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How to do pure leg turning? - Page 4

post #91 of 109
Actually, on downloading the video and seeing it frame by frame, you can clearly see Ric's femurs tipping at :03, :08, :14, :20 etc.
post #92 of 109
Note at :08 where his ski hangs up. Because it caught, it slows in relation to the turning of the leg, resulting in the tipping - as I noted yesterday. If the ski had continued rotating at the same rate as the leg - no tipping would have occurred. A similar, but to a lesser degree, occurrence takes place at :03.

This shows the real world reality of Ric reacting to and dealing with the changing surface underfoot while intending to execute just as Rocky does in his perfect world. Maybe we can send him up to get footage with BigE on that ice rink!

:03 & :14 are the same images. As are :08 and :20

Hope that helps!
post #93 of 109
Quote:
Originally Posted by joseph View Post
The pity of all this is, as I've said before, most skiers pivot plenty. Very few know their edges.
Indeed. I would suggest that a pivot slip, correctly executed, requires very accurate edging and fore-aft pressure control. In fact, it may require very little, if any, active pivot. By active, I mean creating the pivot with muscular twisting, rather than by allowing the pivot to happen by managing edge angle, pressure and balance. A skier attempting to pivot by pure muscle, as if standing in stocking feet on a hardwood floor, will be frustrated.

However, cgeib and others are correct - it is quite possible to rotate the femur while keeping the foot flat. And, if the hill is just right, maybe we can get a pivot slip while maintaining the cross-section of the ski perpendicular to gravity. The slope, if it's just the right slope relative to all the other variables involved, might conceivably take care of the edging, and the pivot slip will "just happen" if I keep the bases of my skis "flat." When I pivot-slip, this is, in fact, the ideal. But I don't kid myself that I'm actually keeping them perfectly flat, either relative to gravity or to the slope.

There is nothing about our physiology that forces our skis to tip onto their uphill edges when we rotate our femurs, although that certainly is the tendency. Any skier who has body slammed while attempting side slips can tell you that there is enough compliance in the complex system that is the body to allow the feet to rotate right past "flat" while slipping sideways and catch the downhill edges quite abruptly, thank you.

I believe joseph is correct, too, in that we manage edging - and manage it in a very careful and subtle fashion - in order to accomplish a pivot slip. The ski is rarely perfectly flat on the snow (we don't like body slams), but it has to be flat enough to allow the slip, and it has to change edges at just the right time.

When I pivot slip (and I don't claim I'm the best at this - this is just my approach), I can start from a standstill perpendicular to the fall line. I stand there and flatten my skis until they let go and start to side slip. A slight fore-aft pressure shift will allow the tips to drop. The transition through the fall line is tricky, since subtle tipping movements must continue smoothly through the point where the ski is flat. Continuity must be maintained to engage what will be the new uphill edges. Once again, fore-aft pressure management engages the edges just right so that the rotation continues but the edges don't engage enough to cause forward movement.

Now, maybe I'm doing it all wrong. Still, I contend that this is not an exercise in muscular rotation. And, although our feet can stay flat, they don't. It is an exercise in edge control to allow passive rotation. Note that, just as in high level skiing, the tips lead the way. The release is the same as a regular turn, but the complete edge change is late. There is no heel pushing. There is minimal muscular twisting. The skis twist by managing edging and pressure distribution and using gravity to do the work. The pivot-slip is (or should be, in my opinion) the essence of passive rotary.

As always, your mileage may vary. Be aware that this poster may be a compete idiot. Do not fold, spindle or mutilate. The management is not responsible. All information should be independently verified.
post #94 of 109
it's odd that a maneuver designed to showcase leg steering skills gets so misunderstood. Are there other skills involved? Absolutely! Edge releases and re-engagement happens, fore /aft changes to our stance happens, even a little foot to foot weight / load shifting happens. That does not mean that pivoting the skis by turning the legs is a passive action nor is it intended to be so during this maneuver. Again, the exercise is designed to showcase the legs actively steering the skis. The other skills are involved but only in a supporting role, not the primary role.
Can those other skill negatively affect performing pivot slips? Sure. Failure to release the downhill ski being one that immediately comes to mind. It causes the skis to go sideways across the hill. There shouldn't be much turn shape, if any happening. It's not a turning maneuver, its sideslips with a pivot, followed by another side slip. Which means when the skis are in neutral (edges disengaged) we are actively pivoting them so they face the opposite direction. Stop over thinking the details and losing sight of the overall objective of featuring leg steering to cause a 180 degree pivoting of the skis.
post #95 of 109

Truisms

Quote:
Originally Posted by justanotherskipro View Post
it's odd that a maneuver designed to showcase leg steering skills gets so misunderstood. Are there other skills involved? Absolutely!
I don't disagree, but honestly I'm just so tired of the same disclaimers. Of course, we use all the PSIA skills all the time: that's how they're defined.

