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Turn Transition Discussion - Page 2

post #31 of 45
nolo,

When you are skiing on one leg do you begin an extension before your ski is flat? This is my point. If begin to extend while on your uphill edge (one ski skiing or two ski skiing) is your transition smooth and fluid? or are your hips/Com projected up and away from the new turn???

"Versitile" to me is a much broader term than "efficient"... my goal is to ski efficiently, if I screw up, I hope I am versitile enough to regain my balance and exposure to continue on without falling.

In a turn transition, Do we begin to move our CoM across the skis THEN begin to extend? or Do we begin the extension first then begin to move our CoM across? I believe there is a primary difference and the timing of these two planes of motion are critical to EFFICIENCY of the turn transition.
post #32 of 45
Bud, wouldn't you say that what constitutes efficiency is somewhat dependant on our objective, and that we pursue many different objectives from turn to turn as we ski? To me, this also is where versatility comes into play. Plus, like Nolo, I like skiing in wide range of ways just for the fun of it. Just for the challenge.

Why do we climb the mountain? Because it's there.
post #33 of 45
So when does inside ski bias happen? Is it at the beginning of the turn, as in the White Pass Lean as Rick explained it? Transition completed on old stance ski before weight shift? Or is inside ski bias a tactic that is not needed/useful in most ski turns?

Bud Heismann, though you seem a bit rigid in your thinking, your argument makes sense and is well presented. I think there is something to Rick's idea that pressure can shift independently of balnce point. At the end of a turn (after fall line) centrifugal and gravitational forces are both acting on CM in downhill direction. A pressuring of inside ski will most likely only slow the downhill movement of CM, it never could actually move the CM uphill. Maybe if it is seen as a way to control movement of CM to a more constant speed. From the transition to the fall line, CM moves ahead of skis, after fall line skis catch up. Just a thought.
post #34 of 45
telerod15,

Quote:
I think there is something to Rick's idea that pressure can shift independently of balnce point. At the end of a turn (after fall line) centrifugal and gravitational forces are both acting on CM in downhill direction. A pressuring of inside ski will most likely only slow the downhill movement of CM, it never could actually move the CM uphill. Maybe if it is seen as a way to control movement of CM to a more constant speed. From the transition to the fall line, CM moves ahead of skis, after fall line skis catch up. Just a thought.
I agree
post #35 of 45
Quote:
if the trajectory of the extension movement is not in sync with all the physics and forces we have not optimized the transition.
I'll buy that, Bud, whether on one ski or two.
post #36 of 45
Quote:
Originally Posted by Rick
Bud, wouldn't you say that what constitutes efficiency is somewhat dependant on our objective, and that we pursue many different objectives from turn to turn as we ski? To me, this also is where versatility comes into play. Plus, like Nolo, I like skiing in wide range of ways just for the fun of it. Just for the challenge.

Why do we climb the mountain? Because it's there.
Well, I don't know if our interpretations are the same? If the objective is to extend like a tree grows on the uphill edge and interrupt a smooth crossover, then yes I agree. But why and in what situation is this productive? Granted it is how many skiers ski (even many level III's, unfortunately) but that doesn't make it efficient? does it?... Sure a diverging step turn where we delay the edge change to gain a higher line may be the objective may be palatable. If the intent is to change the rythme of the turn shape and delay the crossover...O.K. I can see that. Certainly, even in this task there is a limit, if the edge change to the BTE does not occur before the leg extension is complete from the uphill ski there would be an interruption in a smooth crossover.

I don't know? Can you give me an example of where we can "efficiently" make a turn transition without the CoM moving inside the new turn (inside edge engaged on new outside ski) before any extension is complete or a change in support foot (more than 50% bias) has occurred. I just can not visualize efficiency in the same turn as a vertical (like a tree grows) extension? Am I missing something?

thanks
post #37 of 45
Quote:
Originally Posted by Bud
When you are skiing on one leg do you begin an extension before your ski is flat? This is my point.
A Very precise question, but I think Bud has an unspoken (implied) constraint which he envisions but is not mentioning. Perhaps the vertical aspect is being evaluated in isolation? If nothing else happens in the lateral plane then he's right.


For the following perspective, slope-angle would mess things up so assume skiing forward on flat ground...

With no Lateral Activity - At turn transition the one-ski skier who increases the distance between CM and BoS before the ski is 'Flat' must be moving their CM toward the center of the old turn. At flat, the CM would move straight up - neither toward new or old turn. If extension is after a Flat ski, CM moves toward the new turn center.

Fine, no-brainers there.

But as we just chatted about in the Ankle Power thread we can easily make deliberate (or passive) lateral movements during transition.

