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# Why do racers lift the outside ski? - Page 5

Quote:
Originally Posted by Utahski

Arguing definitions/terminology is your thing. But you don't seem to understand that running tight slalom gates on a short pogo-stick ski isn't the same as running gs gates on a 195cm ski with 35M radius.

So here's my take on definition arguments around here.

I'll say, "I like bananas."

Then someone replies, "You are wrong, Mr. Engineer, you couldn't possibly like bananas, because they went nearly extinct before you were born.  You simply do not understand bananas.  We'll try to explain it to you, though I don't think you'll understand it, because you can't swallow bananas whole."

Then I'll reply, "It was the Gros Michel banana that got nearly wiped out.  I eat and enjoy everyday the Cavendish banana which is also considered a banana.  Most people around me call it a banana."

Then people reply, "Oh no, here we go again arguing definitions."

Quote:
Originally Posted by The Engineer

Applying rotary force to twist the skis while they are on the ground or in the air is not carving.  The reason I am pointing out that the skis are in the air is because it's indisputable that the skis are twisting because of rotary force.  If someone is making a  90 degree turn, then 25 degrees just by twisting the skis accounts for almost a third of the turn by rotary force.  In arc to arc carving all 90 degrees of the turn would result from carving.

Indisputable? Are you quite certain that the only way the skis turn in the air is by a twisting motion applied by the skier?
Quote:
Originally Posted by Pacmantwoskis

Indisputable? Are you quite certain that the only way the skis turn in the air is by a twisting motion applied by the skier?

In that example.

Quote:
Originally Posted by razie

he second is to recognize that he is very patient... throughout this entire floating phase, he is not pushing into the skis one bit and you I think acknowledged this. He is extremely patient and waiting form your first frame to the last frame, maybe 3 ski lengths, before thinking about pushing. He is eventually pushing early, just like he says, just not early as you understood it.

@Atomicman and @Pacmantwoskis - I hadn't addressed TE's pushing assertion, because this is what I had already said about pushing... I think we all agree  on this bit - he's not pushing when TE things he says he's pushing, i.e. on LTE, but after a "platform" has been developed - i.e. enough angles are built, as all modern ski instruction manuals say to do - at the end of the transition.

ps/edit yes - he is also not pushing in the sense of actively extending - but just resisting the forces that are building up because of other movements he did prior.

Also - Aman, as to LTE and weightless - that is the interesting bit here. He releases by transferring to the LTE and then immediately starts floating because of all the forces he generated in the previous turn... that's in terms of sequence of events.

If TE's and CT's understanding of technique is limited to defining this entire awesome turn as a "pivot turn" or nothing more than a "pivot entry" that's their problem, honestly - I have no need to change their opinion.

Edited by razie - 2/7/16 at 8:26pm
Quote:
Originally Posted by razie

@Atomicman and @Pacmantwoskis - I hadn't addressed TE's pushing assertion, because this is what I had already said about pushing... I think we all agree  on this bit - he's not pushing when TE things he says he's pushing, i.e. on LTE, but after a "platform" has been developed - i.e. enough angles are built, as all modern ski instruction manuals say to do - at the end of the transition.

ps/edit yes - he is also not pushing in the sense of actively extending - but just resisting the forces that are building up because of other movements he did prior.

Also - Aman, as to LTE and weightless - that is the interesting bit here. He releases by transferring to the LTE and then immediately starts floating because of all the forces he generated in the previous turn... that's in terms of sequence of events.

If TE's and CT's understanding of technique is limited to defining this entire awesome turn as a "pivot turn" or nothing more than a "pivot entry" that's their problem, honestly - I have no need to change their opinion.

You step to the new ski to put weight on it and remove weight from the other ski.  It's called a weight transfer.  The weight transfer helps tip the ski.  You don't step onto the new ski just to go in the air in the next split second.  That's pointless.  He's not stepping onto the inside ski in that video, before going into the air.  You're mixing two different transition types into one pointless, fictional sequence.

