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Deb Armstrong: Use of the inside leg to change turn radius

LiquidFeet

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....What opened the door for me was their emphasis on all activity starting low to the snow (transitioning by stepping to a soft uphill edge of the new outside ski, then sliding back and lifting the arch of the new inside foot as it rolls over), then letting activity move up the kinetic chain higher in the leg into the pelvis...

.....the movement described initiates in the rotation and tipping of the pelvis into the same alignment produced by a well-executed javelin turn. If I may, please let me re-post a static exercise we can do the illustrate how this activity occurs:

"The pelvis rotates in a diagonal alignment: The uphill, inside half lifts (along with the inside half of the upper body) and rotates around toward the outside ski opposite the direction of the ski tips. This is facilitated by sliding back the inside foot and lifting the inside of that arch (which, in turn, allows the inside knee to lift and cross over). The outside half of the pelvis tucks under and rotates back. If you try this connected series of moves while leaning against a wall. I think you'll find they all work in harmony."
....
@mike_m, I've just gone back and re-read your post above. I think that you are saying that the rotation of the pelvis is the cause of the knee-pointing.

@HardDaysNight, I'm responding to what Mike has posted and his descriptive words because he originally brought this issue up in the thread.

I still don't see the knee-pointing, and I've described carefully in posts upthread what I do see. You see it, Mike, and I'm still interested in how what you see jives with what I see.

But the pelvis rotation is clearly there. If the pelvis rotation is the cause of the knee movement across the chest, and seeing something about the knee in videos and photos serves as a tell-tale signal that the pelvis has rotated, then I have no problem with that. I can be blind to the knee-pointing and still affirm the pelvis business since I'm aware of that rotation from experience.

I also know that sitting that rotated pelvis down towards the snow is easy and will put the skier in the back seat. Been there, done that. These elite skiers we are discussing aren't doing that, but copycats attempting to look like elites can fall into this dysfunctional trap easily.

There are many things that a skier has to do with the body to get decent turns, and many of them no one ever talks about. I have found that there are trends in what gets verbal attention in the instruction world from year to year. Maybe this will become the year of pelvic rotation. Inside up and forward, outside down and back. Let's make a refrigerator magnet for that.
 
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mike_m

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HI, LF!

Yes, the key movement is in the rotating and tipping pelvis. If you try the static exercise I mentioned of leaning against a wall, sliding back the inside foot and lifting the inside of that arch (which, in turn, allows the inside knee to lift and cross over), the inside portion of the pelvis lifts as the outside half of the pelvis tucks under and rotates back. If you try this connected series of moves while leaning against the wall. I think you'll find they all work in harmony.

In regards a rotating pelvis low to the snow putting thew skier in the back seat, that is a common misunderstanding of the movement. If you drop your bottom back toward the tail, you are holding yourself up with your quads. If you are rotating and tipping your pelvis diagonally (uphill half of your body higher and ahead, downhill half lower and behind), you are actually lifting and pulling your inside half longer. There is no activity toward the back of your skis or dropping of your bottom.

Please try the wall exercise! You will feel no dropping activity.

By the way, are you coming to Big Sky for the National Academy? Love to meet you!

Best!
Mike
 

LiquidFeet

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Mike, you have met me. At the 2019 National Academy.
We talked, but did not ski together.
I don't know if I'm coming this time. No food??? I love those big meals.
And I can't pick my group leader? That is very disappointing.
And they won't connect singles looking for roommates. Financial bummer.
I may skip it, but I am still thinking about it.


Just to let you know, I do this movement of my pelvis already, and not just in high-edge-angle turns. And have been doing it for years. You must have missed reading where I said that. And you're right, no one talks much about this pelvis movement. I've wondered why not, again for years.

When carving, I bring my knee up towards my chest, keeping it as close to the inside armpit as possible. I do not allow it to go all knock-kneed, though, moving over towards the outside shoulder. I work on keeping it "pointed" at the inside armpit, but it ends up about mid-chest despite my efforts.

