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# Ski technique - Page 31

Quote:
Originally Posted by CTKook

A summertime analog would be doing laps on a pump track where you jump every roller -- both good conditioning, and your jumps get better, but obviously slow as well.

Going off tangent here (yes, pun intended), cool vid where inline skates are used on the pump tracks. Even the ice cross skaters say it's to build skill..... where did we hear that before.

Quote:
Originally Posted by The Engineer

I looked through that thread and a number of people had it right, but not Jamt as usual.  I have this technique where I can load the ski through a combination of rotary and tipping to create quite a bit of spring and jump from turn to turn.  I can do it with very little inclination and at slow speeds.  When the ski is bent it pushes back with a force that gives you an extra push when you jump.  You can feel the difference for different skis that are stiffer.  Jamt probably measured the force in the middle with the tip and tail held, saw a small value and ran with it, but you have to move the grip point further up.  Having the ski on the snow makes no difference, if the ski is bent, it's pushing back with force.  When a ski is bent in an arc on edge, it takes pressure to keep it there.  The "locked" edge doesn't hold it in that arc without body weight.  A ski with no snow under the boot can hold your weight, so that's how much force the ski is pushing back to give you a trampoline feeling.  It's a full time job trying to straighten out all of Jamt's bad physics which I don't have time for, so I'm not going to argue this for a thousand posts, but maybe at some point I'll start a new thread with some video, showing the technique and demonstrating the spring of the ski loaded in particular ways.

So you load a ski with rotary. That's just funny.

Edit, and to add. It has become quite typical that you attack the person rather than technical arguments.

Edited by Jamt - 1/1/16 at 8:19am
Quote:
Originally Posted by Jamt

So you load a ski with rotary. That's just funny.

Hmmm.

Quote:
Originally Posted by Jamt

....

Edit, and to add. It has become quite typical that you attack the person rather than technical arguments.

Quote:
Originally Posted by Jamt ...

...

Care to name a leading coach who claim that you should push off from the downhill ski and stay heavy through transition? And please, not the drivel from Phil [McNichol, former head men's alpine coach for the USST] when he coaches beginners....

....

Quote:
Originally Posted by Jamt

I admit I was wrong. Here is C. demoing a high end turn with weighted flat skis during transition:

The pattern of personal attacks, including attacking the former head men's alpine coach of the USST and his opinions as "drivel," is indeed clear.

Quote:
Originally Posted by razie

Quote:
Originally Posted by Pacmantwoskis

Quote:
Originally Posted by CTKook

But, it bore out some valuable facts about modern racing technique. Even for recreational skiers, the simple task of thinking about making overlapping cuts on one ski (or simply two skis) is a good takeaway that can help their own skiing, and be a helpful reality check on some of the odd technique advice that is more internet driven.

@razie,if Count Kook hasn't yet driven you to drinking, I applaud you.

There is no way he can seriously mean what he says.

It may be a self-fulfilling profecy and maybe that was the plan all along: The more I listen, the more beer I drink, the heavier I get and... oops???

Not to worry, more mass = more success on the DH (and more speed free-skiing).

Quote:
Originally Posted by ChuckT

@The Engineer, what you say about ski pressure needed to accelerate a skier along the slope and airtime is slow seems obviously correct to me. But here is what I can't reconcile (besides the numerous clips and pictures of WC skiers). Allow me to define "light" and "heavy" as the strength of the force component perpendicular to the slope pushing on the skier. We feel light and heavy as this force component decreases and increases, respectively. Regardless of my level or how I ski, the time-averaged value of this component must be my weight times the cosine of the slope angle, right?

Allow me to imagine I'm a studly racer. At some point I will be very "heavy" (more than w*cos(slope)).  Therefore, I must be "light" (less than w*cos(slope)) at another point. No? And shouldn't that light or lighter point be at the transition?

Before anyone asks, I hasten to say that I am neither a certified racer nor a practicing physicist. Just a passionate skier who still remembers high school physics.

