It’s not Stupid

[LiquidFeet]

....Something about skating feels a lot like parallel turn initiation, just a slight difference in how you handle the inside ski. Maybe it just gets you used to quickly shifting your weight.

Skating gets you lifting one ski while propelling off the other, so yes, there's a rather dramatic weight shift involved.
The body is projected ahead of the propelling foot by this extension, which gives the skier a feeling of immediate control over the turn.

Skating down hill feels very very different from sliding in a wedge with skis somewhat flat and turning both skis (rotating them) to point downhill to start a turn. It can be thrilling.

Skating to start turns means you start turns with a dramatic extension of the new outside leg. So skating is a way to learn to make extension turns, where the skier projects the body down the hill. Another way to start turns is by flexing the new inside leg to get its ski to let go of the hill. Flexion turns have the skier letting go, giving in to gravity and momentum momentarily as the turn starts, allowing those forces to move the body down the hill. These two feel quite different when done as described.

Extension turns make the skier get tall between turns, while flexion turns keep the skier low. There are benefits to both. Well-rounded skiers know how to do both initiations.

Much has been said about the relative value of these two ways of starting turns ... and about the value of the third way, rotating the skis when flattened to point down the hill.

People argue.

 

[T-Square]

I inadvertantly discovered that beginners can learn to ski pretty much parallel, skipping the wedge altogether, on day one if they are taught with a skating progression. This needs to be taught on downhill terrain where they can't gain speed no matter how hard they try, or they will not feel like they can trust the instructor and fear will invade the lesson.

I discovered the beauty of a skate-progression on a below-zero day. My group's rental skis did not have cold wax and the skis wouldn't slide. My usual beginner progression was producing unimpressive results as they all struggled to move downhill. In my demos I'd have to skate to get to where I wanted to start the demo. At some point about midway through the lesson I was leading them down the hill and turned to see what they were doing behind me and holy g'mollie they were all skating towards me, very competently. They were copying what I was doing, not what I was teaching. We all celebrated how that was working, got a good laugh, and I continued the lesson with the emphasis on skating. They all ended up feeling very much in control and were skiing parallel at the end of this 1.5 hour lesson, with both skis staying on the snow between turns.

I've since tried this on normal days with beginner groups. It doesn't work on the beginner terrain available to me because of the fear factor.

I used it once with a middle-school never-ever private lesson on that same terrain, on a day when the skis would slide, only this time I had my student skating downhill in a wedge. She caught on immediately and clearly loved the feeling of control the skating and gripping skis gave her. She learned to use turn shape for speed control very well by the end of the one hour lesson. But she was still in a wedge, and I haven't repeated that progression since with adult groups. It's worth a try though.

Anyone else here used this kind of approach to teaching beginners?

BINGO!

Glad you discovered this as a teaching method. I’ve begun to use more skating in beginning lessons. Get your student on short skis and start playing. People learn by doing and the more doing you incorporate into your lesson the faster people learn. Short skis (120 to 135 cm), flat terrain or very gentle terrain, then skate. They will feel how the ski interacts with the snow. I’m a big proponent of direct to parallel and allowing wedges to happen.

 

[Seldomski]

The skating drill I did was part of an advanced lesson. There was also some emphasis on rolling from little toe to big toe edge during the skate stride. When you do this, you definitely get the toppling sensation down the hill.

IDK if you can get this edging emphasis into an intermediate lesson specifically. Maybe an intermediate would do this by accident and not be sure exactly what happened?

 

[mister moose]

Something about skating...Maybe it just gets you used to quickly shifting your weight.

Sometimes. Skating is (almost) the only way to get people to move to (over) one ski. People sometimes push off onto the ski without moving their body over the ski, so they thump right back down on both feet. Sometimes no feet come off the ground, ever, in their skate. Different things work for different people.

Skating well, or skiing dynamic turns, or doing well in the bumps, or being able to recover well all require strong single leg skills. When a maneuver needs a dominant leg, you aren't going to do it well on training wheels with both feet. And each of these have components of the other. So practicing one seemingly unrelated maneuver can cascade benefits into other places.

Because learning to move the COM to the inside requires a strong[er] outside leg, many skiers trying this that can't move to a dominant leg find lots of trouble. It feels wrong. So I believe that in many cases getting over what seems to be a single stumbling block is not about "that one thing". It's many things.

If I could only intitiate sooner....
If I could only turn in powder the way I do on packed slopes...
If I could only lose that stem...
If I could only keep my speed steady...

To advance in skiing, stop looking at THE ONE and start looking for THE MANY.

 

[mister moose]

​

Getting the COM to move in beyond the inside foot takes a new level of skill by the intermediate skier. Why? Because once the COM moves beyond the inside foot, dynamic balance must exist.

Yes, and we can demonstrate that in our normal dryland activities. @Josh Matta shows that we do it when we bike.

