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# Let's talk about over-angulating - Page 16

Quote:
Originally Posted by Tog

How does angulating effect the torque from the ski edge? The force is still at a point beyond the boot edge so there is a torque there no?

Without doing any math I'd say that angulation doesn't change it a lot. The force will be a bit bigger because angulation reduces the turning radius. Also the direction will be a bit different but it will not make a huge change on the torque I'd guess.

Quote:Does it matter if it is on the ankle or the boot. Is the boot not just a mechnical extension of your ankle/foot/leg, the point is that how far your foot/ankle side of boot is from the edge makes a big difference in the ease of edge hold
Originally Posted by Tog

Wow, so finally we're on the same page about the bottom of the foot? Even if it's ball to heel side?

Like I said before, in Pilates, at least the one I went to, they emphasize walking on ball of foot to heel side. - The so called "edge" according to some, You train yourself to do it. Just like you train your legs to not splay out on the lift but go straight ahead. An issue for some more than others.

Also, skates are not necess on the center line. For fig skates that can all be custom made how much offset there is.

jamt, I agree about the torque on the boot and not the ankle, so...

If you have a wide ski edged on hard snow, is not that torque always present on the boot? Even if angulating? How does angulating effect the torque from the ski edge? The force is still at a point beyond the boot edge so there is a torque there no?

Quote:
Originally Posted by Jamt

Sorry to say but I don't like that part of ultimate skiing at all. The force on the ski boot causes torque on the ski boot, not the ankle. I may have a totally relaxed ankle and oppose the torque with muscles higher up. For the ski boot to be in balance the forces need to balance but the snow doesn't care if the opposing forces come from under the foot or higher up in the shaft. The snow doesn't care what causes the boot to be in balance or have the appropriate platform angle.

'There are other reasons why tipping the foot joint is a very good idea, but it has little to do with what Ron says.

Well of course the snow doesn't care, snow has no feelings. I always find it strange when people refer to inanimate objects not having feelings , duh? but your ability to manage force; balance and feel confident on hard snow is defintley affected by the distance your ankle is from the edge.

I ski in a non posted footbed with the navicular area of my boot slightly enlarged to allow micro balance adjustments with my foot, rather than using gross motor movements of larger muscles up the food chain to adjust balance.

Edited by Atomicman - 1/28/14 at 1:30pm
Quote:
Originally Posted by Atomicman

Well of course the snow doesn't care, snow has no feelings. I always find it strange when people refer to inanimate objects not having feelings , duh? but your ability to manage force; balance and feel confident on hard snow is defintley affected by the distance your ankle is from the edge.

I skiin a non posted footbed with the navicular area of my boot slightly enlarged to allow micro balance adjustments with my foot, rather than using gross motor movements of larger muscles up the food chain to adjust balance.

I agree Aman, that's why I said "'There are other reasons why tipping the foot joint is a very good idea, but it has little to do with what Ron says."

Edit. The "snow doesn't care" is just another way of saying that the snow-ski interface is fully determined by the size and direction of the according forces distributed over time, not how they are produced.

Sort of the reverse of the guy stuck in avy debris.

Quote:
Originally Posted by Jamt

I guess it depends on what "require angulation" means. My take what that is the amount of angulation in your body you reguire to reach certain edge angle.

Sounds good to me. I like to keep it simple - keep the upper body more or less vertical and the skier should be able to balance over the outside ski in most situations.

Even very extreme angles where the hip is touching the snow and the inside ski lifted.

Uhmmm I don't think everyone is disagreeing with me, some of you are. aside from jamt, the people who are disagreeing pretty much always disagree with me so its par for the course. some of you seem to misunderstand me, but maybe you didnt try that hard either.

Anyway you guys keep walking and I will keep tipping. Right now I have to drive to Jackson hole. Cheers.

