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Attempt for alternative view on 180 pivots

post #1 of 9
Thread Starter 
I am trying to get a better understanding of slow 180 pivot dynamics. I would like to use the clock dial to reference skier’s travel, where he starts at 12 and travels to 6 in clockwise direction. I understand that skier performs continues and gradual leg steering at all times through the pivot.
 
Usually, while performing movement analysis we are always looking at how body parts move or what moves first. To provide alternative perspective, I would like to take totally opposite approach and instead of looking at movements, take a look at multiple still shots of the skier taken during his travel from 12 to 6 o’clock.  I would like to analyze position/angle of skier’s skis, hips and shoulders in relation to fall line at every hour (12 o’clock; 1o’clock; 2 o’clock; 3 o’clock; 4 o’clock; 5 o’clock and 6 o’clock):
 
 
angle to the fall line
travel mark
12
1
2
3
4
5
6
skis
90
 
 
0
 
 
90
shoulders
45 (or 90?)
 
 
0
 
 
45 (or 90?)
hips
45 (or 90?)
 
 
0
 
 
45 (or 90?)
 
I will explain where this strange approach is coming from. Let’s take 12 o’clock:
 
It is obvious that skis are at 90 degree pointing across the fall line.
 
Though it gets confusing with hips and shoulders:
I know that upper/lower body separation should happen at hip sockets, which implies that shoulders and hips should be always at the same angle to the fall line. I would like to get a confirmation that 180 pivot is not an exception.
 
If hips and shoulders should be at the same angle to the fall line in 180 pivots, then what to do with the fact that skier should face the fall line (at 90 degree) at all times? It seems to be problematic for most people to keep hips parallel to their ski. Does that mean that hips/shoulders should be at different angle? May be 45?
 
Can somebody please help me?
post #2 of 9
Hi Stroller, 

I'll chime in based on my understanding of pivot slips.

Quote:
Originally Posted by stroller View Post

IThough it gets confusing with hips and shoulders:
I know that upper/lower body separation should happen at hip sockets, which implies that shoulders and hips should be always at the same angle to the fall line. I would like to get a confirmation that 180 pivot is not an exception.
 
Mostly, but likely not entirely!   

Quote:
Originally Posted by stroller View Post

If hips and shoulders should be at the same angle to the fall line in 180 pivots, then what to do with the fact that skier should face the fall line (at 90 degree) at all times? 
The best you can, given your range of motion.


Quote:
Originally Posted by stroller View Post
It seems to be problematic for most people to keep hips parallel to their ski. 
Yes it does!   

Quote:
Originally Posted by stroller View Post
Does that mean that hips/shoulders should be at different angle? May be 45?
I would say yes for almost everyone, but not 45deg.






Rocky, copyright Bob Barnes.

Ideally we could move like Rocky does without any windup in the torso.  I've not seen anyone that can isolate that well, but have heard its possible.



Ric Reiter, Pivot Slips

Ric shows the windup in the torso that typically occurs just at the end of the rotation in each direction.  So for most of the rotation, both the pelvis and shoulders face straight down the fall line.  At the very end (as the skis come perpendicular to the fall line) the pelvis will follow the feet around a bit (that tid bit is important ...the feet pull the pelvis around), while the shoulders continue to face down the fall line.  Likewise, the unwind toward the other side starts in the feet and legs, and the pelvis follows back to facing down the fall line until the legs reach their limit on the other side pull it around a bit at the end again.  

Does that help?

Best, 

Chris
 
post #3 of 9
Thread Starter 
Bump
post #4 of 9
 Chris, Bob, and Ric are my mentors on pivot slips.

Since I am sitting on my sofa and have not really looked down my body when performing pivot slips to note pelvis positions throughout the pivot slip sequence, I can only speculate here.

I would venture that my pelvis plane remains very closely the same as the plane between my ski tips?  In other words if I were to draw a line between my ski tips it would match the line connecting my illiac crests, while my shoulders would remain a bit more countered which probably aids the pivot initiation?
post #5 of 9
Thread Starter 
Cgeib, Bud,
 
Thank you very much for answering my questions! This topic is very important to me! I hit the wall with this task. I was able to do it moderately well from the very first time it was introduced to me 2 years ago and I was not able to improve ever since then.
 
What do you think about vertical extension that Ric Reiter does to unload his skis to start the steering? Is this vertical extension necessary? Unavoidable? Acceptable for level II exam? Do we need to unweight our ski to start steering?  Are there other, applicable to this task ways to unload the ski? (Directional move will not work in my opinion because we can not make it strong enough without tipping skis to opposite edges)
 
If unweighting of the ski is necessary, do we unweight both skis equally or the inside ski gets unweighted more? Does outside ski get unweighted at all?
 
