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Vaulting: What Is It and Where Does It Happen?

post #1 of 21
Thread Starter 

OK.  So even if you've only skimmed the 5 page thread on Virtual Bumps, you probably noticed that more than once I tried to describe what felt like a virtual bump to me, aside from the virtual bump that is evident in the ski's tracks.  From the description I gave, I was told that I was describing Vaulting.

 

Here's a picture that I cropped from a video.  It isn't the best but you might be able to see what I'm talking about.  This is what I was trying to describe.

 

virtual bumps3.png

This is the link to the video.

 

 

http://www.vimeo.com/3371564

 

The problem with the pictures are I didn't get the skier at full extension on each side.  What you can see is that his upper body remains at pretty much the same height but his legs extend and flex.  So if I stood on each side of a real bump and then stood on the bump, without raising the height of my head, my legs would extend and flex as they do in a cross under turn.

 

This is what I was trying to describe and was told it was Vaulting.  So I have two questions:

 

1) Is this vaulting?

 

2) If it is Vaulting, could it be possible that during Vaulting from a Cross Under turn, there is a virtual bump present during the transition between turns, that is completely separate of the Virtual Bump that is present going through a turn (that was defined/described ad nauseum in the "Virtual Bump.....Real or Fiction?" thread?  Kind of the traditional Virtual Bump and Rebound relationship (i.e. when vaulting you will have the sensation of going over a virtual bump.)

 

Along with this, I thought that Vaulting was using you legs as the pole in a pole vault to raise you CM across your skis.  That sounds more like it would come from a cross over than cross under.  I don't get how my legs can be compared to a stationary pole when they are pretty much the major thing moving in a cross under.  In a cross over, my upper body is moving across my skis, right?

 

Ken

post #2 of 21



 

Quote:
Originally Posted by L&AirC View Post

 

 

1) Is this vaulting?

 


Yes...but if you take just the pictures you got there...you can see he flexed such that the effect is virtually nill....I cant see the video for some reason, but if in earlier, or later screen shots he is inclined further...then obviously while still minimising the effect through flexion his COM would be rising up....thus Vaulting.

Quote:
Originally Posted by L&AirC View Post

 

 

 

2) If it is Vaulting, could it be possible that during Vaulting from a Cross Under turn, there is a virtual bump present during the transition between turns, that is completely separate of the Virtual Bump that is present going through a turn (that was defined/described ad nauseum in the "Virtual Bump.....Real or Fiction?" thread?  Kind of the traditional Virtual Bump and Rebound relationship (i.e. when vaulting you will have the sensation of going over a virtual bump.)

 


If I understand you...yes Vaulting is separate, but can occour simutaneously with the VB.
 

Quote:
Originally Posted by L&AirC View Post

 

 

 

Along with this, I thought that Vaulting was using you legs as the pole in a pole vault to raise you CM across your skis.  That sounds more like it would come from a cross over than cross under.  I don't get how my legs can be compared to a stationary pole when they are pretty much the major thing moving in a cross under.  In a cross over, my upper body is moving across my skis, right?

 

Ken


Well, yes obvioulsy the vaulting effect is greater in a cross over then a cross under....which is one of the main reasons cross under is generally the preffered tactic for high end skiing.....but if you picture a WC racer with their hip just skimming the snow in the turn...now matter how much they flex in the transition, there will be some vaulting effect as they transition.

 

To help perhaps, keep in mind Vaulting refers to the effect on the path or line of the COM in transition......VB refers to the effect on the path or line of the BOS (Base of Support...ie skis...or feet) in transition.

 

post #3 of 21
Thread Starter 


 

Quote:
Originally Posted by Skidude72 View Post



 


Yes...but if you take just the pictures you got there...you can see he flexed such that the effect is virtually nill....I cant see the video for some reason, but if in earlier, or later screen shots he is inclined further...then obviously while still minimising the effect through flexion his COM would be rising up....thus Vaulting.

 

In other parts of the video, you see more inclination and the vaulting becomes obvious.  Maybe it's that during small radius turns vaulting can be minimized (or canceled out) by being able to raise your legs and skis, which would also lower your CM right?

