lateral weight shift vs rocking the ski fore-aft

[James]

Well, a patience transition, like a patience turn, could help. I suppose. Outside ski to outside ski or yo and over, whatever you call it.

My objection was "this is the way to ski, this is how we actually should ski, everything was wrong, this new way is based on physics". Total crock. Perhaps I over interpreted. But, based on words in that segment, not really.

This is my prob with all these groups, not limited to NZ. There's always a flavor of the year and some of these guys come back from trainings and see whatever that was everywhere.

↑
I see people pushing it to get it down now.
@James get what down now? Just for clarification on my part...

Well that was poorly written. What I meant was pushing the skis out to get the com downhill, inside, now-right away.
But, more accurately, probably just pushing to turn. There's a problem in general with balancing on the outside ski. Then we get pitch involved and they don't really want to go downhill, so push the outside ski. Twice often, the old and the new. These things aee ingrained.

Haha, then we could discuss actually using the inside ski. A la Richie Berger, etc.

 

[Mike King]

My objection was "this is the way to ski, this is how we actually should ski, everything was wrong, this new way is based on physics". Total crock. Perhaps I over interpreted. But, based on words in that segment, not really.

This is my prob with all these groups, not limited to NZ. There's always a flavor of the year and some of these guys come back from trainings and see whatever that was everywhere.

I'm relatively new to ski instruction, but my understanding is that this stuff goes around and around. This year it is x, next y, etc. than in a few years, it's x again.

Mike

 

[geepers]

That is certainly the distinction between interpolate and extrapolate for a mathematical function. Whether it carries over into general English usage (where it is, after all, a metaphor) is an open question.

@James was having a dig at the NZ instructor physics so I thought I'd go a little didactic.

I guess, the question is, would extrapolate be used for a quantum situation, as everything is a probability?
I'm way off the bell curve of my knowledge now.

Let's go with @mdf on this one. He's a sifu on this i/e topic. (And let's stay completely away from quantum physics for skiing.)

One way to look at unbalance is to imagine what would happen if all motion was instantaneously stopped so that dynamic forces are not in play.
In a static unbalance situation, you would fall over.
Dynamic unbalance is more complicated but the concept is the same.
There is a moment in time where you are not in static balance and if some dynamic forces don't kick in soon you are going to fall over.
The reason you need to do unbalanced stuff is so you are in the right place when the ski starts to turn under you.
We all experience that "moment of doubt" when you do all the stuff required to initiate a turn but the ski has not started to respond yet.
That is when you move to accept the forces that are soon coming, the forces that will bring you back in balance.
Ski in the future.

If all forward motion was instantly stopped on your avatar you'd rotate vertically to the left over your inside leg. Luckily it hasn't instantly stopped yet.

Here's the thing. The outside ski won't come round if it isn't tilted and engaged in the snow and has just enough pressure on it to bend. (We could pivot the skis to bring them back but that's not a pure carving turn.) At the top of the turn there's not a lot of direction change and not a lot of force required or available. The amount that anyone can project themselves inside the turn whilst their skis take the long way around is constrained by how well they can:
1. Make edge and platform angle
2. Extend the outside leg to allow the ski to maintain contact with the snow
This is fine for racers and other highly experienced carvers who know just what to do and have the ability to recover/manage the forces.

For less experienced folk? It's like trying to do the infinity move from a standing start.

There's an age where learning to take such risks is not a big deal. Plus the strength and flexibility to deal with the forces that come back.

Yep.

On the other hand we have people apparently moving in too quickly. So, what to do?

1. Extend transition.
2. Inside out turns (strangely enough)

what are the effects, symptoms of said people. You detailed them, but it's really sort of general. What are these skiers looking to improve on? What is really the deficiency overall?

Think I answered this above. Lemmeno.

 

[markojp]

Well, I'd say I see an awful lot of Level 3 instructors who do so as well.

Yes, that's true.

 

[geepers]

Well, a patience transition, like a patience turn, could help. I suppose. Outside ski to outside ski or yo and over, whatever you call it.

My objection was "this is the way to ski, this is how we actually should ski, everything was wrong, this new way is based on physics". Total crock. Perhaps I over interpreted. But, based on words in that segment, not really.