Why do you have to keep saying it's so limiting or such an insult to call it a pivot entry?  Pivots are used all over the place.  You don't have to look down on Ted for doing a pivot entry.  The only insults being made to Ted are the one's coming from you that try to diminish the value of that turn just because it's a pivot entry.  It's an excellent turn, but it's not arc to arc carving.  Arc to arc carving has no place in that turn at that speed.

Quote:
Originally Posted by The Engineer

Why do you have to keep saying it's so limiting or such an insult to call it a pivot entry?  Pivots are used all over the place.  You don't have to look down on Ted for doing a pivot entry.  The only insults being made to Ted are the one's coming from you that try to diminish the value of that turn just because it's a pivot entry.  It's an excellent turn, but it's not arc to arc carving.  Arc to arc carving has no place in that turn at that speed.

Are you saying that Ted's skis turn in the air because he is twisting or rotating his legs while airborne?
Quote:
Originally Posted by The Engineer

Why do you have to keep saying it's so limiting or such an insult to call it a pivot entry?  Pivots are used all over the place.  You don't have to look down on Ted for doing a pivot entry.  The only insults being made to Ted are the one's coming from you that try to diminish the value of that turn just because it's a pivot entry.  It's an excellent turn, but it's not arc to arc carving.  Arc to arc carving has no place in that turn at that speed.

Just to note that you continue to call this turn below a pivot turn or a pivot entry...  not only that, but you reduce the value of the entire clip as just showing us a pivot entry... skipping over many technical elements.

I am seriously flabbergasted... that anyone can find any pivot of any kind in the turn above, right there, at that speed: the new outside ski simply does not pivot even one inch...

and for clarification of whatever definition of pivoting you may be using: when we put the ski on edge and it carves its way around the turn, we don't call that pivoting...

Just to also note that you're saying that Ted cannot (or should not?) arc to arc a basic GS turn (that turn, at that speed)... when we're just looking at one. This does not qualify for deserving a reply - just emphasizing and framing for posterity.

Edited by razie - 2/7/16 at 9:40pm
Quote:
Originally Posted by razie

Just to note that you continue to call this turn below a pivot turn or a pivot entry...  not only that, but you reduce the value of the entire clip as just showing us a pivot entry... skipping over many technical elements.

I am seriously flabbergasted... that anyone can find any pivot of any kind in the turn above, right there, at that speed: the new outside ski simply does not pivot even one inch...

and for clarification of whatever definition of pivoting you may be using: when we put the ski on edge and it carves its way around the turn, we don't call that pivoting...

Just to also note that you're saying that Ted cannot (or should not?) arc to arc a basic GS turn (that turn, at that speed)... when we're just looking at one. This does not qualify for deserving a reply - just emphasizing and framing for posterity.

I watched this clip running it up and back 10 times...definite subtle and small pivot move. . No doubt about this is not a purely carved arc to arc turn.  Yes he slightly rotates the skis. It is not a big redirection ro big drift, but there is a definetly a subtle pivot element to it!

Quote:
Originally Posted by Atomicman

I watched this clip running it up and back 10 times...definite subtle and small pivot move. . No doubt about this is not a purely carved arc to arc turn.  Yes he slightly rotates the skis. It is not a big redirection ro big drift, but there is a definetly a subtle pivot element to it!

I do see some on the inside ski, as it's tipped into the turn, but not on the outside... all I see on the outside ski is rolling on edge, while it maintains the same direction... and it only changes direction while on edge... it feels like there could be a pivot, because he's floating for so long - but it is amazing the kind of control he has - to again float for a couple ski lengths without unwinding and pivoting the skis.

Still - would that define this turn? Would you seriously call this a "pivot entry" though? As opposed to arc to arc?