 

As you go from small to smedium, to medium and eventually large radius turns, the ability to do this has gradually been diminished because of each individual skiers varying amounts to flex.  So where vaulting becomes visible is variable in each skier but you can pretty much pick right about where it will happen.  Your legs have approximately 1/2 and inseam's worth of travel so if during the turn, my butt is less than 15 inches from the ground (I have a 30" inseam) there is no way I'll be able to prevent vaulting but if it is closer to 20 inches off the ground, I have a shot at it.

 

So vaulting is merely your center mass raising over your base of support during the transition of the turn.  Right?

 

We are comparing what it happening to your center mass during transition to that of the center mass of someone pole vaulting from the point the pole locks into that little box thing, up to where their cm is over the little box thing (pole vaulter's transition).  Not the part where they are launched over the horizontal pole (which is where I thought vaulting was being compared to).

 

You realize this means that pole vaulters have a VB too.  More of a virtual hill!

 

Thanks,

Ken

post #4 of 21

Awesome skiing in that video!  

 

 

Thinking about this VB vs. vaulting.....perhaps an easy way to think about this could be if we keep tension in the down hill leg at edge change to maintain or increase pressure we create more vaulting and if we choose to absorb that force by flexing we are reacting  to minimize the forces created by the VB.  

 

I would think tactically that coming into the same turn we can choose to deal with the forces differently.  If we hold tension in the outside leg we are choosing to redirect the skis more strongly across the slope whereas should we choose to relax or actively absorb these same forces we are choosing to end that turn and begin a new.

post #5 of 21
Quote:
Originally Posted by bud heishman View Post 

 

I would think tactically that coming into the same turn we can choose to deal with the forces differently.  If we hold tension in the outside leg we are choosing to redirect the skis more strongly across the slope whereas should we choose to relax or actively absorb these same forces we are choosing to end that turn and begin a new.

 


Hey Bud, 

 

What would you think of adding a "pre-jump" (so to speak) as another tactic?  So, as you exit the control phase you utilize the impulse from the turn to project your center of mass in space and time so you flow right over the pole and the VB, and smoothly flow down the back side of both right into the next turn.  

 

You would still flex to keep from disrupting the center of mass with the base of support as SkiDude notes above.  So, it might not look markedly different to an outside observer.

 

????

 

Best, 

 

Chris

post #6 of 21

Hey Chris,

 

I think of that as the same as my last sentence?

 

"actively absorb these same forces we are choosing to end that turn and begin a new."

 

I think of active absorption as using muscular effort or "avalement"

 

and

 

passive absorption to absorb or "replemont" or a relaxation

 

as two different options to absorb the forces whether VB or actual bump.

 

Were you thinking something different?

post #7 of 21

 

Hi Bud, 

 

Wish I had more time here, but:  yes, I think a "prejump" is different in the trajectory of the CoM.  Say vs avalement or reploiment. 

 

I know you have it, so see prejump in Bob's encyclopedia.  So in a prejump the CoM goes up prior the bump/drop and starts its descent to coincide with (close to) the falling off of the backside; without it, the CoM starts its descent after the bump has fallen away.  Then imagine applying those images to the diagrams Ghost and SkiDude have presented showing the VB.  That's the 2D or up and down version - 1 piece.  Because of the prejump you would be falling with the slope on the backside of the bump and able to use your extension following your avalement to reach out into the new turn instead of needing to use it to reach down and maintain contact.  I suppose you could also employ avalement somewhat to start the CoM following the gradient downward as well to some extent.  

 

I like projection out of the turn better than prejump really, since prejump only works well to show the 2D - to me anyway.

 

Added to the vertical is the across the hill bit.  In 3D, I'm picturing a dynamic skier able to move their CoM across the hill (lets imagine Ted Ligety).  This changes the rate the gradient change takes place.  It would be relatively slower change than say a typical park and ride skier that would hold on too long inside and suddenly huck across their skis down the hill - though the dynamic skier could likely be traveling much faster across the surface.

