100 less than all other alpine bindings with lateral heel release).

    Most importantly, none of my new Howell™ Ski Bindings will be available on the consumer market until Fall of 2017 — until they are fully-ready.

    :) :)

    Respectfully,

    Rick Howell

    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  26. Lou Dawson March 6th, 2013 7:37 am

    All, until we have an MBA and do a marketing and consumer analysis, it’s tough to know what people will buy in the future, if it’s even possible for anyone to make such predictions with any regularity… I wish any entrepreneur all the success in the world.

    Overall, what may be happening in the ski industry is people are realizing that to have things like bindings that really work and don’t fall apart, they might cost some real money. The cycling industry has proven that consumers will pay for terrific stuff. I believe that’ll easily transfer to the ski industry. Along with that, there will always be plenty of price-point product and sales for those on a budget. Best of both worlds.

  27. Wynn Miller March 6th, 2013 7:39 am

    How much does ACL surgery cost? According to one online source, “eHow.com,” “The average cost of ACL surgery depends on whether or not you have insurance. If you have insurance, the average cost is about $1,850 (ranging from $800 to $3,000). Some of the out-of-pocket expenses include hospital admission fees and co-pays. Naturally, the insurance company must cover the procedure. If you don’t have insurance, the average cost is $35,000 (ranging from $20,000 to $50,000).” Another source asserts the average is $2,339.43. Another source puts it at $10,326.
    Whether those figures include all costs is anyone’s guess — that’s how we do it in America, keep ‘em guessing — so here’s a comparo:
    “For many patients suffering from Anterior Cruciate Ligament (ACL) damage in U.S. and U.K., an ACL reconstruction surgery is usually very expensive. In such cases, patients opt to go in for an ACL repair surgery in countries like Mexico, India and Costa Rica. The cost for ACL reconstruction surgery in these countries comes at a fraction of the cost in the U.S. and U.K. Medical Tourism Corporation’s network of hospitals can provide you an ACL reconstruction surgery from $4,300 to $9,400.” http://www.medicaltourismco.com
    In Lithuania, it’s $4,650, “Half the price of Western clinics while equal medical materials and facilities are used in Lithuania and qualifications of medical personnel in most cases are even higher than in the UK or the USA. The ACL reconstruction price difference is only based on significantly lower average salary and taxes in Lithuania.” http://www.nordorthopaedics.com

  28. Lou Dawson March 6th, 2013 7:45 am

    What is more, it’s not always a successful surgery. Prevention is the key, indeed not expensive medical care. Tough to totally prevent, however. You can do an ACL just going hiking…

  29. Scooter March 6th, 2013 8:16 am

    Rick – as I mentioned I do wish you success in this project. While without seeing your binding I would imagine it is pushing binding technology forward. Obviously the pricing, which I understand might change before you bring these products to market, did surprise me. I didn’t mention the $299 2.5-7 DIN version as that price is equally as surprising as the other models.
    While I’m sure your binding innovation will warrant these prices, I would be surprised if the market will endorse these prices. Your bio certainly addresses any doubt that your binding technology will be tested, proven and legitimate. My statement was aimed at what pricing the binding market will accept which is certainly a different topic. Who knows though, the Marker Duke cracked the $400 price point, the Dynafit Beast might break the $1000 barrier next year paving the way for your products.

  30. Lou Dawson March 6th, 2013 8:19 am

    “Who knows” is the operative phrase.

  31. Rick Howell March 6th, 2013 8:42 am

    @ Scooter: As Winn might be suggesting — the ‘value proposition’ that I’m bring forward (that’s the difference in price between equivalently-targeted models and my products) will be FAR LESS than the substitution-effect-cost of ACL reconstructive surgery (noting that my future-products aim to greatly mitigate — NEVER ELIMINATE — skiing-ACL injuries).

    :) :)

    Rick Howell
    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  32. Scooter March 6th, 2013 8:42 am

    For markets 4 yrs in the future “who knows” is certainly true. 2yrs out I don’t think “who knows” applies equally…. Cost of building dictates cost of selling so sometimes the market is what it is. Sorry to stray off topic.

  33. Scooter March 6th, 2013 9:13 am

    Rick. I have heard the ” it’s cheaper than a new ACL” sales pitch. It is true without a doubt, but when you put a product that gets the job done well at say $200 vs. one which gets the job done really well at $750. The end consumer (the person with the money and choice) comes into play. Anything we can do to make sliding around on snow safer and thus more fun is great for the industry and it’s growth.