So what?

Granting that truisms are (by definition) true, the question is what we're seeing and doing. As I watch Scott Mather, the primary movement pattern is obvious (and I wont' repeat it now 'cause I've said it before).

(Sigh.)

P.S. Please, nobody tell me yet again why the three-page explanations of an elementary balancing/joint movement are useful, blah. The really short, insightful explanations--those that I can repeat in front of my next class and makes the lightbulbs turn on--now those get me excited!
post #96 of 109
Quote:
Originally Posted by joseph View Post
I don't disagree, but honestly I'm just so tired of the same disclaimers. Of course, we use all the PSIA skills all the time: that's how they're defined.

So what?

If all tasks/exercises are bended (and they are to some degree) does it really matter what skill we chose to highlight in that exercise so long as we are clear on the intended outcome and what we are working on?
post #97 of 109
Thread Starter 
Interesting enough, I have been trying this in front of mirror from time to time, just never thought it as an exercise. Will make a better effort at it.

So many good advice from so many great people. Sorry I couldn't thank you guys one by one.

Quote:
Originally Posted by justanotherskipro View Post
Whoever, Here's an off snow drill that will introduce leg steering...
... On an aerobics slide or just in stocking feet on a hard floor (no carpet) turn your feet and knees inward and outward. Make the pivot point happen underneath your arch (not in the heel or toes). It should look and feel sort of like the Charleston dance move. Notice the feeling of the feet sliding as they pivot beneath the pelvis that is not turning? When you are comfortable doing this move, try turning both legs the same direction without turning the pelvis. If that is giving you trouble move the pelvis enough (slightly up or down) to facilitate a drop in pressure between your feet and the floor. As you become better at this reduce the amount of up and down motion but hang onto the feeling happening in your feet. This should help you gain a better understanding and feel for what is happening when you pivot the skis. Remember the fact that as a drill it isolates a move to allow you to practice it. Once out on the hill the slope will make it more difficult to do this maneuver. In direct contrast to the others who are suggesting a steep slope, I would say no. Releasing the edges and sliding sideways needs to happen in a place that is less threatening. Pick a place that you feel comfortable with and start with a traverse with an edge release and re-engagement. Follow that with some hockey stops. Then go on to a pivot slip to one direction, a straight run, and a pivot slip to the other direction. Eventually loes the straight run between the pivots. You really need to own that simple skill before moving on to steeper terrain, or more complex maneuvers like linked pivot slips, and steered short radius turns. (Oops, the anti steering camp is going to flame me for that last statement.)
post #98 of 109
John,
Yes it matters. The skills blend specific to pivot slips is part of the objective as defined in the movement descriptors. That's the bottom line here. Are you versatile enough to accurately perform the specific skills blend you are being asked to demonstrate?
post #99 of 109
Quote:
Originally Posted by Joseph
P.S. Please, nobody tell me yet again why the three-page explanations of an elementary balancing/joint movement are useful, blah. The really short, insightful explanations--those that I can repeat in front of my next class and makes the lightbulbs turn on--now those get me excited!
It's discussion like this with lots of detail and explorations that cause us to think up those 'Short, Insightful Explanations' you're looking for... Recognizing unseen relationships and realizing "what matters" (each in our own way) is where those short meaningful statements come from.

For instance, this post describes the nature of a twisting ski independent of muscular driven action. Once we understand such details it's far easier to come up with new ideas for lesson plans, drills and simple explanations.

.ma
post #100 of 109
Quote:
Originally Posted by justanotherskipro View Post
John,
Yes it matters. The skills blend specific to pivot slips is part of the objective as defined in the movement descriptors. That's the bottom line here. Are you versatile enough to accurately perform the specific skills blend you are being asked to demonstrate?
First, what movement descriptors are you using? there are a few and context does mater. The descriptor you use defines your perspective of the outcome of task (multiple outcomes are valid).