Let's assume the outside ski changes direction one inch, during a distance of three ski lengths - does that qualify as a pivot for you? How much would it change direction had it been on sidecut? Can anyone seriously call that a pivot? And define that turn as a "pivot entry" ?

Quote:
Originally Posted by The Engineer

“what you want to be looking for is as close to a full arc or pressure starting as soon as possible, another way to look at it, has the ski turned before it really bites and bends.”  What you need to be doing as you start to roll this knee in and drive your hip forward, in this part of the turn in the top part of the turn you’re going to need to get a little more push and pressure so the ski carves a little bit more there.”  “If you let yourself get too light you can’t get heavy again on this foot quick enough to bend it at the top of the turn.”

Thanks for clearing that up. Now it is obvious that by pushing he does not mean extending, since the leg was already completely extended.

It is also clear that by too light he means too high/too extended.

Like one of the previous clips, this is coaching of a beginner. It has very little to do with Ted's transition.

Things are getting pretty hopeless here.  I've proven that there is at least 25 degrees of rotation of the ski not from carving which could be 1/3 of the turn for that second slow motion clip of Ted.  You can look at that video by Phil and see what it means to arc to arc carve.  You can see the fundamentals necessary to arc to arc carve that Phil first prioritizes before working on pivot entries; he said exactly that in the first video we were talking about in the other thread.  Yes, arc to arc carving seems to be the foundation to learn for beginners in the ski racing progression, and it's an essential and difficult transition to master.  Whenever you want to arc to arc carve you've got to be heavy for all the reasons laid out by Phil in that video.  Maybe you'll do it perfectly 2-3 turns is a run in some courses as described by Ted, but that might just make the difference.  In some conditions it will be more often.  Some of you didn't even know the difference between arc to arc carving and pivoting, so that's a long hill to climb to understand what's happening in transition when knowledgeable people like Loki try to explain it.

Here are some uses of the word pivot, since people seem to have some unnecessary constraints for that word:

http://www.yourskicoach.com/glossary/SkiGlossary/Pivoting.html

http://my.ussa.org/alpine-programs/athletes/development/skillsquest/skiing-assessment/exercises-by-skill/rotary/hop-turns

Quote:
Originally Posted by razie

Quote:
Originally Posted by Atomicman

I watched this clip running it up and back 10 times...definite subtle and small pivot move. . No doubt about this is not a purely carved arc to arc turn.  Yes he slightly rotates the skis. It is not a big redirection ro big drift, but there is a definetly a subtle pivot element to it!

I do see some on the inside ski, as it's tipped into the turn, but not on the outside... all I see on the outside ski is rolling on edge, while it maintains the same direction... and it only changes direction while on edge... it feels like there could be a pivot, because he's floating for so long - but it is amazing the kind of control he has - to again float for a couple ski lengths without unwinding and pivoting the skis.

Still - would that define this turn? Would you seriously call this a "pivot entry" though? As opposed to arc to arc?

Let's assume the outside ski changes direction one inch, during a distance of three ski lengths - does that qualify as a pivot for you? How much would it change direction had it been on sidecut? Can anyone seriously call that a pivot? And define that turn as a "pivot entry" ?

A-man... let me explain some of the biomechanics that TE is missing when declaring that a pivot - when she (or Rick) declares a pivot to be the slight redirection of the skis that occurs because of biomechanical interactions not related to rotary but to tipping, she may as well declare carving a pivot and completely strip the word of semantics.

There's a very simple thing you can do in the living room: keep the foot flat in the air and tibia vertical. now tip the knee/foot at 45 degrees while still in the air - the foot did not change direction. Now close the ankle and repeat. you will notice the foot changed direction, because the ankle is closed (the heel will obviously point slightly outwards).

When this is done in the air or only with the tip slightly supported, a slight redirection of the skis occurs. When the entire edge is supported by the snow, the knee redirects instead, to maintain alignment. That's all there is to it - this is why it may look like a pivot but there actually isn't one. This redirection is a result of tipping the skis on edge while in the air and is completely immaterial to the turn development.

