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Slip or grip using rotary

post #1 of 8
Thread Starter 
In Peter Hoppock's article, "Do you slip or grip? to grow you need 'em both" in the Fall 2004 TPS, he discusses a "rotary movement" that doesn't sound "rotary" to me. I'd appreciate any thoughts you all have on it.

Originally Posted by Peter Hoppock
On the next run, begin the same vertical sideslip again. As you're descending, feel the momentum and gently begin to redirect the tip/fibs from the downhill side of the book cuffs to the front of the boot cuffs. "Gently" is the key word here. Without much effort your skis will, in the space of a few yards, find and hold their edges as you travel in a line across the hill in the direction of the ski tips. Practice this a few times in both directions to make sure you have a feel for it.

Why is subtlety so critical? Well, because in order for the rotary skills to win out--i.e., the tib/fib shift from side to front--no leveraging can insinuate itself into such a movement. (Just watch your tails slip out into an unwanted christie if leveraging occurs.) Note that this rotary movement does not require any "steering" or rotation of the tib/fib along its own access.
I am trying to understand how moving the slight cuff pressure of the tib/fib from the lateral cuff to the front of the cuff is a "rotary skill." I am also working on understanding how a "rotary skill" doesn't involve any rotation. :

Any insight very much appreciated!
post #2 of 8
Just a guess here, but I think the rub is that your adjusting how much your pressuring the front part of the edge, enhancing it's grip causing a greater force between the ski and snow further from the axis of rotation and hence playing with the amount of "rotary" torque involved. Moving the force forewards makes for a greater torque.
post #3 of 8
I always thought that article was confusing in spots. That quote is one in particular. I'm guessing what he is speaking of is the rotation in the hip to move the point of pressure on the ski over the uphill edges of both skis so that the edges engage and change the movement of the skis from sideways to forward. This is from the legs rotating in the hip socket, as there is some flex in the knee, even in a tall stance, so the motion has a rotary element to it.

His use of leverage is confusing too. My take here is that he is simply saying that a rotary motion of the legs can move where the com is pressuring over the foot, but if there is pressure of the leg against the boot cuff this same movement can turn into a rotary force to the ski and cause the edges to break loose and the ski to pivot. What do you think Steve? Later, RicB.
post #4 of 8
Thread Starter 
I think if the tib/fib isn't rotating about its own axis, then the femur can't be rotating, either (given that there's no vertical rotational axis in the knee). I think that the move is from tib/fib applying slight pressure to the downhill cuff to tib/fib applying slight pressure to the tongue. There may be a "rolling" of the pressure from the downhill cuff to the tongue, so perhaps this is what he means.

Frankly, though, I really don't get what he's trying to say. I'm still working on it, trying to figure out what the deal is.
post #5 of 8
So much for TPS "professional" publications. Half of people writing in it don't know what they're talking about, another half cannot explain it if their life depended on it. I read TPS for entertainment purposes only. I remember seeing a force diagram where all the forces acting on a skier were centered in the middle of the ski...
post #6 of 8
The quotation describes a reorientation of boot/shin contact from more lateral to more forward. He's calling the reoriantation a subtle "tib/fib rotation". If done gently and without an increase in forward pressure, the vertical sideslip turns into a forward sideslip and then an edge engagement "carve". If the reorientation results in an increase in forward pressure, you will leverage the tails loose as the shovel edges gain in grip. Personally, I've never done a vertical sideslip where I felt contact with the "downhill side of the boot cuff". I'd expect that to result in a shoulder plant. To me, the contact is with the uphill sides of the boot cuff. I think a far superior "subtle edging" skill drill is to do shallow traverses toward a target. "Normal" edging results in the skis turning uphill from the target. If you can maintain two crisp lines and not veer from the target, you are edging subtly.
post #7 of 8
Thread Starter 
I guess the good news for me is that this isn't evidence of me being a complete ignoramus when it comes to these things! Thanks, Kneale. I certainly get what you're saying!
post #8 of 8
I think what he is talking about is a subtle edging change and when we tip our edges we actually are rotating the femur in the hip socket.

stand up and flex your ankle and knee equally while tipping your feet and you will see your femur rotate.

If this is done while having your hips too forward this movement will cause tips to slip out especially the dh ski
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