Second, this task has three different major aspect to the describer:
1 rotation of the legs under a stable pelvis and upper body

2 simultaneous edge release and tipping movements of the legs

3 proportional flexion/extension of all joints to remain centered

If all these are essential elements of this tasks then, couldn't one use this task to develop any or all of these skills in isolation or in blended form?

-Jonathan
post #101 of 109
Jon,
As you have noted, many different ideas have been championed by all the organizations represented in Aspen. Not many places can boast examiners and demo team from so many countries. I also worked for Katy and was lucky enough to go out Every Wednesday with her and Squatty before line up. One of the things she insisted on was while freeskiing we were all encouraged to pursue whatever style and discipline we wanted but when we were in uniform we needed to show (in her words) "Aspen's brand of skiing". Which is decidedly PSIA based. Even the influences from elsewhere need to be within the scope of what Squatty, Georgie, George, and the rest of the training staff were tasked with helping us develop. Which is why I went back through PSIA's exam decriptors as a reference for this discussion about pivot slips.

"Pivot slips demonstrate mastery (or lack thereof) of a variety of technical skills vital to contemporary skiing. Primarily, they highlight the ability to steer the feet and legs precisely and continuously, independently of the upper body, without the need for a platform/pushoff behavior or upper body rotary mechanics."*

Bob goes on to describe how they help develop "strong edging skills" and "a well centered and fuctionally open stance", along with "the ability to balance and perform on skis with released edges that mark the essence of the transition in contemporary linked turns."

Which says to me that those skills are involved but only in the context of helping us release and keep the edges of the skis disengaged enough to facilitate the pivoting movements. Ironically, it is more than likely that a "fail" during an exam would involve innappropriate use of these other skills. Or (in my words), an innappropriate skills blend. Which is why I agree with your premise that we need to focus on whatever skill is preventing us from getting the skis to release and remain disengaged during pivot slips. That being said, I also feel that we cannot represent that they are the primary focus of the pivot slips maneuver.

JASP


*(level 3 through examiner descriptors) on Pages 27 &28 of Who, What ,Where, Why, & How? A guide to understanding and performing the SKIING MANEUVERS of the PSIA-RM Alpine Certification Exams, by Bob Barnes and the Alpine Education Committee.
post #102 of 109
MichaelA,

PM's post is interesting. In particular:

Quote:
Originally Posted by PhysicsMan
The sideways drag is primarily controlled by the sidecut of the skis (wider tips dig in more than a narrow tail), and the fore-aft distribution of the pressure of the snow on the ski. If there is more pressure from the snow on the ski in some region of the ski, and if everything else is held constant, that region of the ski will experience more sideways drag. Thus, if you pressure your tips, they will experience increased sideways drag.

However (and, this is a very BIG however), sideways drag alone is not the issue. Redirection of the ski comes from a torque acting on it, and this requires consideration of the two lever arms involved.

The way skiers increase the pressure on the forebody of the ski is to move their CM forward. This makes the lever arm for the forebody sideways drag force shorter and increases the lever arm for the aft sideways drag forces. Move your CM all the way over the tip of the ski and there will be zero lever arm for the forebody sideways drag (ie, zero torque from the forebody), and a huge lever arm (and a large torque) from the part of the ski behind your CM. Thus, even with a wide tip, your tip will drift downhill faster than your tails.
The movement of the pressure forwards and away from center is responsible for the increased lever arm on the tails. So, just like a fulcrum with a long arm, it will take less absolute sideways drag to overcome the sideways drag on the tips.

So, this is the PMTS two-footed release:

The increased lever arm of the tail and low edge angles above fall line cause the tip to seek the fall-line.

Then, edge grip on the shovel takes over to pivot the skis about the balance point.

All done without active rotation of the femurs.
post #103 of 109
Quote:
Originally Posted by justanotherskipro View Post
Jon,
As you have noted, many different ideas have been championed by all the organizations represented in Aspen. Not many places can boast examiners and demo team from so many countries. I also worked for Katy and was lucky enough to go out Every Wednesday with her and Squatty before line up. One of the things she insisted on was while freeskiing we were all encouraged to pursue whatever style and discipline we wanted but when we were in uniform we needed to show (in her words) "Aspen's brand of skiing". Which is decidedly PSIA based. Even the influences from elsewhere need to be within the scope of what Squatty, Georgie, George, and the rest of the training staff were tasked with helping us develop. Which is why I went back through PSIA's exam decriptors as a reference for this discussion about pivot slips.