Torque and pressure distribution are simple physics. I think confusion arises in a discussion like this when people mix frame of reference and action vs. reaction. My smart alecky way to see if a newbie understands the physics they are talking about is to pose an apparent paradox: Per Sir Isaac, action and reaction forces are exactly the same but opposite in direction, therefore the net force is zero. It then follows that the skier must be either standing still or moving at constant speed along a perfectly straight line, no matter what.

A sophisticated person, possibly without much understanding of physics, may answer: But of course, in the frame of reference of the skier, he is not moving. True by definition, but it offers neither insight nor clarity, just useless words.

Of course there is no paradox, action and reaction are forces acting on different objects. When one wants to look at the motion of an object, the simplest thing is to look at the forces acting on that object, the skier in this case. There are cases when it is convenient to switch FoR. But that's like jumping off a 50 ft cliff, better left to experts who know what they are doing. Talking about both centrifugal and centripetal forces in the same analysis falls into this category, except there is no bodily harm when done incorrectly, unlike cliff jumping.

So, for a skier, all that matters are gravity, which can be simply represented by a single vector originating from the COM pointing downward, AND the force acting on the skier which is a vector S starting from the contact of the snow and ski. This vector can be decomposed into an infinite number of pairs of two components. Most of them serve no useful purpose. One useful decomposition is a vertical component and another parallel to the surface of the slope. The former determines the up, down acceleration of the COM, the latter the turn radius or trajectory on the snow. IMHO about skiing, all technique and movements are to manipulate the magnitude, direction, AND starting point of S. If S doesn't pass through the COM, there will be a torque rotating the body, sometime with exciting consequences, like a WC crash.

For a given S and edge angle (not independent), geometry shows that less angulation is needed to line up S with the COM if the ski is wider as Jamt claims.

If contact between ski and snow is a few mm at the edge, then the force distribution on the foot, i.e. pressure, will be strongest at the BTE and weakest at the LTE of the foot as BTS says. The closer the BTE to the ski edge, the more lopsided the distribution. If still in doubt about it, put a stiff ruler on a firm mattress and press it down with your finger. The difference of pressure distribution along the ruler as a function of where your pressing finger is should be obvious.

How this helps skiing is not clear to me, but the physics in discussion is only controversial to those who have no formal exposure to classical mechanics, I daresay.

FWIW I don't disagree, skiing and walking are clearly not the same, there are components of the two movements that are similar though.  wish I was driving to Jackson.

At some point it would seem, whether through realization of our own movement or actually looking at these photos the notion that the upper body stays vertical without mobility is impossible, beautiful pic above demonstrates it well, forward rotation of the right side pelvis, elevated L pelvis, elongated right ribs, compressed left ribs and an upper thoracic spine counter rotated relative to the pelvis.  How can anyone achieve that body orientation without dynamic mobility above the hips. And just to reemphasize, outside leg driving in an extension pattern with hip internal rotation, the outside leg firing in the flexor pattern trying to resist the COM being driven into the ground and keeping the inside foot in the right positon(the outside half of foot).  Just so happens the same patterns occur with every step, which is why we heel strike on the outside of the foot, propogate through the center of the foot in mid stance when the GRF is the greatest and push off on the inside half of the foot at toe off.

Quote:
Originally Posted by borntoski683

Anyway you guys keep walking and I will keep tipping.

I like it!

Quote:
Originally Posted by ChuckT

How this helps skiing is not clear to me

Frankly I find these physics discussions to be a waste of time unless you are working on designing a ski simulator.

Anyone here working on a ski simulator?

Quote:

How can anyone achieve that body orientation without dynamic mobility above the hips.

They can't.

To the observer it looks like a stable upper body. But for the athlete it takes incredible core strength and flexibility to move the upper body to the outside creating the illusion of stability. Literally a massive contraction of muscles on one side timed with relaxing/stretching muscles on the other side.

Quote:
Originally Posted by skiatansky

Frankly I find these discussions to be a waste of time unless you are working on designing a ski simulator.

Anyone here working on a ski simulator?