This is my prob with all these groups, not limited to NZ. There's always a flavor of the year and some of these guys come back from trainings and see whatever that was everywhere.

In instructing context is everything. At some point in the vid he talks about students as being ski instructors. We're getting a few minutes out of what is a longer presentation and so don't know too much about the situation on snow, what subset of their material they elected to cover, etc.

I'm inclined to give them all the benefit of the doubt and just take from it what seems to fit into my own understanding. (I reserve the right to completely change my views when presented with fresh information or new insights.)

 

[Dakine]

Another example of unbalance in anticipation of new forces is jibing a windsurfer.
When you start carving the turn and set the rail you lean inside to counteract the centripetal force from the turn.
Just when you get that going you now have to let go and flip the sail.
At this point, if you don't catch the sail on the other side and rebalance, you are going in.
Very few people learn to make a smooth carved jibe because they freeze during the flip and don't catch the sail so they can rebalance.
In both sports there is a need to move to an unbalanced state so you can regain balance in the proper position to deal with the resultant forces.
I call this "the moment of impending doom" which is hopefully followed by the "force of righteousness."
A lot of people are stuck in a sport because they cannot convince themselves to experience unbalance.
To best experience this phenomena I suggest you take a pair of GS skis and put a 2 degree base bevel run a full centimeter into the base on them.
They will be faster than hell, really squirrely and give you a long time to think you are doomed before they hook up.

 

[James]

I'm relatively new to ski instruction, but my understanding is that this stuff goes around and around. This year it is x, next y, etc. than in a few years, it's x again.
Mike

Yes. I think it may be better than around 2000. At least in the East. But maybe not. The internet has opened up all sorts of stuff. At least you can see stuff. It's also opened up cults.

If you get the Sybervision video, you'll see really good skiing from the early 90's. Jens Husted, Chris Ryman. Straight skis, but very modern technique. It really hasn't changed all that much. Not sure anyone is really that much better than those guys and I haven't seen that vid in years. Hah, maybe I'm wrong.

The huge change though from say a long time ago, is the lack of racing background. Even on a casual level. The idea that McGlashan or Harb's turns have anything to do with racing is ludicrous. Slow, slow, slow. Pretty, but slow. Yet they pontificate to the nth degree on racing and never get called on it. One claims it's all based on racing. "You don't understand" . Ok, let's see one follower who can really send it between the sticks.

 

[geepers]

I call this "the moment of impending doom" which is hopefully followed by the "force of righteousness."

Do they teach that jibe move 1st day out?

 

[James]

In instructing context is everything. At some point in the vid he talks about students as being ski instructors. We're getting a few minutes out of what is a longer presentation and so don't know too much about the situation on snow, what subset of their material they elected to cover, etc.

I'm inclined to give them all the benefit of the doubt and just take from it what seems to fit into my own understanding. (I reserve the right to completely change my views when presented with fresh information or new insights.)

Yes, I mentioned the clients/instructors/students. Didn't quote it. Those are their clients- instructors mainly and some private. At least in the US. It's at like 6:25 I think.
Benefit of the doubt, sure. But why do we have to go through this in the first place? They really should release something we're dupposrd to see instead of seemingly random cell phone video. When I say "they" I mean teams.
But, we're dealing with an industry and clientele - instructors, students, who accept manufacturers telling us there's titanium in their skis when it's aluminum. Maybe this why "physics" is always mentioned. Who cares, who knows anything about it, who calls anyone on it.

 

[geepers]

Yes, I mentioned the clients/instructors/students. Didn't quote it. Those are their clients- instructors mainly and some private. At least in the US. It's at like 6:25 I think.
Benefit of the doubt, sure. But why do we have to go through this in the first place? They really should release something we're dupposrd to see instead of seemingly random cell phone video. When I say "they" I mean teams.
But, we're dealing with an industry and clientele - instructors, students, who accept manufacturers telling us there's titanium in their skis when it's aluminum. Maybe this why "physics" is always mentioned. Who cares, who knows anything about it, who calls anyone on it.