"Pivot slips demonstrate mastery (or lack thereof) of a variety of technical skills vital to contemporary skiing. Primarily, they highlight the ability to steer the feet and legs precisely and continuously, independently of the upper body, without the need for a platform/pushoff behavior or upper body rotary mechanics."*

Bob goes on to describe how they help develop "strong edging skills" and "a well centered and fuctionally open stance", along with "the ability to balance and perform on skis with released edges that mark the essence of the transition in contemporary linked turns."

Which says to me that those skills are involved but only in the context of helping us release and keep the edges of the skis disengaged enough to facilitate the pivoting movements. Ironically, it is more than likely that a "fail" during an exam would involve innappropriate use of these other skills. Or (in my words), an innappropriate skills blend. Which is why I agree with your premise that we need to focus on whatever skill is preventing us from getting the skis to release and remain disengaged during pivot slips. That being said, I also feel that we cannot represent that they are the primary focus of the pivot slips maneuver.

JASP


*(level 3 through examiner descriptors) on Pages 27 &28 of Who, What ,Where, Why, & How? A guide to understanding and performing the SKIING MANEUVERS of the PSIA-RM Alpine Certification Exams, by Bob Barnes and the Alpine Education Committee.
JASP,

I agree with you, and all those you mentioned. The reason behind my statements were that it is valid and important to understand that from a coaching point of view many exercises can be used to coach multiple skills and it would be a mistake to pigeon hole this task to simply one skill. As a general rule, does PSIA-RM use pivot slips to test the ability to rotate the legs under a stable pelvis and upper body? Absolutely! However, this does not negate the other benefits of this task. Railroad tracks, sideslips, hockey stops, leapers, double pole drag turns, statue of liberty turns, javelin turns, dolphin turns, leapers, all have primary skill foci but could be used to develop secondary skills if qualified.

Jonathan Ballou,
PSIA-RM Alpine Committee Chair
post #104 of 109
Statue of liberty turns?

Dolphin turns?

Thanks,
JF
post #105 of 109
Quote:
Originally Posted by 4ster View Post
Statue of liberty turns?

Dolphin turns?

Thanks,
JF
Dolphin turns are much like leapers (both skis leave the ground simultaneously at transition) but generally use more fore/aft movement to aid in the skis leaving the ground. You would usually use them to test extremes of fore/aft balance but could use them for a verity of other things.

Statue of liberty turns are when the skier holds their inside pole up in the air, pointed straight up and the outside pole down and at an angle in contact with the snow.

Skier then switches abruptly at transition.

Usually used as a lateral balance exercise for the upper body but you could use it for orther things as well.
post #106 of 109
Dolphins:

Leave the ground on the tails, and touch down on the tips. Like a Dolphin porpoising.
post #107 of 109
Thanks for the descriptions JBL & BigE. Sometimes different regions & cultures develop different names for the same things. For instance, when I first learned hop turns (speiss turns?), we called them wounded rabbits, which then morphed into hurt bunnies lol.
JF
post #108 of 109
Well said Jon,
My point was simply that there is a primary focus that we shouldn't lose sight of in our exploring how to do a maneuver. Didn't mean to imply a strict cubby that ignores the other skills. Are there more effective drills to use to teach edging and pressure control? Absolutely! Which is why in my advice to whoever I think you will see a progression with a strong focus on developing an appropriate edge release doing garlands and other drills before trying to refine their edging and pressure control in their pivot slips.
JASP
post #109 of 109
Quote:
Originally Posted by justanotherskipro View Post
Well said Jon,
My point was simply that there is a primary focus that we shouldn't lose sight of in our exploring how to do a maneuver. Didn't mean to imply a strict cubby that ignores the other skills. Are there more effective drills to use to teach edging and pressure control? Absolutely! Which is why in my advice to whoever I think you will see a progression with a strong focus on developing an appropriate edge release doing garlands and other drills before trying to refine their edging and pressure control in their pivot slips.
JASP
Absolutely.
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