I'm. An imaginary one in my mind to help me visualize (and talk about) skiing when I am not on the snow which is 99.9999% of the time. I actually learn some good stuff from discussions like this that I believe will help my skiing (he he will try to get some video to confirm or refute this ).

Quote:
Originally Posted by Jamt

Quote:
Originally Posted by borntoski683

Jamt, draw the same picture with the skis having the same edge angle and tell me which one is more inclined.

Here they are with approximately the same edge angle. With the super wide ski you have to angulate towards the inside to keep the CoM above the edge.

The moments are proportional to the distance between the joints and the force vector, thus with the wide ski the torques are larger. This is not always the case though.

In the following picture the sideways bending moment is large in the ankle, but smaller in the knee: So for a person using a lot of knee angulation a wider ski may be better for the knees.

What I don't get is talking about the knee/torque. I see it from the diagrams above. However, if a ski is say 120mm and is past the edge of the boot, is there not a constant torque from that moment arm -edge of ski to boot edge that acts on the boot which acts on the knee?

Are you saying that this is somehow cancelled out by aligning the com over the edge? I believe that was bts's point above. I don't see how that's possible.

Quote:
Originally Posted by ChuckT

I'm. An imaginary one in my mind to help me visualize (and talk about) skiing when I am not on the snow which is 99.9999% of the time. I actually learn some good stuff from discussions like this that I believe will help my skiing (he he will try to get some video to confirm or refute this ).

I'm 99.9999% positive it won't help more than .0001%

Instead invest in a variety of balance improvement gadgets. Use them daily and the next time you are on the snow you should notice improved balance on the skis which will lead to better skiing.

Quote:
Originally Posted by Tog

What I don't get is talking about the knee/torque. I see it from the diagrams above. However, if a ski is say 120mm and is past the edge of the boot, is there not a constant torque from that moment arm -edge of ski to boot edge that acts on the boot which acts on the knee?

Are you saying that this is somehow cancelled out by aligning the com over the edge? I believe that was bts's point above. I don't see how that's possible.

What you are missing is that there is a torque in the hip aswell which will partially cancel the torque coming from the below. If the force vector passes through the knee they cancel each other completely. Perhaps this is easier to realize in the for-aft plane. If you stand in an athletic stance and fold your upper body forward you will eventually have no torque in the knee and the quads relax.

Quote:
Originally Posted by skiatansky

Frankly I find these physics discussions to be a waste of time unless you are working on designing a ski simulator.

I am the kind of person who asks why if someone wants me to drink cool aid for no apparent reason.

There are a bunch of  physics things done to great detail. I sent jamt a link last season on a very long paper on finite element analysis of a ski turn. It is way beyond me. @Jamt did you look at it?

Here's one using gps to analyze gs turns on a larger scale. starts a pdf download

(Done more I think for the sensing system)

"Determination of External Forces in Alpine Skiing Using a Differential Global Navigation Satellite System"
Matthias Gilgien 1,*, Jörg Spörri 2, Julien Chardonnens 3, Josef Kröll 2 and Erich Müller 2013.

Quote:
Originally Posted by skiatansky

Instead invest in a variety of balance improvement gadgets. Use them daily and the next time you are on the snow you should notice improved balance on the skis which will lead to better skiing.

Hey, why choose, I'm standing on a bosu ball at my desk as I am typing this :-D I do that 6 hours per day.

Quote:
Originally Posted by Jamt

I am the kind of person who asks why if someone wants me to drink cool aid for no apparent reason.

Fair enough and I agree.

I was commenting about the likelihood of a physics discussion improving one's skiing rather than being used to support a questionable theory.

Quote:
Originally Posted by slider

Quote:
Originally Posted by Jamt

Quote:
Originally Posted by Tog

What I don't get is talking about the knee/torque. I see it from the diagrams above. However, if a ski is say 120mm and is past the edge of the boot, is there not a constant torque from that moment arm -edge of ski to boot edge that acts on the boot which acts on the knee?