Just found this which adds a little more context to the discussion. ?Taken - on a cell phone no doubt - by the Swedes. It's set to play where the NZ guy was drawing lines in the snow - may be worth watching some other earlier bits - be nice to know what the Swedes are saying about it...

Well, hopefully each nation will put out a full vid of their on various presentations for the mere mortals who don't get to attend these things.



Titanium. It's just gross to work with. As Lockheed found building the SR71. (Maybe Blizzard should have called them Blackbirds rather than Firebirds.)

What exactly is Titanal?

The short answer is Titanal is a metal that is about 85% aluminum with smaller amounts of zinc, magnesium, and copper. Despite the deceiving name, titanium is not among the list of periodic ingredients. Titanal is produced by a single company called AMAG or Austria Metall AG. It should come at no surprise the Austrians are behind this. Austrian and German companies like Volkl, Fisher, and Blizzard are known for producing some of the stiffest and most powerful skis in the world. This is especially true in the world of racing.

“AMAG’s high-strength TITANAL and special alloys stand for unique properties that are ideally suited to the needs of the sports industry. In particular, the unsurpassed combination of best formability, anodizing and gluing excels in high-grade products such as sprockets, skis, hiking and ski poles as well as various mountaineering articles that must reliably withstand the strongest loads.” – AMAG​

While few of us are metallurgists, the main takeaway is that Titanal is mostly aluminum and possesses a set of properties that make it perfect for use in a ski. It has isotropic properties meaning it retains its strength as it is torqued in any direction. This important as skis twist and bend in many directions during a single day at the hill. In addition, it retains its strength after ski manufacturers re-heat it when setting it in their skis. Titanal is an agreeable metal as it bonds well with other materials in the layup.

There you have it. Next time the fellow at the ski shop drops the name of this marvelous metal, you will be armed with knowledge.​

 

[James]

Just found this which adds a little more context to the discussion. ?Taken - on a cell phone no doubt - by the Swedes. It's set to play where the NZ guy was drawing lines in the snow - may be worth watching some other earlier bits - be nice to know what the Swedes are saying about it...

Well, hopefully each nation will put out a full vid of their on various presentations for the mere mortals who don't get to attend these things.



Titanium. It's just gross to work with. As Lockheed found building the SR71. (Maybe Blizzard should have called them Blackbirds rather than Firebirds.)

What exactly is Titanal?

The short answer is Titanal is a metal that is about 85% aluminum with smaller amounts of zinc, magnesium, and copper. Despite the deceiving name, titanium is not among the list of periodic ingredients. Titanal is produced by a single company called AMAG or Austria Metall AG. It should come at no surprise the Austrians are behind this. Austrian and German companies like Volkl, Fisher, and Blizzard are known for producing some of the stiffest and most powerful skis in the world. This is especially true in the world of racing.

“AMAG’s high-strength TITANAL and special alloys stand for unique properties that are ideally suited to the needs of the sports industry. In particular, the unsurpassed combination of best formability, anodizing and gluing excels in high-grade products such as sprockets, skis, hiking and ski poles as well as various mountaineering articles that must reliably withstand the strongest loads.” – AMAG​

While few of us are metallurgists, the main takeaway is that Titanal is mostly aluminum and possesses a set of properties that make it perfect for use in a ski. It has isotropic properties meaning it retains its strength as it is torqued in any direction. This important as skis twist and bend in many directions during a single day at the hill. In addition, it retains its strength after ski manufacturers re-heat it when setting it in their skis. Titanal is an agreeable metal as it bonds well with other materials in the layup.

There you have it. Next time the fellow at the ski shop drops the name of this marvelous metal, you will be armed with knowledge.​

I actually have the pdf from AMAG on Titanal on the phone so I can end silly arguments. It's amazing how few in shops know. The sort of problem with the compostion list on their pdf is it doesn't include aluminum. Since it's an aluminum alloy, it assumes you already know that - like by reading the intro. We digress.

Dude, that Swedish vid makes the NZ guy even worse. This is another presentation? It's slightly different. I didn't make it more than 30 sec from your start point as he babbled even more this time about the laws of physics after the French curves. It's embarrassing. You don't "need" to create a new platform to get inside. You had one in the last turn. And you've got gravity and momentum.