I suspect our turns nearly always include an unconscious lateral adjustment of Feet vs CM during transition. For one-ski skiing we can thrust our single foot toward the old turn center making no extension at all - the new turn still starts because this effort moves the CM away from the old turn.

Timing of the extension is therefore not the sole determinant of CM flow regardless when edge change actually occurs.

If we adjust the rate of leg-extension (appropriately) to a particular rate of lateral CM movement then extension of our sole supporting leg to lift our CM can be done before, during or after the 'Flat' ski, and still keep the CM moving downhill.

Rate of lateral foot adjustment in combination with leg extension determines whether the CM moves 'uphill' or not.

So without ANY lateral adjustment (passive or active) of the CM then Bud's view of CM moving uphill can apply. It's just not what we all typically do.

Quote:
Originally Posted by Bud
If [you] begin to extend while on your uphill edge (one ski skiing or two ski skiing) is your transition smooth and fluid? or are your hips/Com projected up and away from the new turn???
The bolded part of the quote seems to suggest continuous balancing over his edge which implies he's not envisioning any lateral movement at all during his proposed extension. In this context, CM moves uphill.

The rest of us are all adding in some unconsious lateral movement - ignoring his implied constraint.

As far as optimizing goes I think it's the rates of lateral CM adjustment, leg extension and rate of edge change combined that will determine the efficiency of the transition.

Bud, might this be where communications are going astray?

.ma
post #38 of 45
Quote:
Originally Posted by telerod15
Bud Heismann, though you seem a bit rigid in your thinking, your argument makes sense and is well presented. I think there is something to Rick's idea that pressure can shift independently of balnce point. At the end of a turn (after fall line) centrifugal and gravitational forces are both acting on CM in downhill direction. A pressuring of inside ski will most likely only slow the downhill movement of CM, it never could actually move the CM uphill. Maybe if it is seen as a way to control movement of CM to a more constant speed. From the transition to the fall line, CM moves ahead of skis, after fall line skis catch up. Just a thought.
I can understand that "pressure can shift independently of the balance point" not an issue. I think I can see what you are saying....and I agree weight bias can shift from foot to foot near the turn completion without visually noticable moving the CM uphill; However, should there be any kind of extension on that uphill ski edge of the uphill ski the bias has shifted to >50% and this movement has in effect moved the CoM away from an "efficient" path (in a series of linked symetrical turns).

It would seem the efficient path would be to begin the change in support bias somewhere after the fall line while the CoM is moving closer to the feet toward the edge change but that the extension movement would include the edge change/crossover before that extension were completed insuring enough pressure could be applied to the inside edges to decamber them before the skis reach the fall line.

My focus is that in the range of "efficient turn transitions" ..."the crossover must begin before any extension movement" OK maybe not the rigid 50% bias but something close.

The classic days of extending to lighten the skis at edge change are dead don't we agree??? (not needed, not efficient) The more contemporary, efficient movement is to cross (cm to inside new turn) then use the extension to bend the skis before the fall line?? Sure all movements should remain in our repitoire but efficiency has evolved a bit maybe?? Modern technique has moved toward the extension/retraction end of the spectrum as a baseline.
post #39 of 45
Ma,

Aha! thanks, good point!

Can we agree that the more range of extension used off the inside edge the more we can bend and pressure the new outside ski? The longer we linger extending on the uphill edge the farther we move toward a longer radius turn.
post #40 of 45
Quote:
Originally Posted by michaelA
As far as optimizing goes I think it's the rates of lateral CM adjustment, leg extension and rate of edge change combined that will determine the efficiency of the transition. .ma

Agreed!!

This blend of movements is a spectrum

flexion/extension movement<-------------->extension/retraction movements

would anyone agree that modern ski design has moved our average turns more toward the right side of this spectrum??

I'm feelin it, you feelin it??

We still need the whole spectrum in our repitoire but efficiency seems to be a bit more to the right from say 20 years ago...?
post #41 of 45
Quote:
Originally Posted by Bud
Well, I don't know if our interpretations are the same? If the objective is to extend like a tree grows on the uphill edge and interrupt a smooth crossover, then yes I agree. But why and in what situation is this productive? Granted it is how many skiers ski (even many level III's, unfortunately) but that doesn't make it efficient? does it?... Sure a diverging step turn where we delay the edge change to gain a higher line may be the objective may be palatable. If the intent is to change the rythme of the turn shape and delay the crossover...O.K. I can see that. Certainly, even in this task there is a limit, if the edge change to the BTE does not occur before the leg extension is complete from the uphill ski there would be an interruption in a smooth crossover.
Bud, here's my view.