Despite not being a certified racer nor practicing physicist, @ChuckT has learned what many skiers spend years skiing and never learn.  You only have so much into the snow force to apply in the bank, and you had better choose to spend it where it is needed.

Quote:
Originally Posted by CTKook

The pattern of personal attacks, including attacking the former head men's alpine coach of the USST and his opinions as "drivel," is indeed clear.

... you sure you want to go there? I fully agree with Jamt - do you want me to count the number of times you resort to personal attacks instead of technical arguments, to support your assertions, as a percentage of your posts?

How about instead, be civil and continue adding some amusement value by trying to misunderstand us this use of "heavy"... from another high level coach (and in fact forum member) that clearly doesn't want to stay "heavy" through transition, but rather absorb it by flexing and prefers to recenter by pulling the feet back:

cheers

Edited by razie - 1/1/16 at 12:00pm
Quote:
Originally Posted by The Engineer

The bent ski is like a spring board and does store some energy, like how a bow can shoot an arrow.

The amount of energy stored is small and no where near enough to launch a racer from one turn to the next.

Quote:
Originally Posted by The Engineer

Quote:
Originally Posted by Tog

Not much energy, plus there's usually snow underneath so it's no longer a bow. This was discussed in some detail in this thread like pg 4 on:
http://www.epicski.com/t/119963/why-be-patient-at-turn-transition/90
I looked through that thread and a number of people had it right, but not Jamt as usual.  I have this technique where I can load the ski through a combination of rotary and tipping to create quite a bit of spring and jump from turn to turn.  I can do it with very little inclination and at slow speeds.  When the ski is bent it pushes back with a force that gives you an extra push when you jump.  You can feel the difference for different skis that are stiffer.  Jamt probably measured the force in the middle with the tip and tail held, saw a small value and ran with it, but you have to move the grip point further up.  Having the ski on the snow makes no difference, if the ski is bent, it's pushing back with force.  When a ski is bent in an arc on edge, it takes pressure to keep it there.  The "locked" edge doesn't hold it in that arc without body weight.  A ski with no snow under the boot can hold your weight, so that's how much force the ski is pushing back to give you a trampoline feeling.  It's a full time job trying to straighten out all of Jamt's bad physics which I don't have time for, so I'm not going to argue this for a thousand posts, but maybe at some point I'll start a new thread with some video, showing the technique and demonstrating the spring of the ski loaded in particular ways.
I think you should throw down some calculations that qualified people could evaluate. Or maybe you'd see something else by doing it. How much energy do you think can be stored in the bent ski itself that gives you the jump?

A little thought experiment might help.  Work is force times distance.  How much work does gravity do to bend the skis that much when you step on them while they are suspended between two supports?  About as much as you do climbing up two stair steps?

A tiny bit of energy, but over 50 plus turns, with every bit helping it might add up to the difference between podium and also ran.  Same with pushing downhill at high c,  tiny but worth it when you can handle it.

Quote:
Originally Posted by Tog

I think you should throw down some calculations that qualified people could evaluate. Or maybe you'd see something else by doing it. How much energy do you think can be stored in the bent ski itself that gives you the jump?

Edited by The Engineer - 1/2/16 at 7:47am
Quote:
Originally Posted by razie

... you sure you want to go there? I fully agree with Jamt - do you want me to count the number of times you resort to personal attacks instead of technical arguments, to support your assertions, as a percentage of your posts?

You, too, have been very offensive. Just saying. It has seemed to me, impartial giggler at this thread, that you have consistently been the most antagonistic and needlessly ad hominem.
Quote:
Originally Posted by The Engineer

Yes, Razie, I gave you that out.  If you are defining heavy as the apex of the turn, then certainly the transition will be light.  Though, this is not what Phil or CTkook meant, because they know there is no centrifugal force during transition.  If it's a simple misunderstanding of words, then fine.  2/3 of maximum weight as a mean is heavy enough especially given that it's distributed.  We're not proving that every transition is heavy, only that some are.

Here's a quote from Rick posting right here on Epic, so you can see it's not just the people dumb enough to keep arguing with you that understand these things.