The whole idea that getting inside can't happen unless you wait and push after transition, or in transition, is absurd. I can do this for one turn literally with my eyes closed. Almost anyone can. Apparently the laws of physics didn't apply before transition. Sad!

I tell you, when ski instructors reference physics, it's often the whistle before the train wreck. This is a good example.
Presentations really need to be vetted before presenting. This is what "Conferences" usually do. Then you have approved materials ready to go that can be distributed. This would've been sent back for rewording and correction of concept. Which is fine. Present the idea without the completely factually wrong reason. But then, maybe it doesn't make as much sense to present it.

 

[Dakine]

" I tell you, when ski instructors reference physics, it's often the whistle before the train wreck. This is a good example."
To my knowledge, there is only one published paper where a skier was fully instrumented and the data taken was used to reconcile a mathematical model of the physics.
That paper is very complex.
I can't say I understand the physics of skiing but I do understand enough to say much of what I read isn't theoretically sound.
You go, James!

https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/98251/eth-28070-02.pdf

 

[geepers]

" I tell you, when ski instructors reference physics, it's often the whistle before the train wreck. This is a good example."
To my knowledge, there is only one published paper where a skier was fully instrumented and the data taken was used to reconcile a mathematical model of the physics.
That paper is very complex.
I can't say I understand the physics of skiing but I do understand enough to say much of what I read isn't theoretically sound.
You go, James!

https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/98251/eth-28070-02.pdf

Personally I feel you chaps are rather hard on a guy whose main sin is to keep saying "the laws of physics".
1. He's a ski instructor not a physics prof
2. And this is the biggie - he's not even a New Zealander. Not with that accent. So if he's judged wrong by a jury of his peers us Anzacs can safely disavow all knowledge of him.

Interesting research paper. Depending on how pedantically we define 'not moving inside' it seems to me it makes a point for NZ guy (who's not a native NZr).
The CoM is between the ankles for a fair duration of the turn. 1.5 secs to about 1.8 in that middle transition. At 10 m/s that's about 3 meters or 1 and 1/2 ski lengths. Sure, the CoM doesn't come to a complete stop - it's always moving in or out (thank goodness one of those generalizations is still valid) - but the movement is gradual and between the skis. Keep in mind the error in positioning is stated as being something of the order of 10cm.

Also a question if the skier was at all inside the ideal. Is the vid of the ski runs available?
Here's the data that makes me question.

Small forces through transition as we'd expect. But surprisingly quite a bit of force on the inside ski through the turn. There's a note on this in the paper.

Does this mean that we have to be all pedantic and say we only project 2/3 of our weight to the outside ski?

 

[James]

Personally I feel you chaps are rather hard on a guy whose main sin is to keep saying "the laws of physics".

No, and yes. The whole basis for the presentation is "the laws of physics".
Therefore the phrase is sort of important. Plus the claim the diagrams are all wrong. Blame it on the team. No one objected before it got to a major presentation. That's even worse.
How much sloppiness can you accept? To me it's tiring.

You're right though, it's not like he's teaching surgery.

Don't know about the Swedes, the Norwegians might object.

The Reid 2010 Thesis from Norway
Too bad our physcist/race coach, Jamt, hasn't been around this season. He posted this thesis last year.
-----------------

7.2. Example center of mass and outside ski trajectories through the two analyzed turns taken from a trial on the 10 m course. Trajectories are colored to indicate turn radius parallel to the snow surface. Note that while the outside ski turns nearly continuously, the center of mass has a prolonged phase with little or no turning.

Pg 284
https://brage.bibsys.no/xmlui/bitstream/handle/11250/171325/reid phd 2010.pdf?sequence=1&isAllowed=y
---------------------
Goodness, looks like that slalom skier violated the laws of physics and dove inside.

 

[geepers]

No, and yes. The whole basis for the presentation is "the laws of physics".
Therefore the phrase is sort of important. Plus the claim the diagrams are all wrong. Blame it on the team. No one objected before it got to a major presentation. That's even worse.
How much sloppiness can you accept? To me it's tiring.

You're right though, it's not like he's teaching surgery.

Don't know about the Swedes, the Norwegians might object.