 

Sorry for the rush, hope some of that makes sense.

 

Best, 

 

Chris

post #8 of 21

Bud and Cgeib,

 

I think both work!   Bud's flexion method permits our skis to follow the Virtual Bump's contour while the CM follows a more direct path with flexion avoiding the force otherwise transmitted. 

 

Cgeib's pre-jump method largely 'tosses' our CM over the Virtual Bump permitting both CM and skis to follow the VB's contour again avoiding any force being transmitted to the CM by the VB itself.

 

A straighter outside-leg from Apex to very late in a turn would progressively 'direct' our CM up and over the VB (over an extended period of time) so we'd perceive less 'up thrust' near the end of the turn because we already let some of that force be transmitted to our CM gradually. 

 

 

---

Regarding an actual Pole Vault...  As I see it only the early part of that process is Vaulting and the later part is 'Pole Rebound'. 

 

The early part of a Vault works as described by many here but at some given point along the way the Vaulting part of the effort has moved a jumper's CM to the highest point possible via Vaulting alone.  Somewhere in that zone the energy stored in the Bent Pole (by Gravity and the jumper's forward momentum being arrested) is released to propel them further upward (if they've timed it right) adding to their overall final height.

 

Unlike the rebound in a Vaulting Pole I don't believe rebound in our skis adds anything to our overall forward momentum because the stored energy is generally released in a direction largely perpendicular to our overall direction of travel. 

 

Of course, if an SL skier is simply jumping from edge-set to edge-set (side-to-side) then maybe we could say ski-rebound contributes a some energy in a lateral direction (the skier needs to get left and right rather quickly) - but the amount is dwarfed (by orders of magnitude) as compared to that delivered by the catapulting effect of the forward motion of their skis through a tightly curved path.

 

.ma

post #9 of 21



 

Quote:
Originally Posted by cgeib View Post



 


Hey Bud, 

 

What would you think of adding a "pre-jump" (so to speak) as another tactic?  So, as you exit the control phase you utilize the impulse from the turn to project your center of mass in space and time so you flow right over the pole and the VB, and smoothly flow down the back side of both right into the next turn.  

 

You would still flex to keep from disrupting the center of mass with the base of support as SkiDude notes above.  So, it might not look markedly different to an outside observer.

 

????

 

Best, 

 

Chris


Well, if you literally mean "pre-jump"...it wont work....because it does.   If you pre-jump, you skis leave the snow, and thus all turning stops....you are now just travelling straight, in what ever instantenous direction you were just before you got airborne....and as we know...if you go straight, you cant have a VB....this dependence on line is the reason for the adjective "Virtual" in the name....we control the size of the bump with our line....the better alternative is to ski dynamically, lay the skis over, rip the steeps, ie...ski a gnarly line...and just accept you will have significant VB and Vaulting effects to contend with....BUT as I think Bud was suggesting....we can mitigate these effects by flexing through the transition, and extending into the fall-line!

 

Just a final point....the VB and Vaulting effects, are part of what makes the sensations of skiing so pleasurable....so yes we want to manage it....but it would be a shame if they didnt exist.
 

post #10 of 21

Weighting in quickly before heading out...

 

I love it L&AirC!!! So, you thought you had a hard time asking questions and getting answers about VB's, hopefully more people will agree on what vaulting really is and isn't.... 

 

Vaulting has always involved some sort of gong over aided by and supported by an object. You vault over a handrail - approach the rail, place your hands on the rail and then use both the spring in your legs and the strength in your arms to clear the rail. Pole vaulting - you run with a pole, use the pole as an aid to increase the height of your jump...

 

So, why anyone ever wanted to use the word vaulting in skiing is beyond me... trying to describe something, but again, a very confusing choice of words. 

 

Here is a video of another "sport" that also uses the word vaulting... do you see any similarities?

 


 

Quote:
Originally Posted by L&AirC View Post

OK.  So even if you've only skimmed the 5 page thread on Virtual Bumps, you probably noticed that more than once I tried to describe what felt like a virtual bump to me, aside from the virtual bump that is evident in the ski's tracks.  From the description I gave, I was told that I was describing Vaulting.