A pivot entry is characterized by a skidding of the skis when flat and slightly on edge, due to a rotary effort, to get a different line, followed by an edge set and that simply does not happen here. The ski does not skid while on edge, just subtly switches from one set of edges to the other, after floating for a while, with a hint of redirection because of tipping in the air. Hence we call this arc to arc and marvel at the awesomeness of Ted's ability to keep everything together while floating patiently for so long.

Edited by razie - 2/8/16 at 5:37am

Now that we're past this weird "Ted's just pivoting" episode, due to some poster's lack of understanding of basic rotary and edging biomechanics, we can go back to the subject:

Did someone relate this to tipping yet?

Edited by razie - 2/8/16 at 6:14am
Quote:
Originally Posted by razie

A-man... let me explain some of the biomechanics that TE is missing when declaring that a pivot - when she (or Rick) declares a pivot to be the slight redirection of the skis that occurs because of biomechanical interactions not related to rotary but to tipping, she may as well declare carving a pivot and completely strip the word of semantics.

There's a very simple thing you can do in the living room: keep the foot flat in the air and tibia vertical. now tip the knee/foot at 45 degrees while still in the air - the foot did not change direction. Now close the ankle and repeat. you will notice the foot changed direction, because the ankle is closed (the heel will obviously point slightly outwards).

When this is done in the air or only with the tip slightly supported, a slight redirection of the skis occurs. When the entire edge is supported by the snow, the knee redirects instead, to maintain alignment. That's all there is to it - this is why it may look like a pivot but there actually isn't one. This redirection is a result of tipping the skis on edge while in the air and is completely immaterial to the turn development.

A pivot entry is characterized by a skidding of the skis when flat and slightly on edge, due to a rotary effort, to get a different line, followed by an edge set and that simply does not happen here. The ski does not skid while on edge, just subtly switches from one set of edges to the other, after floating for a while, with a hint of redirection because of tipping in the air. Hence we call this arc to arc and marvel at the awesomeness of Ted's ability to keep everything together while floating patiently for so long.

25 degrees of rotation in the air is not a "hint of redirection". Lol. Your biomechanical nonsense is completely irrelevant. It doesn't matter why the skis are rotating 25 degrees in the air, because no matter what the reason, rotating in the air is not carving.
Quote:
Originally Posted by The Engineer

Your biomechanical nonsense is completely irrelevant. It doesn't matter why the skis are rotating 25 degrees in the air, because no matter what the reason, rotating in the air is not carving.

The only irrelevant thing here is your measure of pivot. What is relevant is if there is redirection or not.

By the way folks, in that New York Times Ligety video there are two slow motion clips of the same turn, but it's not from the same run.  I chose the second run, because it's more obvious and simple what's happening.  The first one has more rotation of the inside ski and loading of that inside ski when he lands, but less outside ski rotation.  It gets complicated to analyze, because it's hard to say how much weight he has on each leg when he lands, and therefore the role of the inside leg that was rotated quite a bit.  The second one is very clear, because both skis rotate quite a bit in the air.  It's indisputable in the second clip that it's not arc to arc carving.  I don't believe the first clip is arc to arc carving either, but it's hard to say exactly what's happening beyond any reasonable doubt like you can in the second one.

Edited by The Engineer - 2/8/16 at 7:28am
Quote:
Originally Posted by The Engineer

By the way folks, in that New York Times Ligety video there are two slow motion clips of the same turn, but it's not from the same run.  I chose the second run, because it's more obvious and simple what's happening.  The first one has more rotation of the inside ski and loading of that inside ski when he lands, but less outside ski rotation.  It gets complicated to analyze, because it's hard to say how much weight he has on each leg when he lands and therefore the roll of the inside leg that was rotated quite a bit.  The second one is very clear, because both skis rotate quite a bit in the air.  It's indisputable in the second clip that it's not arc to arc carving.  I don't believe the first clip is arc to arc carving either, but it's hard to say exactly what's happening beyond any reasonable doubt like you can in the second one.