Right. But my gut tells me that while it is one thing to do it on the bike, it is quite different to be the bike.

 

[karlo]

you're refining your own internal mental model for the next time you try to think through something, but this can actually be a really useful tool for the right person.

A mental model is a huge plus. And, that model can change as one advances. Whatever the model is, it’s something by which we can affirm our understanding at the time. It’s when we see or experience something that deviates from the model that we have another opportunity to learn.

Something about skating feels a lot like parallel turn initiation, just a slight difference in how you handle the inside ski.

Skating gets you lifting one ski while propelling off the other, so yes, there's a rather dramatic weight shift involved.

The skating drill I did was part of an advanced lesson. There was also some emphasis on rolling from little toe to big toe edge during the skate stride. When you do this, you definitely get the toppling sensation down the hill.

The motion of skating is huge. It’s that rolling from one edge to the other (little to to big toe). It’s that use of the ankles. It allows quick transfer fromedge to edge, nimbleness and power. Try it standing on one leg, on the floor you’re on now. Roll a bit to your little toe accompanied by a little hip angulation, then reverse and do a powerful side lunge. Now, do it just standing on the flat of your feet. Side lunge. Less quick, less powerful. Now watch speed skaters roll from little toe to big toe.

And, with respect to throwing oneself downhill, or falling, I get a very different sensation from each type of side-lunge. The former, I feel in control. The latter, I feel much more like I’m falling.

 

[karlo]

Right. But my gut tells me that while it is one thing to do it on the bike, it is quite different to be the bike.

I think you’re right.

 

[Unpiste]

A mental model is a huge plus. And, that model can change as one advances. Whatever the model is, it’s something by which we can affirm our understanding at the time. It’s when we see or experience something that deviates from the model that we have another opportunity to learn.

It’s more than that, though. A good mental model can allow you to work through a motion you’ve literally never tried before attempting it on skis.

This is not the same as muscle memory or reflexes, which are a different sort of unconscious mental model. One is about consciously planning ahead (short and long term), and the other is about unconsciously reacting to what’s actually happening in the moment.

 

[karlo]

There are points I agree with, and there are points I fail to reconcile.

Application of a force over distance transfers ("absorbs") energy.

Ok. Or, consumes energy?

Application of a force to an object that does not move (hardpack on a mountain) does not transfer kinetic energy from the skier, but it does change the skier's velocity.

I assume be “skier’s velocity” you mean the COM’s velocity. If that is correct, I am referring to a skier whose COM is going literally straight down, with skis carving turns on either side. There is no change of “skier’s velocity”, no change of COM velocity, velocity being speed and direction. The comparison I make is between a skier that makes no turns and straightlines and a skier that makes perfectly carved turns, ones that do not result in COM alternatively going at higher and lower speed (still in only one direction, down). In my mind, the skier making turns is allocating or diverting or consuming kinetic energy to facilitate the skis turning. Without forward motion (energy) the skis can’t turn

One way to think about this is a ball connected to a peg with a string (so that it's able to rotate freely around that peg). Give it a spin, and absent friction, it will keep moving forever even though its velocity is constantly changing. (If the highlighted quote were correct, the ball would stop after traveling 90° around the peg.) Satellites in orbit are another example.

I see that. However, the visual model I have, even if not correct from a physics pint of view, is that of an electric vehicle’s regenerative braking system. A flywheel, I think, slows the car down while turning a generator to charge a battery. When we ski, we turn skis instead of a flywheel, thereby transfer energy and reduce our COM’s speed. Where this analogy breaks down is energy from a flywheel gets stored in a battery. There is conservation of energy, though some is “lost” to heat. In skiing, I don’t know where the energy derived from slowing the COM (slowing the car) goes. I think that’s where you’re saying my model breaks down. But, setting real physics aside, the model does give me something that fits a lot of observations. More rapid turns, having same completeness, slow me down more. More complete turns, requiring more turning (acceleration of ski’s) slow me down more.

It is true that in this case, the portion of your velocity moving towards your suddenly-engaged edges must, in that moment, go somewhere. (Just like the ball isn't going to travel through the wall.) On skis, you're going to lose a lot of it to a combination of sliding (if you don't actually get the edges set immediately) and absorption within your body.

In my model, COM does not go towards edges. COM goes downhill. Skis, when turning, go toward COM in a carved turn. No sliding.

In a perfect carve, you're always moving in the direction your skis are pointing. The force you feel is the force required to change your velocity, but, from the reference frame of the "immovable" Earth (which is the frame from which we're measuring speed), your kinetic energy does not change due to the turn itself.

In a perfect carve, I feel I am always moving downhill, not in the direction my skis are pointing, except at the belly of each turn, where the skis are pointed downhill

 

[Ski&ride]

you pass the ball a head of the player and the player has to catch up to it

Move the body down the hill, the skis will catch up and end up underneath the body.