Are you saying that this is somehow cancelled out by aligning the com over the edge? I believe that was bts's point above. I don't see how that's possible.

What you are missing is that there is a torque in the hip aswell which will partially cancel the torque coming from the below. If the force vector passes through the knee they cancel each other completely. Perhaps this is easier to realize in the for-aft plane. If you stand in an athletic stance and fold your upper body forward you will eventually have no torque in the knee and the quads relax.

Yes it makes sense in the fore/aft plane when static.

From side edge:

Ok, so I see they could cancel out from the edge, however, if there's a torque on the tibia laterally (in lateral direction)  due to the ski edge being far from the boot edge, then this is neutralized by the hip transmitting a medial force on the tibia. But that has to go through the meniscus, no? Isn't that more wear in the knee joint due to that? Shouldn't there be an increased pressure in that area of the knee?

Or am i missing something really basic yet again?

Quote:
Originally Posted by skiatansky

Sounds good to me. I like to keep it simple - keep the upper body more or less vertical and the skier should be able to balance over the outside ski in most situations.

Even very extreme angles where the hip is touching the snow and the inside ski lifted.

Quote:
Originally Posted by skiatansky

They can't.

To the observer it looks like a stable upper body. But for the athlete it takes incredible core strength and flexibility to move the upper body to the outside creating the illusion of stability. Literally a massive contraction of muscles on one side timed with relaxing/stretching muscles on the other side.

Isn't the idea to keep it simple :)

It is a shame these discussions can't benefit from dialogue to either side of the fence, it must be an internet thing, I can only assume in person these would be much better conversations, is this even a conversation?

Having read a lot in this subforum, this is where it seems peeling back layers is done, where details that never are said to cllients are teased out.  so the very notion that keeping it simple may not be best for learning a very complex process.  Why not just tell someone to stay "more or less vertical", isn't that something that even needs to be taught, because if your not, your more or less horizontal right.

the best part about balance and movement control with gravity is feeling just how little effort we need to be successful, while on a certain level it is one side contracting and one side relaxing, maybe knowing what those are makes it easier to look at someone or even ourselves who may be having difficulty being more efficient.

you can't make something simpler, understanding it though makes teaching it more simple, or something like that

tog- the more neutral the joint the more the structures on the outside of the joint can absorb the force, the further from neutral a joint is positioned the tighter the supporting structes get and they lose the ability to transfer the force beyond that point, it s double shitty situation, increased stress and strain at the joint and higher joint compression on the internal structures/cartilage, etc

Quote:
Originally Posted by skiatansky

I'm 99.9999% positive it won't help more than .0001%

Instead invest in a variety of balance improvement gadgets. Use them daily and the next time you are on the snow you should notice improved balance on the skis which will lead to better skiing.

No doubt. But I find such training activities very boring. I can't bring myself to do them, and drills, with any regularity. I enjoy doing things that require balance like skating, MTB when I can, but can't afford much time for them either.

I think my skiing has benefited from my better understanding of skiing in the last year. But to be certain, I will have to do some real experiment and get video to confirm (or refute - one can never be sure). If my next video shows observable improvement, it has to be from all the thinking and yakking because there is not enough time to hardwire any targeted movement by practice. We shall see.

Quote:
Originally Posted by Jamt

Sorry to say but I don't like that part of ultimate skiing at all. The force on the ski boot causes torque on the ski boot, not the ankle. I may have a totally relaxed ankle and oppose the torque with muscles higher up. For the ski boot to be in balance the forces need to balance but the snow doesn't care if the opposing forces come from under the foot or higher up in the shaft. The snow doesn't care what causes the boot to be in balance or have the appropriate platform angle.

'There are other reasons why tipping the foot joint is a very good idea, but it has little to do with what Ron says.

This conversation is very interesting, and I'm not trying to add fuel to the fire......