What causes the skis rotate in the air?

Earlier you said that
Quote:
it's indisputable that the skis are twisting because of rotary force
ie. A pivot

But now it seems that you have backed away from saying he is pivoting to saying that it's not arc to arc carving. Which is it?
Quote:
Originally Posted by Pacmantwoskis

What causes the skis rotate in the air?

Earlier you said that
ie. A pivot

But now it seems that you have backed away from saying he is pivoting to saying that it's not arc to arc carving. Which is it?

Like I said earlier, I don't want to argue definitions all day long.  Also, I don't want to try to explain through engineering exactly why such and such must happen.  Both types of arguments will be tedious and go nowhere.  It's clear to most people not desperate to be right in an argument that rotating the skis in the air is not arc to arc carving.  It doesn't matter why the skis are rotating in the air, because you can not carve in the air.  There's nothing to bend the ski, so carving is not the reason the ski is rotating.  Many people call rotating the ski like this a pivot.  I tried to avoid using this word, because it was becoming clear that this word was going to be used to obscure things by arguing the definition, so it's simpler just to call it rotation in the air.  The point is that this is not an arc to arc carve turn, so it should not be used as an example transition for arc to arc carving.  It's an example transition for a pivot entry.

Quote:
Originally Posted by Pacmantwoskis

But now it seems that you have backed away from saying he is pivoting to saying that it's not arc to arc carving. Which is it?

well, she started by explaining how that is a pivot turn several times, then pivot entry, then emphatically declaring that arc to arc doesn't even belong in that turn... which is a basic GS turn...

Arc to arc simply means just that: you carve an arc and then carve another arc. If the skis redirected slightly in-between, while in the air because they are tipped on edge, without any skidding, it simply does not change the arc-to-arc nature of those turns...

Quote:
Originally Posted by razie

well, she started by explaining how that is a pivot turn several times, then pivot entry, then emphatically declaring that arc to arc doesn't even belong in that turn... which is a basic GS turn...

Arc to arc simply means just that: you carve an arc and then carve another arc. If the skis redirected slightly in-between, while in the air because they are tipped on edge, without any skidding, it simply does not change the arc-to-arc nature of those turns...

Arc to arc carving means that whenever the skis are turning, it's from carving.  This goal of carving the entire turn is explained very nicely in that video by Phil that I posted.  Pivots have great uses for many basic GS turns, sometimes arc to arc carving does as well.  It's your mistake to assume that one turn type captures the entire essence of GS skiing.  I think this explains why you were having so much trouble understanding Phil's videos, Loki's explanations, the USSA documents, and Rick's material.  You had no idea what it even means to arc to arc carve, so how can you possibly disseminate information specific to that type of turn. You have been arguing with such truth that weightless transitions are fabulous for pivoting.  I have to agree with you there as I've agreed before.

http://www.yourskicoach.com/glossary/SkiGlossary/Arc_to_Arc.html

Edited by The Engineer - 2/8/16 at 8:20am

oh - interesting, another Rick definition - for arc to arc this time...

Quote:
This is linking carved turns together with absolutely no pivoting, pushing, steering or twisting of the skis downhill during the transition between turns.  To end one turn and begin the next, the skis are simply tipped off their uphill edges, then onto their downhill edges.  When done properly, two cleanly carved sets of tracks are left behind, joined together by a moment when the skis were flat on the snow.

This is exactly what Ted does: he does not pivot, push, steer or twist the skis. He just tipped them. and we only see two sets of tracks (of course the outside ski is the one that matters though, for racers).

I'm not even clear where this is going... can you relate it back somehow to why racers lift the outside ski between turns?

Noting that your definitions and naming of things keep changing, declaring biomechanics irrelevant - are you certified in some ski coaching/instructing system at all?

