Dorsiflexion and its role in skiing

Discussion in 'Ski School' started by LiquidFeet, Jun 2, 2019.

  1. JESinstr

    JESinstr Lvl 3 1973 Skier

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    There's a reason the Romans invented the Arch. They knew, that someday, they would be skiing.

    arch.jpg
     
    Last edited: Jun 5, 2019
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  2. Tony S

    Tony S aka qcanoe Skier

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    Why the absolutism? Not sure if it's intentional, but your phrasing has overtones all-encompassing stone-tablet knowledge. A lot of very experienced and talented instructors here - and a few interlopers like me - don't seem to think it's so simple.
     
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  3. James

    James Skiing the powder Instructor

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    Very interesting!
    Where did you find that?
    What is the _ mm = _ mm refering to? Second is deflection, what's first #?

    I think "heels" is a coaching cue for those getting too much on the ball of foot. I'll leave it to those who know about such things.

    ----------------------
    Principle #2: The Mid-foot Balance Point
    One of the most common technical mistakes in powerlifting occurs when lifters shift their weight onto their toes when squatting or deadlifting. The best way to correct an exaggeration in one direction is with an overcorrection in the opposite direction. Hence, some of the most popular “coaching cues” in powerlifting are “get your weight on your heels” and/or “push through the heels”. The contexts of these cues have been lost for whatever reason and many people have been led to believe that optimal technique actually involves being balanced on your heels. This is certainly not the case.
    ---------------------
    http://www.powerliftingtowin.com/powerlifting-technique-the-scientific-principles/
     
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  4. no edge

    no edge Putting on skis Skier

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    Great skiers change edge angles to control pressure, but using the whole ski to steer and control the pressure is an important aspect of great skiing. There is more to skiing than 'big toe little toe'.
     
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  5. elemmac

    elemmac AKA Lauren Skier

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    The first number is his measurement. In the first shot before loading the ski he shows "179mm = 0mm". So from there 183mm = 4mm (i.e. 183mm - 179mm = 4mm) deflection.
     


  6. Rod9301

    Rod9301 Out on the slopes Skier

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    Why not both?
     
  7. slowrider

    slowrider Out on the slopes Skier

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    Don't you usie your ankles to start and adjust these movements?
     
  8. JESinstr

    JESinstr Lvl 3 1973 Skier

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    This is what happens when we take a situation that is normally static (standing) and make it dynamic (moving). People try to justify dynamic situations with static examples.

    Not that there are not good points to be made.
     
  9. markojp

    markojp mtn rep for the gear on my feet Industry Insider Instructor

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    Forebody pressure, or edge angle? Ankles open, or closed? From the feet, or higher up the chain?

    greenpantski.jpg
     
  10. Mike King

    Mike King AKA Habacomike Instructor

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    Somewhere upchain someone suggested the goal was to pressure the fore body of the ski. Such a goal suggests that it’s (almost?) universally true that pressuring the tips is an objective. My understanding of ski performance is that pressuring the tips leads to displacement of the tails; I.e. the tails do not follow the tails same trajectory as the tips. There maybe times when that’s the ski performance you want, but most high performance skiing is not served by such ski performance. The video that @geepers posted shows what happens to ski shape and edge engagement when the pressure point is moved forward and aft of center.

    If the objective is to drift a turn, there are multiple ways to achieve that objective. Moving the pressure point is only one. But I’d argue that in most circumstances, keeping the pressure point in the center of the ski will be the route (and root) to higher ski performance.
     
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  11. HardDaysNight

    HardDaysNight Out on the slopes Skier

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    This is so good that, IMO, there’s not much more to say! Impressive guy that JB.
     
  12. no edge

    no edge Putting on skis Skier

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  13. Wilhelmson

    Wilhelmson Out on the slopes Skier

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    This is my rudimentary understanding. I think in our icy conditions some instructors still teach the shins to cuffs method to pressure the forebody to get the whole ski working, or maybe to over correct for back seat and other problems. They can only do so much in an hour or two and that might be a necessary evil to get a skier with worse bad habits using the edges on front 3/4 of the ski.
     