" Metaphor, for what purpose are you trying to unweight in the first place?

Up unweighting and down unweighting were pervasively used techniques in the pre shape ski days to allow the skis to be easily pivoted/redirected coming out of the transition (Pianta Su).  Now a-days, arc to arc turning is more feasible in more situations, and in those turns unweighting is not necessary.

And,,, just for clarity,,, release does not equate to unweighting.  OLR and ILE just transfer pressure from one ski to the other, they don't eliminate it.  Unweighting does eliminate it. That's it's purpose"

Razie, go lick your wounds and come back another day, and maybe you'll win next time, but this horse is dead.

A quick comment to this. It is true that with modern carving skis we do not need to up-unweight to turn. However, not everyone can carve their turns all the time and most people cant carve anyway. There is a huge market for up-unweighting waiting to be explored by masses.

Quote:
Originally Posted by tdk6

A quick comment to this. It is true that with modern carving skis we do not need to up-unweight to turn. However, not everyone can carve their turns all the time and most people cant carve anyway. There is a huge market for up-unweighting waiting to be explored by masses.

Yes, that technique I was talking about earlier that I love to do, I believe could be described as an up-unweight move timed just right to get assistance from the spring in the skis.

Quote:
Originally Posted by tdk6

A quick comment to this. It is true that with modern carving skis we do not need to up-unweight to turn. However, not everyone can carve their turns all the time and most people cant carve anyway. There is a huge market for up-unweighting waiting to be explored by masses.

By the way, I believe I saw you write in a thread about how down un weighting typically isn't just retracting the legs, and I agree with that.  It's very difficult to stand and just retract your legs to get much weightlessness to do much of anything.  I believe that most of the time when someone is unweighting there is some "up" coming from somewhere before retracting the legs.  First there needs to be some upward acceleration, then the legs can retract.

Quote:
Originally Posted by The Engineer

By the way, I believe I saw you write in a thread about how down un weighting typically isn't just retracting the legs, and I agree with that.  It's very difficult to stand and just retract your legs to get much weightlessness to do much of anything.  I believe that most of the time when someone is unweighting there is some "up" coming from somewhere before retracting the legs.  First there needs to be some upward acceleration, then the legs can retract.

Exactly. You can downunweight to even out rebound but not to initiate a turn from a traverse. And why do people claim ski stiffness has no impact on how much power you get out of rebound?
Quote:
Originally Posted by The Engineer

By the way, I believe I saw you write in a thread about how down un weighting typically isn't just retracting the legs, and I agree with that.  It's very difficult to stand and just retract your legs to get much weightlessness to do much of anything.  I believe that most of the time when someone is unweighting there is some "up" coming from somewhere before retracting the legs.  First there needs to be some upward acceleration, then the legs can retract.

Yes there needs to be some upwards acceleration, but you have already claimed vaulting is not taking place, which leaves pushing yourself up and the energy stored in the skis.

You do realize of course that as the ski untips on hard snow the height of the ski-boot interface gets closer to the snow so the stored energy cannot be used to get direct upwards acceleration. It could help in vaulting, but according to you it does not happen so that leaves pushing, but that is not down-unweighting. Hmm something does not add up.

Quote:
Originally Posted by Jamt

Yes there needs to be some upwards acceleration, but you have already claimed vaulting is not taking place, which leaves pushing yourself up and the energy stored in the skis.

You do realize of course that as the ski untips on hard snow the height of the ski-boot interface gets closer to the snow so the stored energy cannot be used to get direct upwards acceleration. It could help in vaulting, but according to you it does not happen so that leaves pushing, but that is not down-unweighting. Hmm something does not add up.

When I use the ski's spring to get more hop, it's up and to the side.