... are there any other definitions you're aware of other than Rick's website (lots of info there) - which you keep placing links to here?

Edited by razie - 2/8/16 at 8:10am
Quote:
Originally Posted by razie

oh - interesting, another Rick definition - for arc to arc this time...

This is exactly what Ted does: he does not pivot, push, steer or twist the skis. He just tipped them. and we only see two sets of tracks (of course the outside ski is the one that matters though, for racers).

I'm not even clear where this is going... can you relate it back somehow to why racers lift the outside ski between turns?

It's not just Rick's definition.  You can see Phil emphasizing how to carve the top of the turn in that video.  Ted is not carving the top of the turn without a doubt shown by the 25 degrees of rotation of the skis in the air, which is either a pivot, push, steer, or twist.  It doesn't matter which one it is, but it's certainly one of them, maybe all of them.  I've already described where this is going.  It's showing that you have no idea what you are talking about, and posting that turn transition from Ted is merely showing a beautiful pivot entry.  So long Razie, it's been fun.  There's no point in arguing more, because I know the next post from you:  "Define skiing. Can we really say that he's skiing at that moment, so do any of these other definitions really apply?"

Edit:  Looking below, I got that wrong.  I should have said his next post would be: "Define the top of the turn.  Can we really say he's not carving the top of the turn?"

Edited by The Engineer - 2/8/16 at 8:29am
Quote:
Originally Posted by The Engineer

Ted is not carving the top of the turn without a doubt shown by the 25 degrees of rotation of the skis in the air, which is either a pivot, push, steer, or twist.  It doesn't matter which one it is, but it's certainly one of them, maybe all of them.

You've got to be kidding me... well, us, I mean the world - because this is a public forum...

You say Ted does not carve the top of that turn? You don't know what he does from that list, but surely it is one of those ??? Maybe all, for good measure ????

So when he's pushing early while upside down... he's carving what... the bottom?

I mean you drew the lines there showing the direction of the ski while at the same time you also said it "landed" and is carving... do you think that's the bottom of the turn ????

Edited by razie - 2/8/16 at 8:59am
Quote:
Originally Posted by The Engineer

Ted is not carving the top of the turn without a doubt shown by the 25 degrees of rotation of the skis in the air, which is either a pivot, push, steer, or twist. It doesn't matter which one it is, but it's certainly one of them, maybe all of them.  I've already described where this is going.  It's showing that you have no idea what you are talking about, and posting that turn transition from Ted is merely showing a beautiful pivot entry.  So long Razie, it's been fun.  There's no point in arguing more, because I know the next post from you:  "Define skiing. Can we really say that he's skiing at that moment, so do any of these other definitions really apply?"

How can you claim this with such certainty? Is it possible that you are missing something that would create the rotation in the air that would not require rotary input, twisting, or pivoting by Ligety? I have never felt the forces at play during a WC GS transition (presumably you haven't either), but I do have experience with slalom transitions (obviously not WC). There is so much energy(pop) available, that I never need to rotate or pivot the skis. They come around rather quickly of their own accord, and I generally need to hold them back from coming around too much. An anti-pivot, one might say.
Quote:
Originally Posted by Pacmantwoskis

How can you claim this with such certainty? Is it possible that you are missing something that would create the rotation in the air that would not require rotary input, twisting, or pivoting by Ligety? I have never felt the forces at play during a WC GS transition (presumably you haven't either), but I do have experience with slalom transitions (obviously not WC). There is so much energy(pop) available, that I never need to rotate or pivot the skis. They come around rather quickly of their own accord, and I generally need to hold them back from coming around too much. An anti-pivot, one might say.

First of all I don't really care, because rotating in the air is not carving, and that's the only important point to the conversation, but since you keep insisting:

Newton's first law of physics:

I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it

In the air, there is nothing external to the body to change the direction of the skis, but yet the direction changes.  So, either the skis were rotated by the skier with a torque, or the skis already had angular momentum before leaving the ground.  So, how can the skis get angular momentum before leaving the ground?