I have been helping with a research project the past few years with a Phd in Anatomical Physics, his nickname is Doc.(not very original I know)  Doc has opened my eyes to a lot of things about skiing, in which I had not thought of.  He has worked with various sports from pole vaulting, wrestling, running, football, etc. (he taught me why the stiff arm works so well in football, and it's the same reason a boxer needs to land the jab).
I am still far from the overall expert the best technique, but I do have 30 plus years of race or coaching experience at what most would consider to be a very high level.  Doc's premiss is that the best athletes in any sport will already be doing 95% or more of the movements in the best way possible for the human body to perform those tasks when looked at in terms of energy exerted, and anatomical alignment (aka strongest body alignment position or movement).
We did a lot of testing, and you claim that your ankle is totally relaxed, and you oppose the torque with muscles higher up.  What muscles move your foot around your ankle joint?  They are all higher up.  In addition you are flexing your boot forward (the way it was designed, the muscles higher up in your leg are causing your ankle to flex, push back, etc...).  During turn initiation the Anterior Tibial, the  Peroneal Tibial, Peroneous Brevis and the Flexors (Digitorum Longus, and Hallucis Longus) were all under very heavy use when we looked at 6 different NorAm Cup racers.  They were even used but to much less of an effort in the 6 skiers we tested that were level ii or level iii, we did see a correlation of the more advanced skiers using these muscles more, than those who were closer to the beginner stages.  The findings (which will be published in the next 6 to 10 months) show significant use of the ankle in skiing, the boot does not remove the use of the ankle, but it merely stabilizes it.
In on tight hard turns the less skilled tend to use their body mass moving forward to get force onto the shovel of the ski, while advanced skiers are flexing the ankle and driving flexors very hard while the body mass remains in a more stationary place.

Don't ask me the name brand of the equipment used (I didn't help put the sensors on, and I was only their to assist on the hill to set up turn paths, and instruct the participants in what we wanted them to do on the slope).  In a nutshell though, it measure the electrical output to the different muscles while the skiers did different activities.  The results proved the boot is merely a support for the foot, ankle, and lower leg, but we are using forces on the foot and not as relaxed as I would have thought before, or have been told to try and be.  The US Ski Team did issue a grant to support this study, fyi and all of the Nor-Am Cup racers were on the D-Team.

The biggest thing that I learned though was the relationship of ankle to knee to hip to shoulder, and if you become out of the correct alignment, you become very weak, and will not be efficient in your skiing.  I have asked for some diagrams from Doc, I don't know if he will share them with me yet or not.  I am enjoying reading all of the different thoughts on this subject of over angulation, but at the same time wondering if we should start one about alignment.

Thanks to everyone contributing for keeping me intrigued and my mind occupied.
Quote:

Why not just tell someone to stay "more or less vertical", isn't that something that even needs to be taught, because if your not, your more or less horizontal right.

I would say that is a very common instruction. And yes, it definitely needs to be taught. Most skiers lean into the turn.

Quote:
Originally Posted by ChuckT

But I find such training activities very boring. I can't bring myself to do them, and drills, with any regularity.

In that case don't be surprised when you plateau. The best skiers make time for these boring and mundane activities because they work.

Good for a warm up run. Just like stretching. Not many do that either.
Quote:
Originally Posted by skiatansky

Fair enough and I agree.

I was commenting about the likelihood of a physics discussion improving one's skiing rather than being used to support a questionable theory.

Actually, a proper physics discussion, emphasis on "proper", cannot be used to support a questionable theory. It will show such theory to be indeed questionable. The most rigorous of all sciences, it is often abused by people without a firm grasp of the subject matter to put a veneer of scientific rigor to their belief. Fortunately, such pretensions are usually easily seen, unlike in sociology or political science.