I never said vaulting doesn't happen.
Jamt - our skis, boots and lower legs, basicly everything below our knees is always vaulting back and forth as we tip and de-tip from turn to turn. However, in ref to gravity our lower legs vault naturally as we come through apex. Nothing we need to think about. So this effect is usually neglected. Or considered part of something else. Right?
Just a simple truth: Fast racers try to eliminate the float between turns. The reason is simple, and if you watch and listen to what Ligety says you'll see why, skis that are floating or light do not turn! The reason Ligety has such a fast transition is so that he can pressure the ski as early as he can. Becaus the skis have such a long radius 35m and he carves more than anyone he needs to start that carve sooner and can't afford to have a lengthy float phase. That is another reason he moves his weight to the inside leg and pushes on it as he rolls from the little toe edge to the big toe edge. That move allows him to absorb some of the energy, from the turning ski, in the leg letting him maintain some pressure through the transition. This is totally in line with what Phil is saying as well. I aslo remember have essentially the same conversation with Phil while I was coaching his son. The conversation was centered on getting athletes to move thier hips forward through transition by pushing on the uphill ski, he asid it was the number one deficiency he saw in athletes coming to him. We also spoke about maintaining pressure through the transition to allow athletes to start to shape the turn as soon as possible.
Quote:
Originally Posted by The Engineer

Vaulting is not the standard for high end racing.

Quote:
Originally Posted by The Engineer

When I use the ski's spring to get more hop, it's up and to the side.

I never said vaulting doesn't happen.

Right, but you basically said it is not used in high end racing. So what is causing the upwards acceleration?

Please explain how the ski pushes you upwards when it comes closer to the snow when untipped.

Quote:
Originally Posted by tdk6

Jamt - our skis, boots and lower legs, basicly everything below our knees is always vaulting back and forth as we tip and de-tip from turn to turn. However, in ref to gravity our lower legs vault naturally as we come through apex. Nothing we need to think about. So this effect is usually neglected. Or considered part of something else. Right?

Yes it is often neglected, but IMO that is a mistake. What causes the big upwards accelerationwe see in a typical retracted release?

That is why I say that a pure OLR or ILE does not exist in high end skiing.

Quote:
Originally Posted by loki1

Just a simple truth: Fast racers try to eliminate the float between turns. The reason is simple, and if you watch and listen to what Ligety says you'll see why, skis that are floating or light do not turn! The reason Ligety has such a fast transition is so that he can pressure the ski as early as he can. Becaus the skis have such a long radius 35m and he carves more than anyone he needs to start that carve sooner and can't afford to have a lengthy float phase. That is another reason he moves his weight to the inside leg and pushes on it as he rolls from the little toe edge to the big toe edge. That move allows him to absorb some of the energy, from the turning ski, in the leg letting him maintain some pressure through the transition. This is totally in line with what Phil is saying as well. I aslo remember have essentially the same conversation with Phil while I was coaching his son. The conversation was centered on getting athletes to move thier hips forward through transition by pushing on the uphill ski, he asid it was the number one deficiency he saw in athletes coming to him. We also spoke about maintaining pressure through the transition to allow athletes to start to shape the turn as soon as possible.

I don't think anyone has argued for a long light phase. Please explain how the light phase, which obviously exist in many high-G trns including the one Ligety is talking about, would be faster if you push while the skis are flat?

Empirical studies like Reid has shown that the fastest racers have the CoM go up and down about 60 cm in a 13 m course.

Just to understand what it takes to move up and down in a short time, lets assume that a skier has an unweighted state during half the turn, and an opposite and equal magnitude upwards acceleration during the other half of the turn.

The time it takes to make this movement can then easily be calculated as

t=4 * Sqrt[0.6/9.81]   = 0.99 Sec.

So it basically takes a second, which is about the length of one SL turn.

This is of course an oversimplification, but it should be pretty clear that in order to move up and down this fast you need to be both light and heavy in the vertical direction throughout the turn.

Quote:
Originally Posted by Jamt

Empirical studies like Reid has shown that the fastest racers have the CoM go up and down about 60 cm in a 13 m course.

Just to understand what it takes to move up and down in a short time, lets assume that a skier has an unweighted state during half the turn, and an opposite and equal magnitude upwards acceleration during the other half of the turn.