Does he have angular momentum generated from turning?  Well he's leaving the ground in transition, so he hasn't built up any angular momentum in the next turn yet.  Could he be bringing angular momentum from the previous turn?  Sure, but the spin is going in the opposite direction.  Spin direction is critically important for conservation of angular momentum.

I've stumbled across some of these debates where one group says there should be no rotary, but yet rotary is visible, so there's all these explanations about how rotary can be just a passive natural byproduct of carving.  BUT, you are misusing those arguments right or wrong for this situation of when the skis are in the air.  In the air, there is no passive pivoting due to for aft pressure or any other type of phenomenon.  There can be no passive changes in direction of the skis in the air, and there is clearly no initial angular momentum in the proper direction.  He would really have to be well into the turn before he goes into the air to get that much rotation just from his existing angular momentum, therefore he's twisting his skis in the air.

I've also seen on certain web sites how pivoting the skis like this is called low level skiing, so I see this as a bitter pill for you to swallow.  But it's just not true.  Great skiers pivot when necessary.  Low level skiers are the one's that can't carve the top of the turn when necessary.  So, let's not rehash that argument and say whether Ted made a mistake or not, but it's clear in that turn that the skis rotate in the air.  It can only come from the skier in this example.  It's not carving the top of the turn, so let's not use this video as an example transition for arc to arc carving.

Edited by The Engineer - 2/8/16 at 10:00am

This is beyond physics or biomechanics or ski technique... why don't you start a "Ted's pivots" thread and move these notions there? I promise to stay out of that...

Quote:
Originally Posted by The Engineer

In the air, there is nothing to change the direction of the skis, but yet the direction changes.

There can be no passive changes in direction of the skis in the air,

It's not carving the top of the turn, so let's not use this video as an example transition for arc to arc carving.

Just collecting quotes at this point...

Quote:
Originally Posted by razie

This is beyond physics or biomechanics or ski technique... why don't you start a "Ted's pivots" thread and move these notions there? I promise to stay out of that...

Originally Posted by The Engineer

In the air, there is nothing to change the direction of the skis, but yet the direction changes.

There can be no passive changes in direction of the skis in the air,

It's not carving the top of the turn, so let's not use this video as an example transition for arc to arc carving.

Just collecting quotes at this point...

Fixed the top one, thanks, but the others look ok.

Quote:
Originally Posted by The Engineer

First of all I don't really care, because rotating in the air is not carving, and that's the only important point to the conversation, but since you keep insisting:

Newton's first law of physics:

I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it

In the air, there is nothing external to the body to change the direction of the skis, but yet the direction changes.  So, either the skis were rotated by the skier with a torque, or the skis already had angular momentum before leaving the ground.  So, how can the skis get angular momentum before leaving the ground?

Does he have angular momentum generated from turning?  Well he's leaving the ground in transition, so he hasn't built up any angular momentum in the next turn yet.  Could he be bringing angular momentum from the previous turn?  Sure, but the spin is going in the opposite direction.  Spin direction is critically important for conservation of angular momentum.

I've stumbled across some of these debates where one group says there should be no rotary, but yet rotary is visible, so there's all these explanations about how rotary can be just a passive natural byproduct of carving.  BUT, you are misusing those arguments right or wrong for this situation of when the skis are in the air.  In the air, there is no passive pivoting due to for aft pressure or any other type of phenomenon.  There can be no passive changes in direction of the skis in the air, and there is clearly no initial angular momentum in the proper direction.  He would really have to be well into the turn before he goes into the air to get that much rotation just from his existing angular momentum, therefore he's twisting his skis in the air.

