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Is Knee angulation bad? - Page 4

post #91 of 95

Cool!  Thanks for the explanation.  I just ski, and am not much of an analyst of the biomechanics.

Originally Posted by justanotherskipro View Post

If you think about it Cirque, during the last third of a turn don't we want the body to migrate towards the next turn? So, as wierd as it may seem, in that phase the skis are getting flatter to the snow and high siding is actually a welcome outcome. In fact, it's an essential element in the dual paths concept and cross over transitions. It's also part of Barnes' swoopy, foot squirting, transition clinic.As well as Harb's conservation of momentum ideas. It comes down to remembering our objectives at different phases of a turn. If it's one turn to a stop high siding would be an unwanted outcome, if we are linking turn it's a welcome outcome. 


post #92 of 95

You're welcome Cirque. I agree that bio mechanics and physics can be boring.

post #93 of 95
Originally Posted by justanotherskipro View Post

Ankle angulation? It's a hinge joint fellas, stop trying to invent new terms based on your incomplete understanding of human anatomy. Inversion / eversion and pronation / supination of the FOOT occurs below the ankle joint. Try Wiki if you need a refresher on how the ankle and foot move.


Let's remember the knee is a hinge joint and we talk about knee angulation don't we??  Actually the ankle is a little more complex than a simple hinge joint.  More of a saddle joint with gliding joints underneath.  This permits, depending on the skiers midfoot mobility, quite a range of motion possible.  Remember pronation is a combination of three planes of motion, plantar flexion, eversion, and abduction.  Supination is a blend of dorsi flexion, inversion, and adduction.


I have heard the argument many times that the foot/ankle can not angulate or twist but it is an easy fact to prove!  Take your shoes off and extend your leg out on the sofa.  Point your toes toward the ceiling and imagine a center line drawn down the middle of your foot.  Now simply invert and evert your foot as far as you can and notice if the center line moves right or left.  Now try twisting your foot as far as possible left and right and notice how it inverts and everts.  Do these two tests look pretty much alike?  I think they do and argue they are biomechanically linked movements.  Is this angulation?  Call it what you like but I believe it is angulation and no matter how tight my boots are making this movement inside my boots produces very favorable results.  The boot amplifies the strength of these internal movements to transmit impulses to the ski and better align the line of force over our working edges.

post #94 of 95


Cirquerider wrote:
. I think Knee angulation as well as ankle flexion are tools to modulate edge control, and is something many good skiers use subconsciously, and expert skiers consciously use to  to great advantage.


I think Cirquerider really hits the nail on the head with this comment/definition.


"Is knee angulation bad?"  Of  course not.  Possibly a better question would be, "how much knee angulation is needed and when is it need in relationship to the location of the turn"?  I'd say it depends on the desired outcome.


I believe angulation is generated by the varied rotation of 4 components, hip/knee/ankle/foot and is used to gain/develop edge angles (tipping), vary or tighten the turn radius and facilitate fore/aft edge pressuring (torque).  Generating angulation is all about creating, loading and controling edge pressure and angles so the ski will turn. 


BTW, really good thread here.  I think the reason the comments are so varied is that "generating angulation" is quite variable and the amount and combination of mechanical movements is really dependent on the desired intent/outcome/need of the turn. 


As seen in the OP's video, generating knee angulation early in the turn results in higher edge angles in the high C and increased pressure to the shovel edges which tightens the turns radius and shortens the arc length.  The shovel edges are hooked up throughout the turn, but the tails are brushing at the bottom of the turn.  If the skiers added more ankle rotation/extension and foot twist throughout the turn, the radius would be even tighter and the arc length even shorter, which would result in a "rounder" turn where their bodies stayed more in the fall line and the skis would come across the fall line quicker and at sharper angles.


I'm  way out of my league when it comes to racing gates, but it looks to me, when comparing Ted to Bodie, Bodie is slightly late at the gate as his skis are still leaving the fall line, where Ted's are already returning.  I believe Bodie is seen generating knee angulation here and probably rolling his ankle to in an effort to develop torque to increase shovel edge pressure tighten the turns radius.







bud h wrote:
I have heard the argument many times that the foot/ankle can not angulate or twist but it is an easy fact to prove!


I agree and there is no doubt the ankle can angulate.  I think the ankle does 3 things, it rotates, angulates and flexes/extends.  I refer to it as "rolling" the ankle over, but i admit that description over simplifies the movements and we can see any of them, which makes describing these vital movements so difficult and understanding them so complex.


I could never execute this turn in this location without knee angulation, a lot of it is certainly not "bad thing" in this instance and I could never get my skis to come across the fall line this sharply down the backside of a mogul without ankle angulation either.




Edited by Nailbender - 3/24/11 at 12:38am
post #95 of 95

Hi Bud, the point I was making was the joints below the ankle are largely responsible for the lateral movemtents you mentioned. I would add that standing on the foot and rolling the ankles laterally produces a different outcome because the talus and distal end of the Tibia are laterally displaced, not the sole of the foot. Ergo the commonand quite descriptive  medical term; rolling the ankle(s). Beyond that I agree that regardless of what we call it, the move is important for exactly the reasons you mentioned. If I could ask, you deal with posted and non posted footbeds on a much more regular basis and I would love it if you could comment on how this effects our lateral RoM inside the boot. Thanks in advance for your contributions. 

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