The Reid 2010 Thesis from Norway
Too bad our physcist/race coach, Jamt, hasn't been around this season. He posted this thesis last year.
-----------------
View attachment 72125
7.2. Example center of mass and outside ski trajectories through the two analyzed turns taken from a trial on the 10 m course. Trajectories are colored to indicate turn radius parallel to the snow surface. Note that while the outside ski turns nearly continuously, the center of mass has a prolonged phase with little or no turning.

Pg 284
https://brage.bibsys.no/xmlui/bitstream/handle/11250/171325/reid phd 2010.pdf?sequence=1&isAllowed=y
---------------------
Goodness, looks like that slalom skier violated the laws of physics and dove inside.

Guess that our respective experience is affecting our thinking on this.

In all the CSIA lessons and courses I've taken over the last 4 northern seasons I've yet to have anyone say "what we need you to do is get to the inside faster". And, come to think it, I haven't heard any of the other students being told that either. Includes plenty of candidates for CSIA L3. I've heard the opposite numerous times: "patience, patience" and been taken through a bunch of drills working on that and improved outside ski engagement.

So the NZ preso fits with that. (Then again, no CSIA instructor has ever used the term "laws of physics" out on the slopes - that I can recall.)

Never done any race training so maybe it's different coming from that perspective?


Swedes, Norwegians...how about Scandinavians?

The Brits seem to think it was ok (last few seconds of vid). Different presenter so who knows what's different, but there's that phrase that shall not be mentioned again (1:56)...

By all means have your reply however I don't want to get a circular discussion lock on this thread so I'll focus on a bit of a different aspect of the thread topic if posting further.

 

[Dakine]

Some very interesting discussion and the new (to me) reference is going to take some reading.
e of the papers is about GS type turns and the other is about Slalom turns.
They are very different in radius and duration, obviously.

 

[James]

I've heard the opposite numerous times: "patience, patience" and been taken through a bunch of drills working on that and improved outside ski engagement.

What drills?
For the other, we can drop it. You're ok with the ends justifying saying anything. I don't think so in education, especially if one's job is to teach the teachers. The concept is to create some understanding, not confusion.
Just a little critical thinking by the team could have changed this.
But, that's my other issue with demo teams. It's mostly about the skiing. If you can bs your way through a presentation, ok. Exhibit A there.

 

[Mike King]

Guess that our respective experience is affecting our thinking on this.

In all the CSIA lessons and courses I've taken over the last 4 northern seasons I've yet to have anyone say "what we need you to do is get to the inside faster". And, come to think it, I haven't heard any of the other students being told that either. Includes plenty of candidates for CSIA L3. I've heard the opposite numerous times: "patience, patience" and been taken through a bunch of drills working on that and improved outside ski engagement.

So the NZ preso fits with that. (Then again, no CSIA instructor has ever used the term "laws of physics" out on the slopes - that I can recall.)

Never done any race training so maybe it's different coming from that perspective?


Swedes, Norwegians...how about Scandinavians?

The Brits seem to think it was ok (last few seconds of vid). Different presenter so who knows what's different, but there's that phrase that shall not be mentioned again (1:56)...

By all means have your reply however I don't want to get a circular discussion lock on this thread so I'll focus on a bit of a different aspect of the thread topic if posting further.

@geepers, I think many of the US demo team members would agree with you on this. At least Ballou, Smith, Fogg, and Simpson.

Mike

 

[JESinstr]

Establish, Commit, Patience, Patience

 

[François Pugh]

Comments re NZ video, separate centre of mass (CoM) and ski paths and weight distribution between skis.
It all depends on what type of turn and what type of release/transition.

You can hang onto the old turn until your centre of mass (CoM) and the skis are both travelling across the hill.

You can also, or rather instead, release the CoM from the turn far earlier (I prefer to do it with an early-release cross under transition), but not release the skis from their path so that your body will travel quickly inside the new turn under its own momentum. It's fun to play with this and see how much earlier (closer to the old apex) you can release the CoM while seeing how much farther up the hill you can continue the skis path without tripping yourself up. I imagine it would be no fun if you pushed the game too far - I'm too chicken to push it that far (given myself a fright or two, but never tripped up).