The funny thing is, IMO, not everything about human movements, learning, and adaptation is about physics (but they must not contradict physics, though). No genius can balance solely on their calculations of torque and force. Neither does any sane coach try to explain skiing to a child with centripetal or centripetum. There is a huge value in having hands-on experience. It is far better to communicate the feeling, the sensations, the practical matters to students either on line or in person than to put forth questionable theories using wrong physics.

Quote:
Originally Posted by skiatansky

In that case don't be surprised when you plateau. The best skiers make time for these boring and mundane activities because they work.

I will be disappointed but won't be surprised. There is no free lunch. I am merely looking for a better deal, for me . There is no guarantee such a deal exists.

I am a recreational skier who had reached a plateau for some time. I noticed that there is something fundamentally different between how I ski and the skiing I admire. If I ski a lot more, I will get a little smoother, can carve with a little higher edge angle, but that would be it no matter how hard I do drills, how much more refinement I get with balance and practice.

I am most certainly not at a level that I need to make all the "right" movements expertly to improve. My plateau, I believe, is due to my lack of real understanding of the dynamics, or physics if you will, to execute the movements appropriately; my body is too old to instinctively learn new tricks by itself. Knowing not just what and how, but why usually helps make things stick to me. I am also eager to apply zenny's ideas on using sensory feedback. We shall see with video if I can break through my current plateau.

If indeed you are right that the improvement is at most 1% (already 4 orders of magnitude higher than your estimate ), it still won't be detectable and as good as no improvement. In that case, I shall table any thoughts of self coaching (with online help of course) and start scheming to get to a camp by hook or by crook. But right now, I remain hopeful.

Incidentally, are you an instructor skiatansky? Got video  ? (just kidding - I see the logic in everything you say. The romantic part of me hopes skiing life needs not be so strict and disciplined)

Edited by ChuckT - 1/28/14 at 4:43pm

We've gone in several directions over the 16 pages here. The original question of how to cure excessive hip dumping needs to be repeated and the answers rendered down to workable real world solutions. ones based on understanding all the implications of all the possible causes.

1. look at the equipment causes that might be present. Do the simple adjustments if you are qualified to do those adjustments. If not get the student in touch with a qualified boot person who can fix those issues. It's surprising how little time gets spent on this. Especially in the rental world. Mosh at one point in time had a shop inside the beginner corral because those rental boots. Another important but often overlooked equipment idea is if the rental fleet lacks the tuning that would allow for better edge grip. While we can't ski around with a lot of edge tuning stuff in our pockets, maybe a pocket tuner and stone of some sorts might make sense. It all depends on having access to a shop able to turn around a set of skis quickly. Overnight tunes are quick but extensive work often takes a lot longer. So give your tuner enough time to do what needs to be done.

2. look at habitual off the snow movements. Joint biases exist in everyone's life. We can't help developing habitual movements in our daily life. If those habits include flexing in the hips and that translates to using excessive hip angulation on the snow, eliminating that habit on the snow is much more involved and difficult.  While some hip and core movement is part of the dual paths idea, excessive movements in the core and the stances produced by that sort of joint bias needs to be investigated. Past knee, spine, or ankle injuries might be the root cause since protecting that weak joint is quite common in our everyday lives.

3. Poor technique based on antiquated ideas like form over function mantras so common back in the Arlberg days , avoiding inclination (especially "unintentional" banking) at all costs, starting the turn with a rotary push off release move and projecting the pelvis uphill, projecting the core too far inside too soon, or to a point too late in the upcoming turn, adherence to a concept like a vertical torso when the appropriate amount of lateral range of motion needed for a turn exceeds the lateral" reach" of the legs, too much blocking with the legs typical in unwanted vaulting (VB absorbing problems), Excessive upward extension prior to the fall line that disrupts the ability to maintain edge purchase during the shaping phase and moving all the strong edging efforts to the finishing phase of a turn, and of course imitating a picture they saw and mistakenly believing skiing is about posing in a position like we see in post 456. Imagine if someone chose to imitate the following pic in the mistaken assumption that it represents the concept of proper inclination.

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