  34. Rick Howell March 6th, 2013 9:36 am

    @ Scooter: :) Agreed: That’s why there’s a 3rd-model @ $299 (pls refresh your web browser when on the Howell™ website to see this 3rd-model in the future line-up). Even that model down in the line-up has advanced and unique ‘Anti-Pre-Release™ features allowing full-retention at ‘DIN-chart-settings’: this is a technology breakthrough that does not presently exist on the market, anywhere. Finally, we should all be able to ski without elevated settings and without pre-release. I believe the proprietary technologies that will make this possible can be transferred by Howell™ Ski Bindings to future Howell™ AT and future Howell™ tech-bindings, too. All of this is presently in development at this time … :)

    Now, I need to get back to testing :) :)

    Rick Howell
    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  35. Wynn Miller March 6th, 2013 11:50 am

    Lou, when you wrote “there are very few current AT bindings that do not have adjustable lateral release. Very few. Latest FIS standards for racing require bindings to have both vertical and lateral release, so the race bindings with no lateral release are fading away.” — did you mean lateral toe release, or lateral heel release?

  36. Lou Dawson March 6th, 2013 11:59 am

    Lateral release. In the case of tech bindings that’s usually adjustable at the heel. Don’t get hung up on this. Tech binding do their lateral release at BOTH the toe and heel. That’s why they release so nice if you’re walking and forget to lock the toe. Lou

  37. Wynn Miller March 6th, 2013 12:09 pm

    Lou, I just sent you an email, to the sopris.net addy, which was rejected – what’s your email?

  38. Lou Dawson March 6th, 2013 12:11 pm

    Wynn, use the contact link at top of page. I haven’t used the Sopris.net email in years. Lou

  39. Wynn Miller March 19th, 2013 12:09 pm
  40. Lou Dawson March 19th, 2013 12:50 pm

    You can do your ACL barefoot and walking on the beech. Knee bindings is a good idea, but someone doing an ACL while using it is not exactly big news to me. Would be different if people were tearing up their knees on it right and left, but it sounds like it’s just as safe as any other binding, and perhaps safer. Lou

  41. Jon Moceri March 19th, 2013 8:37 pm

    This is a great discussion, and I’ll put in my 2 cents worth.

    First off, I’ve torn both ACL’s on separate ski accidents. I think these were the “phantom foot” types. I was in the back seat, falling and trying to stop.

    The first was repaired with a patellar tendon graft, the second was with the hamstring graft.

    I’ve done a few things to prevent further injury. Most important. I’ve participated in many lessons and ski camps so I’m not in the back seat. Now I stand up and ski very balanced. I ski the DPS Wailer 112RP with the Dynafit TLT5 Mountain boot with no problem. In fact, most skiers my age and ability level can’t keep up with me in the steep and deep.

    I also have the first generation of the Knee Binding and I’ve followed the drama of it’s development and release on Epicski.com for years. And I’ve skied the Knee Binding for several years without any problems. And I think its the only real improvement in binding design in decades.

    My current DPS 112RP has Dynafit bindings, as do my Blizzard Bonafides. I only ski on Dynafit bindings regardless if its lift served, side country or back country.

    I think Rick Howell knows his stuff and is the guy saying that the “Emperor has no clothes”, with regard to current alpine binding technology.

    I’m an anesthesiologist, and if current bindings had to be FDA approved, they would fail. They simply don’t prevent knee injuries.

    I’d love to see Dynafit, Plum…(Spademan) bindings tested by Rick, on his equipment. And I don’t care if they are certified by TUV, DIN, ANSI or the Pope. I want them to release before my ACL does. I don’t ski race at 80mph or huck 50 foot cliffs. But I enjoy spirited skiing and want some assurance that I can get away from my ski if I’m about to be injured.

    I skied Spademan bindings in the 1970′s. I was always in the backseat, fell all the time, but never hurt my knees. I remember all the innovated bindings of the time, but now, no innovation, except the Knee Binding. And maybe tech bindings. I have to admit, I like the idea of full lateral release at the heel. Isn’t that a major cause of ACL with the “Phantom Foot” induced ACL injury?

    And Rick, (and Lou) with the patents off the Dynafit bindings, I’d love to see you come up with an improved design. One thought. Make the toe pin boot interface attachment a larger diameter. That would make it easier to step in the binding.

    In the mean time, I’m headed off to Mustang Powder for a few days of epic powder skiing, with my Dynafit set up.

