Skiing isn't about physics!

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Skiing isn't about physics!

Postby h.harb » Thu Apr 09, 2020 1:19 pm

Well said, just remember the famous Mark Twain quote: "removing all doubt"

Physics doesn't make movements or good skiing. Just look at Ron LeMaster, he talks physics all the time, he can't ski and he's very confused, but his Bulls--t baffles brains, just check out how often they quote him on Epic.


This is from a post I put up about 7 years ago. Skiing is about movements, learning what part of your body you need to move and do it in the right order, it's not physics. Physics and the relationship to skiing are academic, not practical. Ron Lemaster wants to make it about physics because he can write it down and draw diagrams that explain the environment and external force reactions. Even with that, he doesn't do it well. Why? Because he's justifying the PSIA methodology, it's like listening to Trump on the tax cut trickle-down economics, all bullshit. People who want to constantly relate skiing to physics, can't teach and can't ski.
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Re: Skiing isn't about physics!

Postby blackthorn » Fri Apr 10, 2020 11:41 am

HH - I think I understand what you are saying, and don't generally disagree.

However for me, understanding the physics explains why the PMTS movements work so well. But indeed it is not a necessary component.

One explanation might be that movements are about how, and physics are about why. And indeed each aspect can be done badly or well.

A lot of us are getting cabin fever down here in New Zealand - locked in by Covid.
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Re: Skiing isn't about physics!

Postby ToddW » Fri Apr 10, 2020 12:53 pm

Blackthorn,

I understand that some skiers need to view skiing from a "physics" angle. But I'd caution you about this. I was smuggled into a PSIA-E evening briefing on their new tech manual during the Eastern Academy several years back. My job was to call out the demo team for the nonsense they were spewing and their misuse of "physics", but another physicist who was a level 3 in Eastern beat me to it. He was not kind, especially to the demo team guys from Eastern.

I know lots of ski instructors and coaches, and I've never heard one of them invoke physics and get things right (except Diana.) Ron LeMaster worked (as a computer programmer iirc) in the UC Boulder physics department at one time, but his books are full of physical nonsense. I've also heard practicing engineers mis-invoke "physics" to explain their skiing,

I spent ten intense years training to be a physicist, but my knowledge of physics has only helped me half a dozen or so times in my skiing journey (and mostly related to alignment technician training.) Talk about a poor return on investment! And it's hindered my understanding many times when a coach has used words like energy or momentum in accord with English vernacular rather as a physicist or engineer uses them.

PMTS in many ways is about a leap of faith. Max_501 has said before to just do exactly what Harald says. Geoffda has posted before that conceptual understanding sometimes comes only from being able to do it at which point it becomes clear. I believe in trying to do exactly what Harald says -- and got banned from the pugski forum for saying that Max's advice -- do exactly what Harald says -- was the best skiing advice I ever received (best ski advice or tip was the thread topic.)

Focus on the leap of faith and understanding will follow.
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Re: Skiing isn't about physics!

Postby h.harb » Fri Apr 10, 2020 3:22 pm

Good post!

Diana and I talk about the physics of skiing often. But it's to further qualify and validate what we use in our PMTS system, not to try to impress skiers or instructors. I agree with Todd, when physics is thrown around I get confused because the terminology is often used incorrectly. The old saying is, "If you not sure, and you want people to not think you are stupid, keep your mouth shut or you could prove you are.

Ron Lemaster is a case in point, he's a computer guy who uses PSIA methods in his skiing, and tries to justify them by making up his own physics.
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Re: Skiing isn't about physics!

Postby blackthorn » Fri Apr 10, 2020 5:21 pm

I don't disagree with the comments in these last two posts.

I certainly would not set myself up as an expert in physics, teaching, or skiing, or in anything really. I remain student in these, and even regard myself as one in the area of my own professional expertise.

I remain committed to the principles of PMTS - not that this need worry anyone really, and my journey in understanding movements, and their underlying physics have been personally validating.
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Re: Skiing isn't about physics!

Postby h.harb » Sat Apr 11, 2020 2:11 pm

Most of the best ski racers in the world didn't get physics degrees. But they are physics experts, better than Physics professors, I guarantee you. How can I say this? Well, watch them ski, they know precisely how to angle a ski, let it load or bend and release the forces at the precise moment. This is the application of movement precisely. This is feeling or knowing the physical world better than anyone. But they can't explain it.

In fact, they can't even explain how they do it, let alone explain the forces. So how does technique evolve?

It doesn't evolve with people like Ron LeMaster and there are a number who have tried, John Howe, Uris Wagner, and others have written books about it. I knew both these guys, John especially, as I coached him as a Master racer. At that time I knew a little about physics from my physics courses. But I soon learned, John who was an engineer and designed skis, had no idea how to apply his physics and engineering to his skiing. In fact, Diana who is brilliant, she achieved her Master's degree in Aerospace from Standford in 18 months couldn't apply her knowledge to skiing. Her skiing didn't evolve out of the academic study of forces. She did know early on however with her training and education that the movements or techniques that PSIA trainers were telling people were physically impossible.
So again the quaestion I'm asking is: How how does ski technique develop? One thing I know, don't expect the physicists to develop it.
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Re: Skiing isn't about physics!

Postby Jwthe2nd » Sun Apr 12, 2020 12:47 pm

Physics can help to understand the execution of movements. I realized that allowing the skier to travel along the fall line results in smooth and fluid skiing. For example, a faster release is used in steeper terrain. This permits travel down fall line smoothly. This helped me to feel the release better and to vary the duration of the release with changing slope.
Thanks for putting out so many great videos.
Last edited by Jwthe2nd on Thu Dec 17, 2020 8:14 pm, edited 1 time in total.
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Re: Skiing isn't about physics!