The time it takes to make this movement can then easily be calculated as

t=4 * Sqrt[0.6/9.81]   = 0.99 Sec.

So it basically takes a second, which is about the length of one SL turn.

This is of course an oversimplification, but it should be pretty clear that in order to move up and down this fast you need to be both light and heavy in the vertical direction throughout the turn.

Yes, we need to be both light and heavy. When carving, most of our "heaviness" comes from generated turn forces. So flexing through the transition serves two purposes, we try to keep our up-and-down motion of our CoM below 60cm and we try to down-unweight all excessive up-force generated from a combination of turn forces and ski rebound. However, if you never carve with your hips below the distance from your knees to your ski base perpendicularly to the snow, about 60cm, you do not need to flex through the transition because "vaulting over" would provide you with that 60cm up-and-down motion already mentioned. There is one big draw back with aggressive flexing through the transition. It puts you in the back seat. So what you do is at one end you flex trough the transition OLF style when that is needed and at the other you vault over extended ILE style when that is the way to go. And a combination of both and everything in between.

Edited by tdk6 - 1/3/16 at 2:56am

Jamt - If you pushed up at transition to add "pressure" you would unweight yourself closely after. Sometimes you want to do that. If you flex through transition to add and maybe extend the "float" you weight yourself closely after. Sometimes you want to do that. No absolutes here. You guys must be talking in circles. Both transition types includes vaulting of the lower legs.

Quote:
Originally Posted by loki1

Just a simple truth: Fast racers try to eliminate the float between turns. The reason is simple, and if you watch and listen to what Ligety says you'll see why, skis that are floating or light do not turn! The reason Ligety has such a fast transition is so that he can pressure the ski as early as he can. Becaus the skis have such a long radius 35m and he carves more than anyone he needs to start that carve sooner and can't afford to have a lengthy float phase. That is another reason he moves his weight to the inside leg and pushes on it as he rolls from the little toe edge to the big toe edge. That move allows him to absorb some of the energy, from the turning ski, in the leg letting him maintain some pressure through the transition. This is totally in line with what Phil is saying as well. I aslo remember have essentially the same conversation with Phil while I was coaching his son. The conversation was centered on getting athletes to move thier hips forward through transition by pushing on the uphill ski, he asid it was the number one deficiency he saw in athletes coming to him. We also spoke about maintaining pressure through the transition to allow athletes to start to shape the turn as soon as possible.

Quote:
Originally Posted by Jamt

I don't think anyone has argued for a long light phase. Please explain how the light phase, which obviously exist in many high-G trns including the one Ligety is talking about, would be faster if you push while the skis are flat?

Maybe this is Ligety's secret...... that others do not to believe in pushing the hip forward.

Quote:
Originally Posted by Jamt

Right, but you basically said it is not used in high end racing. So what is causing the upwards acceleration?
Please explain how the ski pushes you upwards when it comes closer to the snow when untipped.

Though poorly written, what I was saying was vaulting to get weightless is not the standard of excellence for high end racing, because sometimes you want to be heavy.

Next, when the com goes up and down during the turn, there are centrifugal forces that maintain pressure on the skis.

Finally, after thinking more about vaulting, I'm not sure we're thinking of the same thing. You said one advantage of being weightless is that you come down with more pressure on the edge. The way I'm thinking of vaulting in racing to get weightless, you would have rotational momentum and horizontal momentum moving you away from your new edge which would be a bad thing. Maybe you could explain how you vault to get weightless.
I am by no means a physicist, but the com takes an arc as well based on where we WANT it to be in the future. It's falling with momentum, whether we push it there or vault there, so there must be an arc.
Quote:
Originally Posted by Tip Ripply

I am by no means a physicist, but the com takes an arc as well based on where we WANT it to be in the future. It's falling with momentum, whether we push it there or vault there, so there must be an arc.

If you are projecting your com then it is an active inertial move. If you are just letting it "fall" then it is passive. The com travels in an arc (circular path) only when the skis (against which the com is is balancing) make it so.

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