 

Here's a picture that I cropped from a video.  It isn't the best but you might be able to see what I'm talking about.  This is what I was trying to describe.

 

virtual bumps3.png

This is the link to the video.

 

 

http://www.vimeo.com/3371564

 

The problem with the pictures are I didn't get the skier at full extension on each side.  What you can see is that his upper body remains at pretty much the same height but his legs extend and flex.  So if I stood on each side of a real bump and then stood on the bump, without raising the height of my head, my legs would extend and flex as they do in a cross under turn.

 

This is what I was trying to describe and was told it was Vaulting.  So I have two questions:

 

1) Is this vaulting?

 

2) If it is Vaulting, could it be possible that during Vaulting from a Cross Under turn, there is a virtual bump present during the transition between turns, that is completely separate of the Virtual Bump that is present going through a turn (that was defined/described ad nauseum in the "Virtual Bump.....Real or Fiction?" thread?  Kind of the traditional Virtual Bump and Rebound relationship (i.e. when vaulting you will have the sensation of going over a virtual bump.)

 

Along with this, I thought that Vaulting was using you legs as the pole in a pole vault to raise you CM across your skis.  That sounds more like it would come from a cross over than cross under.  I don't get how my legs can be compared to a stationary pole when they are pretty much the major thing moving in a cross under.  In a cross over, my upper body is moving across my skis, right?

 

Ken

post #11 of 21

Bud,

 

I'm not sure, but I always thought that in the French school, avalament was one bump and replement referred to more than one bump - same move of sucking it up, but more times in a row... minor point. I'll try to check it out to make sure. 

 

But I understand your point of active and passive absorption.

 

However, I do not think that they are the same thing as pre-jump. A pre-jump is more of an extension/push-off move - or just the beginning part of an extension.

 

All of these - active, passive, pre-jump though are used to minimize the effect of the bump. In non-bump terrain, similar movement patterns are used to manage the pressure of the turn. So, I'd say it's really all about pressure management - no bumps, vaulting etc. I'd vote for sticking with thinking about pressure management in the turn and how it will effect your edging and guiding of the skis. 

 

Quote:
Originally Posted by bud heishman View Post

Hey Chris,

 

I think of that as the same as my last sentence?

 

"actively absorb these same forces we are choosing to end that turn and begin a new."

 

I think of active absorption as using muscular effort or "avalement"

 

and

 

passive absorption to absorb or "replemont" or a relaxation

 

as two different options to absorb the forces whether VB or actual bump.

 

Were you thinking something different?

post #12 of 21



 

Quote:
Originally Posted by Cookie Bewley Hale View Post

Bud,

 

I'm not sure, but I always thought that in the French school, avalament was one bump and replement referred to more than one bump - same move of sucking it up, but more times in a row... minor point. I'll try to check it out to make sure. 

 

But I understand your point of active and passive absorption.

 

 

 

Originally Posted by bud heishman

 

View PostI think of active absorption as using muscular effort or "avalement"

 

and

 

passive absorption to absorb or "replemont" or a relaxation

 


 

Georges Joubert - "Teach yourself to ski" @ 1970 or so.

 

post #13 of 21

Visualize a pole vaulter.  Now,  visualize a rear wheel drive car driving down the road and having the front differential fall off and the drive shaft jamming on an a pothole or other suitably solid obstacle and the car's rear end vaulting up.  What those two things have in common is vaulting.

 

It is using your momentum in combination with the geometry of a supporting object to translform that forward momentum into vertical momentum. 

 

Without shortening the distance between your hips and your feet, you cannot cross over from one side of your skis to the other without vaulting.   Flexing allows you to cross above your skis without vaulting. You can flex enough to not vault, flex more and do a cross under, or flex less or even extend and do a cross over.  Flexing old outside leg and extending old inside leg during transition is possible.  Whether it's vaulting or not, and to what degree it is vaulting, depends on whether the net effect is a reduction or increase in your elevation with respect to your skis..

post #14 of 21
Thread Starter 


 

Quote:

Originally Posted by Cookie Bewley Hale View Post
So, why anyone ever wanted to use the word vaulting in skiing is beyond me... trying to describe something, but again, a very confusing choice of words. 