There are multiple concepts of efficiency. Balance efficiency,,,, efficiency of muscular involvement,,,, structural efficiency,,,, edge application efficiency,,,, CM path of travel efficiency. It's seldom possible to achieve maximum efficiency levels simultaneously in all areas. Often we must sacrifice ultimate efficiency to achieve a specific objective, and the particular need/desire for each turn dictates which efficiency area we must override.

As an example, lets look at balance. The most efficient state of balance is through the foot balance, with no leg leveraging against the boot upper. Here, pressure is distributed across the heel, big ball, and small ball,,, and the body weight causes the trusses of the foot to compress and provide a natural balance platform. It also provides the best opportunity for skeletal alignment, and the least muscular supplementation.

But we sometimes want to move our point of balance away from fore/aft neutral. Such as when we move our CM forward to intensify the arc at the top of the turn, or move back at the end of a turn to speed the exit. Both efficiency sacrifices to achieve a specific objective.

How about structural efficiency? The more countered we get the more our structural strength suffers. But staying square does not always provide for efficient balance. So here we must make a choice; one efficiency area must be granted priority. And knee angulation? Big structural weakness, but sometimes we need to use it.

And how about the efficiency area you mentioned; the path of the CM down the slope. Just as you suggest, any uphill movement of the CM constitutes a disruption of the CM flow. You provided a very good example of a legitimate purpose for degrading that efficiency. Stepping at the end of the turn requires an uphill movement of the CM, but it provides a bit of speed generation, or an end of the turn radius reduction that may be deemed worthy of the sacrifice.

Your second example was good too. During long, sweeping turns we don't want to quickly dive into a new high edge angle. Rather, we want to roll off the old edge and into the new turn slowly, and apply higher degrees of edge gradually. Efficiency dictates we just transfer pressure and let the external forces of the turn do the work for us, but we can slow down the natural transition process by moving our balance point and CM slightly uphill before the pressure transfer.


Quote:
I don't know? Can you give me an example of where we can "efficiently" make a turn transition without the CoM moving inside the new turn (inside edge engaged on new outside ski) before any extension is complete or a change in support foot (more than 50% bias) has occurred. I just can not visualize efficiency in the same turn as a vertical (like a tree grows) extension? Am I missing something?
I think you may be envisioning a more radical extension occurring during ILE than actually happens. It takes very little extension of the inside leg to create a pressure transfer from the old outside to old inside foot. Once the pressure transfer has taken place the extension remains very subtle, creating a constant state of pressure on the old inside ski until the edge roll over has occurred, and the new turn forces start to emerge and reestablish balance. The tree doesn't reach maturity until later in the new turn.

I think, from what you write here, that you envision a big tall extension on the uphill edge of the old inside ski. It's not the case. It's just a first move difference (ILE vs OLR) that achieves the same thing, pressure transfer. The advantage is in the superior feel for turn initiation and edge development ILE provides. The sacrifice is a bit more muscle involvement.
post #42 of 45
Thanks Fast, I can see clearly now! I was making the wrong visual assumptions in my head. I can visualize what you are saying and agree.

You know, rereading all the posts here I truly believe we are all on the same page! Trying to establish points of reference in a moving picture with so many combinations of movements and forces and transitions in pressure, edging, etc. make us trip over each others mental images.

If we all watched the same video of the same skier making the turn we envision in our own minds I think they would be pretty much the same!
post #43 of 45
While alot of this exemplifies that one of the beautiful things about this sport is the variety of ways that there are to go left and right. It also reflects upon the concept that intent dictates technique.

I hope folks delving thru this discussion are intrigued enough with some new thought or perspective to go out and explore the various blends described and determine Why to choose What blend option When it will support their skiing intentions.

The more ways you can move with intent to produce a variety of outcomes you desire, the more you will ski in sync with the mountain instead of in opposition with it.

Most great skiers all possess skill employing the same variety of blend options, even though their preferance may have a bias to one blend in particular that produces a feeling they enjoy and reflects their own their personal style.


Hey Bud,
Sometimes I like to ski 100% on my uphill ski edge even as I carve toward the falline on it, just because I can. : If this blend doesn't actually float, at least it at least bobs up and down like it is having fun.
post #44 of 45
Hey Arc!!! Good to see you again!

That's right........ I remember your demonstration at Big Sky!

I certainly have some fresh ideas to experiment with as soon as the lifts open. I hope we can make some turns together this Season!
post #45 of 45
Bud,
For me a good transition is seamless. Initiation, shapeing,completion all flow together and trying to identify when one begins and the next ends is imposable.
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