I've been working on getting that knee so high that my inside boot is level with and almost touching the knee of the outside leg. Got that going now, but not consistently on different pitches. I could use skis with a waist lower than 70 to speed that whole thing up for shorter turns, but so far I'm getting good turns with my MX78s. Love those skis.
 
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geepers

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@mike_m - more searched for answers here than making sermons so please bear with...

As you point out there's a considerable difference between having these guys for a week on snow and watching a 25 minute vid with a mix of on/off snow. So trying to resolve the difference in focus. After all vids tend to record for posterity - they even called the last series Legacy - and sincerely doubt their intention is to mislead the viewer.

From Legacy Part 2 Carving (so long turns):
On lifting the inside hip (and the inside knee to chest for that matter) Lorenz/Berger/McGlashan all have drills and pointer for that. There isn't a mention of across the body to the outside armpit however it's raise to chest so maybe that's close enough.
On hip rotation Lorenz doesn't have much to say. Berger/McGlashan emphasize keeping hips square to the skis. With drills confirming. One of McGlashan's drills involves holding poles to each hip so they point out in the direction the hips are facing and the aim is to keep the outside hip pointing in the same direction as the inside ski. (He's angulated with body inside so that lines up when square to skis.) He also states his reasons for this - if the hips are countered (to the outside of the turn) then it is more difficult to tip the feet and eventually the outside foot will supinate . If over-rotated (into the turn) then tendency is to weight the inside ski.

The issue with countering seems correct as can be demo-ed at home - in an athletic stance it gets progressively harder to tip the feet as we move rotate away from hips square to the feet. (And the less said about over-rotation the better.)

Now doing the exercise you suggested leaning on a wall to simulate a ski turn... it takes effort to stop the hips from countering to a certain extent when trying to keep the inside leg out of the way as would be the case if it was a sloping pitch and not a flat floor. It's actually very physically challenging to get large angles leaning on a wall since there is no centripetal force to balance against - can more easily get angles by leaning on a large soft exercise ball. In which case the floor does become an obstacle and the inside knee does need to lift somewhat across the body. (Which I feel resolves that issue.)

So I'm wondering if the hip rotation can be resolved by thinking of countering to a Goldilocks amount - enough but not too much to inhibit tipping? Or is it a timing / part of the turn issue. Square at the top of the turn (transition) and then developing a little counter as the turn progresses? Any guidance?
 

mike_m

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Geepers, in reply to two of your points:

If you watch Reilly or Richie, their poles are usually held low to the snow and angled out. The handles are basically attached to the sides of the pelvis. When the outside pelvis tips under and low, the outside pole basket aligns with the back of the outside-ski heelpiece and the inside basket is higher and ahead (as is the inside pelvis and the inside of the upper body). The pole touch, when used, becomes more of a pole push which is timed immediately after the calcaneus bone (the front portion of the heel of the outside foot) stings the snow to end the turn and the tail of that ski shapes the end of the turn. This alignment of the poles and pelvis maintains counter through the transition (which, of course, is in opposition to traditional pole-touch placement which can lead to closing of the upper body and rotation across the skis - a subject for another long thread discussion!).

In regard to the wall exercise and the effect of centripedal force, I am attaching a video from a highly regarded Italian coach. PSIA advocates the skier to "direct pressure to the outside ski." Few coaches explain an effective method to do so. I find the concept or resisting imaginary bungee cords attached to your outside boot cuffs, knees and pelvis to be an excellent way of accomplishing this, plus it ensures edge grip throughout the turn. Hope you enjoy it.