 

This is one of the things that has frustrated and exhilarated me most of my adult life; communication.  I've found that sometimes it is worth the effort to have people explain back to me what I explained to them (yes adults too).  Things don't only get "Lost in Translation", it could be everyday communication.  This is also why I love to communicate so much.

 

My confusion on the term vaulting being used in skiing was that I thought everyone was talking about the act of being launched through the air.  Now I understand that in the application we are talking about what the pole does to the point just before you let go of the pole.

 

Here is a video of another "sport" that also uses the word vaulting... do you see any similarities?


Yes but in the video, the "pole" changes location.  First it is the legs that flex and extend and then as the weight is transferred to the arms, the arms become the pole.
 

In Ken's head, vaulting has always included being air born with the intent of leaping over something.  In my next post, I'll point out why I got really confused.

 

Ken
 

post #15 of 21
Thread Starter 
Quote:

Originally Posted by Ghost View Post

 

 

Visualize a pole vaulter.  Now,  visualize a rear wheel drive car driving down the road and having the front differential fall off and the drive shaft jamming on an a pothole or other suitably solid obstacle and the car's rear end vaulting up.  What those two things have in common is vaulting.

 

I'm good with this now.  I've re-calibrated for the use of this term with regards to skiing. 

 

Without shortening the distance between your hips and your feet, you cannot cross over from one side of your skis to the other without vaulting.   Flexing allows you to cross above your skis without vaulting. You can flex enough to not vault, flex more and do a cross under, or flex less or even extend and do a cross over.  Flexing old outside leg and extending old inside leg during transition is possible.  Whether it's vaulting or not, and to what degree it is vaulting, depends on whether the net effect is a reduction or increase in your elevation with respect to your skis..

 

When I wrote what I did in the VB thread, I already believed everything you stated about the cross under/over to be true.

In the VB thread I wrote:

 

So the third type of virtual bump I'm referring to happens only during cross under turns so the real bump it would be compared to goes parallel to the fall line.  Picture someone skiing a ridge and constantly skiing from one side of the ridge to the other staying towards the top of the ridge.  They are skiing back and forth across a very long.  When you are doing cross under turns all the way down the trail, in addition to the virtual bump effect you feel in the turns you make you will feel a third bump because you are constantly extending, flexing and extending your legs from side to side "under" you.  If your head doesn't rise up any higher than when you are at the apex of the turn while doing this, your lower body feels everything it would when skiing the ridge line.
 

and your reply was:

 

L&AirC,

You have described Vaulting perfectly.  Your body will go up and over, if you go from inclined left to inclined right without flexing.  This may be like a bump, but it is not what we are talking about when we talk about the virtual bump.

 

I'm so misunderstood

 

So I'll chalk you and the rest of the folks thinking I was talking about Vaulting when I was describing a cross under turn, to me staying up to late at night and not being clear.

 

What I was trying to point out in that thread and I will here is that if you do a perfect short radius cross under turn, the chance of there being any vaulting is pretty slim (provided it us done within what you wrote about it and I added ).  I think there might still be some fore/aft vaulting but not any significant lateral vaulting.  Does that sound correct?

 

Here's my new test to point out where I think there is another VB:

 

Sit in a chair like a proper young lady would that is wearing a skirt.  Your upper body is upright, shoulder square to the front and your are probably leaning to the front slightly.  Your legs are together, flexed at the knee and your feet are on the floor on the left side.  Your knees are probably a little lower than your hips. Your feet are pointing to the same direction you are looking.  You might have to scoot to the front of the chair to do this, especially if the skirt I know you put on for this, is a little too short.

 

Now, while sitting up right and facing forward, keeping your feet on the floor, slide them to the right side of the chair directly under your knees.  You will notice that your knees came up a bit during this transition from left to right.  You might have to watch them to see it.  Small virtual bump.