Postby noobSkier » Sun Apr 12, 2020 1:53 pm

ToddW wrote:PMTS in many ways is about a leap of faith.


I don't think it's a leap of faith, there are too many of us showing good results. The repeatability is well established at this point. You are 100% right about the physics, it's totally useless from a learning perspective. I'll admit at times in my journey I've over indulged in the physics aspect but its never catalyzed tangible improvements. Now I just see it as an indicator for movement deficiency: if you are dwelling on the physics, you are doing it wrong...time to take video :)

h.harb wrote:People who want to constantly relate skiing to physics, can't teach and can't ski.


pure gold
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Re: Skiing isn't about physics!

Postby h.harb » Mon Apr 13, 2020 12:05 pm

I'd like to see some videos of those who say they learned by physics. Let's see if their use of physics to learn created efficient movements? Talking center of mass movement is horse shit the center of mass has no movement muscles. CM talk is total PSIA CSIA bullshit. We don't mention CM or CG in teaching skiing. We do in the physics of skiing discussion. I rely on Diana's experience with PSIA. She is brilliant, knows more about physics than any PSIA member and she couldn't get it when they started trying to get her to ski their way. She was confused because they had no idea how to use the physics of skiing to teach. Now she can out ski any Demo Team member. Without using physics to relate to her skiing.


Edit added:
However, I'll add this comment, talking center of mass movement demonstrates one, only one, because there are many, of the limitations and flaws of PSIA instruction. If you are focused on C of Mass, you are relating to outcomes, and that is what PSIA teaches, outcomes. Outcomes don't teach a skier anything but it sure frustrates the hell out of them. Image an instructor telling you this is how you should ski when you get it? He never tells you the how or the why. That is PSIA. PMTS teaches movements that give you the outcome you want. Totally different system. In PMTS there is a body part and a movement for every body part. You can learn these movements for every part of the turn and PMTS instructors know how to have you access those movements. Completely different systems.
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Re: Skiing isn't about physics!

Postby NoCleverName » Tue Apr 14, 2020 3:57 am

I believe there is only ONE thing from a physics standpoint that is important in skiing: once set on edge, the ski will take a circular path on its own. Your job, as a skier, is not to do something stupid to disrupt the ski from performing the turn for you.

From this theorem there are of course corollaries. The ski can't turn if it's not in the snow. The way to avoid disrupting the ski is to stay in balance over it so as to not create disrupting forces. There are probably more but they are very simple and speak directly to PMTS.

I am reminded of the skiing robot (the video was linked somewhere here). Obviously some engineers used these simple principles to make it work. If I remember it looked pretty PMTS-like.
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Re: Skiing isn't about physics!

Postby h.harb » Tue Apr 14, 2020 7:21 am

I'm trying to point out how you teach and what gets results for the student. I'm not talking about theory here. Physics is theory and skiing forces explanation in a physical environment. This isn't what is relevant or used in teaching with PMTS.
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Re: Skiing isn't about physics!

Postby NoCleverName » Tue Apr 14, 2020 9:03 am

I suppose that is my point, too. There is nothing physics that is going to inform your skiing as PMTS already embodies the practical application of it.
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Re: Skiing isn't about physics!

Postby h.harb » Wed Apr 15, 2020 2:19 pm

Right, Bruce. I hope you are getting through this horrid time with the virus OK?
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Re: Skiing isn't about physics!

Postby NoCleverName » Thu Apr 16, 2020 6:22 am

In Bartlett NH social distancing was already a way of life 8)

There are very very few cases up here...but as it is a tourist-dependent area there is a lot of fear when the lockdowns are released elsewhere. Here pretty much everything is already closed (fortunately it's also "mud season" so there was little business anyway). But the problem could be a double-whammy of having to stay closed while everything else opens up. Even as a tourist area a few strange things are going on when it comes to non-locals. We have a friend from Mass who stays at her place up here, but we buy her groceries so she doesn't have to traipse around with Mass plates. Another small business doesn't put out their "Open" sign so that out-of-towner's don't come in; the locals know they're open.

BTW the ravine was closed by the Forest Service some time ago. The avalanche danger is pretty high up there anyway.

...but getting a lot of yard work done and many others are getting around to cleaning out their garages. :lol:
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Re: Skiing isn't about physics!

Postby agent00F » Tue Sep 22, 2020 1:33 am

h.harb wrote:
Well said, just remember the famous Mark Twain quote: "removing all doubt"

Physics doesn't make movements or good skiing. Just look at Ron LeMaster, he talks physics all the time, he can't ski and he's very confused, but his Bulls--t baffles brains, just check out how often they quote him on Epic.


This is from a post I put up about 7 years ago. Skiing is about movements, learning what part of your body you need to move and do it in the right order, it's not physics. Physics and the relationship to skiing are academic, not practical. Ron Lemaster wants to make it about physics because he can write it down and draw diagrams that explain the environment and external force reactions. Even with that, he doesn't do it well. Why? Because he's justifying the PSIA methodology, it's like listening to Trump on the tax cut trickle-down economics, all bullshit. People who want to constantly relate skiing to physics, can't teach and can't ski.


The problem with using physics in sports generally is that the body biokinetic system is too complex to be taught/used in any tractable manner to non-physicists. For example, just the knee which is one of the simpler joints is a 4 link system, the analysis of which is non-trivial even in a professional engineering setting.

It's only possible to highlight a few principles to teach some intuition, but that's more as a pedagogical aid so some process/technique "makes sense", rather than any attempt to discover technique from first-principles.

It's a bit more feasible to understand skiing from the gear side because the equipment is relatively simpler than the human body, like the geometry of how much tipping/angle is necessary to get an approximate carved radius, but if it were that simple all manufacturers would make perfect gear without testing/feedback which is obviously not the case.
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