I would like to clarify what “windup” means? Are you referring to the moment when his ski start to steer towards the other side?
 
Are you sure that “unwind toward the other side starts in the feet and legs, and the pelvis follows…”?  Is that a possibility that the first thing that Ric moves is his pelvis and his skis follow? Otherwise, how in the world he matches his ski width with his pelvis so precisely?
post #6 of 9
 What can't be seen in the pivot slips Rocky is doing is the pelvic rotation that Ric is doing.  

That pelvic rotation had to be done, because of the change over in uphill/downhill skis.  Bud mentions the line drawn between the tips. That line will never be perpendicular to the falline, because the skis would be on top of each other.  Similarly, the hips don't reach 90 degrees to the falllne either.  Most peoples range of motion just won't allow that much femur in hip socket rotation.  It's clear to see that Ric does not get pelvis facing down the falline.  Go beyond your individual ROM limit and torque to be used for the next pivot slip turn actually begins to prematurely pivot the ski.  

We also have rotational ROM in the spine to create torque which can be used to power the coming pivot too, so shoulders facing the falline more than the pelvis is useful.  If the shoulders and pelvis faced the same direction, there would be no torque (wind up) in the spine, and it's potential to help power the coming pivot would be squandered.  Pivot power comes from the torque created in both the anticipated pelvis, and spine.  They work together to produce a pivot that looks effortless.  

Little unweighting should be necessary, and I see little of it happening in Ric's pivot slips.  Just flatten the ski by rolling them downhill (off edge), then skillfully use the torque you've developed to power your pivot at the precise speed you desire.  
post #7 of 9
Thread Starter 
Rick,
 
Would you please describe step by step with timing how to execute that pelvic rotation? I think it will be break through point for me in combination with pelvic plane to match the line between ski tips.
post #8 of 9

Hi Stroller, 

 

I do not believe there is any appreciable vertical extension taking place in Ric's pivot slips.  My thought would be you are seeing more global movement of Ric up and down in the video frame due to camera work, along with a bit of change in leg length to accommodate the terrain (uphill leg shorter than downhill leg due to slope pitch) vs an actual vertical extension.  Further, I would say there is no "unloading" of his skis and none necessary.  He is basically executing the exercise with his full weight on both skis all the time, however, weight distribution will change from foot to foot with slightly more on the downhill foot and approximately equal when both are pointed directly down the fall line.

 

Sorry, dunno what's acceptable for a LII exam. 


Quote:
Originally Posted by stroller View Post

...Do we need to unweight our ski to start steering?  Are there other, applicable to this task ways to unload the ski? (Directional move will not work in my opinion because we can not make it strong enough without tipping skis to opposite edges)


Interesting questions!  They suggest to me (though I could be mistaken) that you believe steering stops and starts, and also that the edges are set and released, during the exercise.  If we watch Ric and Rocky above, they slip continuously and never "set" an edge.  While they do control their rate of decent I would described them as "released" the entire time.  They are able to steer their legs continuously throughout the entire time, and are doing so (continuously and deliberately) even when held across the fall line while continuing to slip with a "pause" in the rotation.  Likewise, they could also stop, hold, and restart their rotation (in either direction) at any point - just like they do with their skis pointed across the fall line.  

 

The windup I am referring to can be seen in Ric's demonstration.  As Rick described, it occurs at the end of the rotation due to our limits in range of motion and the fact that our skis/feet reorient slightly as the skis come that last bit across the hill so that they are above/below one another.  During that last little bit of rotation, the pelvis is pulled around a tad toward the tips of the skis.  For me, I am able to freely rotate the uphill leg externally but cannot quite get there with internal rotation of the downhill leg without a bit of following of the pelvis at the end.  While the pelvis does follow the skis a small amount, the goal is to maintain its orientation facing down the fall line as much as possible with allowance for our range of motion.    

 

Yes, the rotation takes place in the legs.  The point, I believe, is to demonstrate simultaneous leg steering.*  Ric and Rocky are rotating their legs.  To me, Ric's pelvis unwinds that small amount to face squarely down the fall line with the rotation of the legs when reversing towards the other direction, but the rotation starts in the legs and is followed by the pelvis.  Might be just me, but I feel it more as a playing out of the anticipation created in the torso rather than that anticipation powering it. 

 

All that said, I think this rotation of the pelvis is getting too much press.  The objective is to rotate the legs like Rocky does with the position of pelvis stable and facing down the fall line.  

 

Got some video?

 

Best, 

 

Chris

 

 

 *Good info available in The Complete Encyclopedia of Skiing under Braquage and Fulcrum Turn.

post #9 of 9
Among the many goals of pivot slips is developing the skill to begin the maneuver with a simultaneous release of edges and steering of the skis without a pushoff or rotation of the torso.
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