 

If you happen to be in s swivel chair, do it again but leave your feel on the left side and spin the chair to the right while your feet slide.  No bump.

 

Do the same thing but this time, instead of sliding your feet, just move your knees from side to side - Vaulting. 

 

Please tell me that even if what I described isn't the way it is termed in skiing, that I'm correct in what I'm seeing.

 

Thank you and good night,

 

Ken

post #16 of 21

Yes, you got the vaulting down.  As to the VB, the knees go up, but the measurement for the virtual bump is not the cm or the knees, it's the feet, actually the floor, which doesn't go up.   As to the skirt, it doesn't match my hairy legs; I need a longer kilt.

post #17 of 21
Thread Starter 
Quote:
Originally Posted by Ghost View Post

Yes, you got the vaulting down.  As to the VB, the knees go up, but the measurement for the virtual bump is not the cm or the knees, it's the feet, actually the floor, which doesn't go up.   As to the skirt, it doesn't match my hairy legs; I need a longer kilt.

 

Ahhh.  We're so close.  Put your skirt back on, get in that swivel chair in your proper girl pose; feet on the left.  With you left hand (or whatever works) give yourself a push to the right.  Let your feet slide along the floor as before but while the chair is still spinning right, slide your feet to the right (will have to move your feet faster than your knees) until they are on the right side.

 

Does that feel like you went over a bump?  I don't believe in the traditional VB the feet actually go up, though it does feel like it.  Just as it feels like the snow pushes up.

 

And before you reply this time, please take off the skirt kilt.

 

Ken
 

post #18 of 21

Yes it does feel very similar, because although your feet aren't going over a bump, your knees do rise up and over your feet in a "vaulting" motion.

 

Although a virtual bump might not have your feet going up, they do stop going down which is still a bump.

_____________/\________ is a bump, and

\

..\

....\

.....---

.........\

...........\   is also a bump.

 

Here's another situation to consider.  Riding a bike on a perfectly flat parking lot making a quick and hard left -right combination of turns.

As you go through the change from left turn to right turn and from leaning hard left to hard right, you bum has to go up and over with the saddle, because the distance from the saddle to the wheels' contact patches doesn't change (well not by much).  The elevation of the bottom of the wheels is constant so there is (no change in it's rate of change of elevation (remains zero) and therefore) no bump.

 

Do the same thing riding down an inclined plane, however, and the effect is greater, because you add a virtual bump right where your saddle is vaulting you over the contact patches.

post #19 of 21
Thread Starter 


You had me at "Yes"

 

 

Quote:
Originally Posted by Ghost View Post

Yes it does feel very similar, because although your feet aren't going over a bump, your knees do rise up and over your feet in a "vaulting" motion.

 

Although a virtual bump might not have your feet going up, they do stop going down which is still a bump.

_____________/\________ is a bump, and

\

..\

....\

.....---

.........\

...........\   is also a bump.

 

Here's another situation to consider.  Riding a bike on a perfectly flat parking lot making a quick and hard left -right combination of turns.

As you go through the change from left turn to right turn and from leaning hard left to hard right, you bum has to go up and over with the saddle, because the distance from the saddle to the wheels' contact patches doesn't change (well not by much).  The elevation of the bottom of the wheels is constant so there is (no change in it's rate of change of elevation (remains zero) and therefore) no bump.

 

Do the same thing riding down an inclined plane, however, and the effect is greater, because you add a virtual bump right where your saddle is vaulting you over the contact patches.

 


First VB post 6/8/10 at 6:54pm

Your last post in this thread  6/19/10 at 9:22am

 

160 posts in VB and 17 in this one.

 

That was...

 

Easy Button.png

post #20 of 21

Would you want to restate the last paragraph of you letter

post #21 of 21
Thread Starter 
Quote:
Originally Posted by jbharstad View Post

Would you want to restate the last paragraph of you letter


Wrote it when I got my point across in THIS thread.


Edited by L&AirC - 6/21/10 at 6:14pm
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