    Jon

  42. Wynn Miller March 20th, 2013 12:01 am

    Thanks, Jon

  43. SR March 20th, 2013 9:56 am

    As regards the mention of testing by Jon, one of my takeways from the comments here is that there is a chance that tech bindings, because of their lateral release at the heel, may to some extent help mitigate phantom-foot type ACL injuries. Testing could defnitely be helpful to give an idea where things currently are here for tech bindings, if someone is able to then release the testing data. If there’s some way to model how phantom foot forces are affected by the ski moving through soft snow, all the better.

    As far as knee injuries on any binding, even skateboarders tear ACLs, with a fairly unrestricted lateral heel release. The issue with skis is the phantom foot type injury, so it would be very suspect if bindings designed to address phantom foot injuries didn’t still see some skiers using them experience ACL tears from other mechanism. In practical terms, I think that means that jumping will always carry an elevated knee injury risk, along with other issues with it in a non-resort context.

  44. Wynn Miller March 20th, 2013 10:12 am

    One would think that Dynafit would test/keep data of the sort SR mentioned.

  45. Rick Howell March 20th, 2013 10:25 am

    With my equipment, I can uniquely test peak release with a metallic musculoskeletal system as follows: tibia torque; valgus torque; resultant tibia-valgus torque; tibia torque with the BIAD-preload that I select; valgus torque with the same BIAD-preload; and resultant tibia-valgus torque with the same BIAD-preload … all as a function of abduction force applied to incremental positions along the full medial length of a ski. This approach provides 2 envelopes that can then be compared (overlayed at the critical points along the length of the ski that cause ACL injuries due to Phantom Foot and Slip-Catch injury mechanisms) to the elastic limit of the ACL. I perform these test with product set for a 50th-percentile male because the best data on the elastic limit of the ACL pertains to a 50th-percentile male.

    These tests take approx 3-days to perform under ‘ideal’ testing conditions. Aside from Lou, I would need to charge for this work — especially because the test equipment took decades to dial-in has cost more than anyone could fathom in terms of both direct-costs and time.

    Based on my presentations at the international skiing safety conferences, it appears that I’m still the only one, world-wide, performing these tests — though I do know of one professor in Munich, Germany (funded by several other binding companies) who’s ‘racing’ to catch-up to me.

    I predict that as soon as a few of the other binding-companies start earnestly testing valgus and combined-tibia/valgus torque — Big Changes in binding technology will follow my lead (sorry about the hubris) in binding design, too.

    Respectfully :)

    Rick Howell
    President,
    Howell™ Ski Bindings
    Stowe, Vermont
    [www.howellskibindings.com]

  46. Lou Dawson March 20th, 2013 10:48 am

    Folks, we will make this happen…

  47. Jon Moceri March 20th, 2013 7:57 pm

    Lou, great! We need to make this happen.

    As my Boeing engineer ski friends always say, “one experiment is worth a thousand expert opinions”.

    And since I’ve donated two ACL’s in the past, I would be more than happy to contribute $$$ to a fund to support testing or development of a safer binding, touring or otherwise. Lou or Rick, maybe something like Kickstarter.com to raise funds for a new touring binding could work.

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Welcome to Louis (Lou) Dawson's backcountry skiing information opinion website and e magazine. Lou's passion for the past 45 years has been alpinism, climbing, mountaineering and skiing -- along with all manner of outdoor recreation. He has authored numerous books and articles about backcountry skiing and is well known as the first person to ski down all 54 of Colorado's 14,000-foot peaks, otherwise known as the Fourteeners! Books and free back country news and information here, and tons of Randonnee rando telemark info.

All material on this website online magazine is copyrighted, the name WildSnow is trademarked.. Permission required for reproduction, electronic or otherwise. This includes publication and display on other websites by whatever means. PLEASE SEE OUR COPYRIGHT and TRADEMARK INFORMATION.

Backcountry skiing is a dangerous sport. You may be killed or severely injured if you do any form of ski mountaineering, skimo randonnee and randonnée skiing. The information and news on this website is intended only as general information. While the authors and editors of the information on this website make every effort to present useful information about ski mountaineering, due to human error the information, text and images contained within this website may be inaccurate, false, or out-of-date. By using, reading or viewing the information provided on this website, you agree to absolve the owners of Wild Snow as well as content contributors of any liability for injuries or losses incurred while using such information. Furthermore, you agree to use any of this website's information, maps, photos, or binding mounting instructions or templates at your own risk, and waive Wild Snow its owners and contributors of any liability for use of said items for backcountry skiing or any other use.

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