  14. no edge

    no edge Putting on skis Skier

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    I agree that pressuring the tips can lead to washout - especially if you are leaning against the front of the boot. But dorsiflexion allows a use of the front of the ski (and center) to do some great performance skiing... like tightening the radius of a turn, steering (!) which is an awesome sense of motion that skiing offers. Dorsiflexion allows for the use of the forward flex without needing to "pound" it. It also allows the skier to drop down without falling into the backseat. It's a fantastic skill but for me it requires proper boot flex.

    I should tell you that I not an expert in analysis or understanding the mechanics... as many in this tread may be. I could tell you that I am unqualified, but I do have a background in using dorsiflexion within a range of skiing. I do have limitations.
     
  15. James

    James Skiing the powder Instructor

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    In terms of the body, skiing is much more static than most sports. If one foot is a stride length in front of the other that would be extremely unusual. The feet and lower leg is encased in a device that severly restricts movement.
    How many beginners have you had that make 10x the move you want them to make?
    Skiing is almost slo motion movement, especially at the lower levels. A lot of the dynamics is estimating where to be and what to do in the next moment.

    It's one picture, but he's pretty centered.
    In ski boots, the ankle is pre dorsiflexed, closed. It's all relative.

    IMG_6525.JPG
    Sole Boot Lab, Chamonix
     
  16. Corgski

    Corgski Getting on the lift Skier

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    Firstly an edit for my previous post: I am a strong believer in skiing from the feet, my advice to relax feet was really only for those who have tried to use their TA to do all the heavy lifting as described in some posts. Relaxing feet will give your excruciating TA a break, shift some load onto your hamstrings and get you down your last run without calling patrol for help. Yes, I have tested it out, yes one's TA can really, really hurt.

    There is a difference between coaching cues and a working mental model of skiing that you can take on the hill with you. I have no issue with any of the TA coaching cues, but it is presented as a model and when taken that way it does not work. It assumes a particular problem which not everyone may have and it seems to assume complementary muscle activation which may or may not happen (credit to @François Pugh for the idea of complementary muscle activation). If you add a lot of context to what is written, the issues I have with it potentially go away.
     
    Last edited: Jun 5, 2019
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  17. Tony S

    Tony S aka qcanoe Skier

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    LOL. Imagine if this crew had to discuss tennis.
     
  18. JESinstr

    JESinstr Lvl 3 1973 Skier

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    JESinstr said:
    This is what happens when we take a situation that is normally static (standing) and make it dynamic (moving). People try to justify dynamic situations with static examples.

    Not that there are not good points to be made.
    While there is nothing in your response with which I disagree, This is truly a case of glass half empty/half full.

    The problem most instructors have with beginners is STOPPING the 10 x move that you DON'T want them to make. And the problem goes deeper that just moves IMO
    .
    Take for example, the moving walkway at the airport. You approach making fairly dynamic moves (walking and if your late for your plane, running). Your eyes input forward travel to the brain. You enter the moving walkway and cease the dynamic moves (stand) . Yet your eyes keep inputting forward movement to the brain resulting in a temporary (depending on coordination) impending loss of balance which most easily adjust to.

    For beginner skiers, it's just the opposite. They are standing still and suddenly, their eyes and other senses detect movement and much worse for the brain's survival component, acceleration. But wait, they are standing at 0x movement and the skis just started accelerating out from underneath. the length of the skis inhibit fore/aft dynamic adjustment. Call in 10x moves from the upper body to try and save the day. Bad move.

    IMO this is why I find this thread very interesting and important. For those of us who believe that we start at the foot, dorsiflexion or at least the concept thereof may be the key to getting beginners off on the right foot....excuse the pun.
     
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  19. Thread Starter
    TS
    LiquidFeet

    LiquidFeet Making fresh tracks Instructor

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    Might this video impact the discussion in some way?
    Note that the shield hangs and its lower edge moves fore-aft.
    PSIMAN's anatomy is different from ours... no ankles to dorsiflex.
    But, there are indirect similarities. [Also, I've heard that PSIMAN falls more often that this video implies.]
     
  20. Rod9301

    Rod9301 Out on the slopes Skier

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    When you pressure the tips, the ski bends more, so you shorten the turn radius.

    It's still a carved turn
     

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