Best!
Mike

 
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geepers

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If you watch Reilly or Richie, their poles are usually held low to the snow and angled out. The handles are basically attached to the sides of the pelvis. When the outside pelvis tips under and low, the outside pole basket aligns with the back of the outside-ski heelpiece and the inside basket is higher and ahead (as is the inside pelvis and the inside of the upper body). The pole touch, when used, becomes more of a pole push which is timed immediately after the calcaneus bone (the front portion of the heel of the outside foot) stings the snow to end the turn and the tail of that ski shapes the end of the turn. This alignment of the poles and pelvis maintains counter through the transition (which, of course, is in opposition to traditional pole-touch placement which can lead to closing of the upper body and rotation across the skis - a subject for another long thread discussion!).

Mike, this for short or long turns?

Not sure I see much more than a very light pole touch in Reilly's long turns.



In any event the drill is this - pole on outside hip pointing along inside ski.

1641245847992.png
 

mike_m

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Hi, Geepers!

Pole tip alignment for the touch (push), when used, is the same for all turns.

The pole position drill is actually designed to actively maintain counter throughout the turn (particularly through the transition) by use of active rotation of the pelvis opposite the direction of the ski tips.

Best!
Mike
 

Rdputnam515

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Just did a few runs yesterday to test this out (because of this thread) lol

yes in fact without even thinking about it for me this happens. purposefully shortening your uphill leg by driving your knee across the body (kind like pedaling a bike) does in fact change your turn shape as described and for advanced skiers should be easy to grasp conceptually.

this is easy to feel and practice in long radius carves, transitioning to sharper more g loaded shorter turns.

never thought about it much before but it creates more extreme angles and Much better edge hookup and energy loading onto the ski.
 

Rdputnam515

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Just did a few runs yesterday to test this out (because of this thread) lol

yes in fact without even thinking about it for me this happens. purposefully shortening your uphill leg by driving your knee across the body (kind like pedaling a bike) does in fact change your turn shape as described and for advanced skiers should be easy to grasp conceptually.

this is easy to feel and practice in long radius carves, transitioning to sharper more g loaded shorter turns.

never thought about it much before but it creates more extreme angles and Much better edge hookup and energy loading onto the ski.
Into the DOWNHILL SKI. forgot to put that in there
 

anders_nor

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I've been playing around with this since the video, its a bit weird (after skiiing for 30+ years)

I feel the effect is bigger on flatter terrain with less speed, than steeper with higher speed? could be me not doing it right on steeper though, or to much of my slightly fatass on the outer ski.

I do feel like it moves more weight to outer ski, maybe to much at times?


either way, fun new stuff to tryout
 

mdf

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I got a chance to experiment with the inside knee when I finally had my first day on snow. It really works!

Typically when I'm trying to make tight carved turns, once I get all my weight on my outside ski, I hit an edge angle and turn radius limit. When I try to get tighter, I realize I'm just trying to "will" higher edge angles and nothing happens.

When I lifted the inside knee (with the rest of the leg working to keep the ski parallel to the ground), the turn "magically" tightens.

Here's what i think is happening: the inside ski and leg have a small but not-insignificant fraction of your mass. When you pulll it up it moves the rest of your body down (since internal reconfiguration can't change the total center of mass). As your body goes lower, the edge angle goes up by simple geometry.

I was surprised that it had such a large, obvious effect.
 

Fuller

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I like the analogy of "it's basically like walking downhill". I've been thinking about that for the last couple of days - it implies a commitment to the fall line in a way that wasn't present in my skiing before.

For me, lately, it's all about getting my hips up and forward and committing to that outside ski in a way that feels like I'm taking a big step downhill. Maybe after all these years I'm finally feeling "forward" when it counts.
 

geepers

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since internal reconfiguration can't change the total center of mass

:cool:

Could you please unpack that for me?

The center of mass is the unique point at the center of a distribution of mass in space. What is the total of such a point?
 

mdf

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meaning "of the total body". That's a bit of carryover from my work where I often compute dynamics of composite structures with rotary joints. Each piece has its own center of mass that add up to the total center of mass.

Internal forces can change the configuration but cannot change the center of mass.
 
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