I've also seen on certain web sites how pivoting the skis like this is called low level skiing, so I see this as a bitter pill for you to swallow.  But it's just not true.  Great skiers pivot when necessary.  Low level skiers are the one's that can't carve the top of the turn when necessary.  So, let's not rehash that argument and say whether Ted made a mistake or not, but it's clear in that turn that the skis rotate in the air.  It can only come from the skier in this example.  It's not carving the top of the turn, so let's not use this video as an example transition for arc to arc carving.

It's too bad that you don't care how carving (and properly timed releases) or lack thereof relates to what happens in the air. This is quite telling of how you are attempting to analyze what's happening without accounting for everything that is occuring that affects what happens in the air.

I am happy to agree that it is not arc to arc, if you say that arc to arc skiing requires that there is no separation between skis and snow. Fine with me. Not arc to arc.

Regarding pivoting/twisting:
You are welcome to use rotary and pivoting in the gates or while freeskiing all you like. That won't bother me one bit. Ignorance is bliss, but until you've felt how unnecessary pivoting/twisting is (except in the cases of compensating for an error, coming to a rapid stop, doing it because you enjoy the sensation, dealing with a fox that has suddenly darted in front of you, etc.) and until you've released a bent ski and dealt with the forces at transition that require you to actively prevent the rotation of the skis, then you have no argument. When trying to theoretically account for all forces at play, it is far too easy to inadvertently miss one condition that substantially alters the outcome. If you had ever felt an anti-pivot, the need to active prevent the skis from rotating due to the release at transition, then as an engineer, you'd probably be curious as to why that happens. You've clearly never felt it. Come back when you do because I am very interested in hearing from an engineer more about the forces at play.

The rotation that occurs in the air was not initiated in the air. The resulting (non-active) rotation is a result of things that occur before being airborne. I'm simply a skier, I'm happy to relate what movements I am making and not making. Are you telling me that when I say that I prevent or hold back the rotation that occurs coming out of a transition that I am simply lying to you? You're the engineer with the capacity to dig deeper to find out what's really happening. There is more to the transition than you are seeing and accounting for.
Quote:

Originally Posted by The Engineer

In the air, there is nothing external to the body to change the direction of the skis, but yet the direction changes.  So, either the skis were rotated by the skier with a torque, or the skis already had angular momentum before leaving the ground.  So, how can the skis get angular momentum before leaving the ground?

Like I said - no torque to the skis needed to reposition the skis... it's just the biomechanics of edging, as I explained already... our body's segments re-arranging due to simple movements of the turn like edging - which have nothing to do with applying torque to or twisting the skis... it is simply not the same as rotary, but a different category.

Quote:
Originally Posted by razie

A-man... let me explain some of the biomechanics that TE is missing when declaring that a pivot - when she (or Rick) declares a pivot to be the slight redirection of the skis that occurs because of biomechanical interactions not related to rotary but to tipping, she may as well declare carving a pivot and completely strip the word of semantics.

There's a very simple thing you can do in the living room: keep the foot flat in the air and tibia vertical. now tip the knee/foot at 45 degrees while still in the air - the foot did not change direction. Now close the ankle and repeat. you will notice the foot changed direction, because the ankle is closed (the heel will obviously point slightly outwards).

When this is done in the air or only with the tip slightly supported, a slight redirection of the skis occurs. When the entire edge is supported by the snow, the knee redirects instead, to maintain alignment. That's all there is to it - this is why it may look like a pivot but there actually isn't one. This redirection is a result of tipping the skis on edge while in the air and is completely immaterial to the turn development.

Again, to clarify: when a tipping ski is on snow, the knee moves in. When the tipping ski is not on snow, both the knees move in and the ski moves out and a closed ankle simply causes the heel to move out more than the toes, re-orienting the ski slightly.

...those pesky biomechanics which are irrelevant in your opinion, are what allows us to ski... prisoners to geometry and physics as we are!

Look. Seriously: please get a separate thread for this "Ted is pivoting" dissertation... you've managed to throw off this good discussion a lot as it is...

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