I struggle with doing drills on “easy” terrain, because I can’t “feel” the difference when I do it “right” vs doing it wrong. So I may be “doing it” but I’m not actually doing it to any benefit.

But take the drill to something steeper, I can FEEL the difference and I can adjust to find the “sweet spot”.

I like bump fields. There’s “steep” and “flat” right there on a single bump! Needs to be easy bumps though, like blue bumps for drills.

 

[karlo]

Move the body down the hill, the skis will catch up and end up underneath the body.

“Underneath”

So, that’s an interesting point and I assume you mean downhill of the body. At that point, we need to allow our bodies to catch up. In order to get on top of the skis, at which point the skis and feet are, literally, underneath. So, perhaps that’s another concept to discuss with students, what “underneath” means on a slope.

 

[LiquidFeet]

I like using "back up underneath" and "back up behind"
...feeling the skis grip the snow "back up behind" the body at the start of a turn
...bringing the skis "back up underneath" the body after the fall line
...skis move in a "sideways figure eight" under the body

 

[martyg]

I explain to students that you have to lose control to gain control. I have a diagram that is drawn in the snow to explain. We also do a drill, skis off, about the mechanics of how your body naturally turns when walking, and we then take those two concepts to skis. That concept of how you turn when you walk, ride a horse, turn a mtn bike on a tight switchback (and there are probably many others) - all apply to skiing. The biomenchanics don't change. Students can relate to that.

 

[Unpiste]

Ok. Or, consumes energy?

Application of a force over distance transfers ("absorbs") energy.

Consumes from the skier's perspective, but transfers overall. Energy is neither created nor destroyed (at least for any physics applicable to human scales).

I assume be “skier’s velocity” you mean the COM’s velocity. If that is correct, I am referring to a skier whose COM is going literally straight down, with skis carving turns on either side. There is no change of “skier’s velocity”, no change of COM velocity, velocity being speed and direction. The comparison I make is between a skier that makes no turns and straightlines and a skier that makes perfectly carved turns, ones that do not result in COM alternatively going at higher and lower speed (still in only one direction, down). In my mind, the skier making turns is allocating or diverting or consuming kinetic energy to facilitate the skis turning. Without forward motion (energy) the skis can’t turn

Application of a force to an object that does not move (hardpack on a mountain) does not transfer kinetic energy from the skier, but it does change the skier's velocity.

One can go straight down without turning the skis (go faster and faster straight down). Or, one can go down while turning the skis. Turning the skis changes their velocity (direction). Change in velocity is acceleration (we can feel the sideways acceleration when we turn our cars around a corner). Accelerating requires force. Application of the force absorbs energy, specifically the portion of kinetic energy that is going towards downwards velocity of the COM.

Here you seem to be describing a situation where the skier's COM is accelerating.

The situation you're describing does not really exist. If you're in the apex of a turn, but not feeling lateral acceleration due to the carve, then you're about half a second away from sitting on the ground.

However, if it were possible to carve without any lateral acceleration to the COM, the same situation I described for the skier just applies to the skis. Changing a ski's direction does not inherently remove kinetic energy from the ski. And, now the skier is being accelerated due to gravity alone and slowed only by frictional forces. The only reason this skier will ever slow down is by going uphill (or, more accurately, exceeding terminal velocity given the slope angle).

I see that. However, the visual model I have, even if not correct from a physics pint of view, is that of an electric vehicle’s regenerative braking system. A flywheel, I think, slows the car down while turning a generator to charge a battery. When we ski, we turn skis instead of a flywheel, thereby transfer energy and reduce our COM’s speed. Where this analogy breaks down is energy from a flywheel gets stored in a battery. There is conservation of energy, though some is “lost” to heat. In skiing, I don’t know where the energy derived from slowing the COM (slowing the car) goes. I think that’s where you’re saying my model breaks down. But, setting real physics aside, the model does give me something that fits a lot of observations. More rapid turns, having same completeness, slow me down more. More complete turns, requiring more turning (acceleration of ski’s) slow me down more.

One way to think about this is a ball connected to a peg with a string (so that it's able to rotate freely around that peg). Give it a spin, and absent friction, it will keep moving forever even though its velocity is constantly changing. (If the highlighted quote were correct, the ball would stop after traveling 90° around the peg.) Satellites in orbit are another example.

This is entering entirely new territory from a physics standpoint. As you initiate a carve, you do convert some of your kinetic energy to both potential energy in your now-flexed skis and angular momentum. (Technically, I believe, you're actually giving kinetic energy to Earth in exchange for angular momentum at the start of the turn, and reversing the exchange at the end, but this is getting somewhat into the weeds.) A good skier will be able to release that energy as they leave the turn (if they choose to), thus taking it into the next turn rather than losing it.

However, we don't ski in an idealized physical model. Entering and exiting a turn and even simply being in a carve all result in losses to the environment more so than literally going straight down. It takes energy to make tracks in the snow, heat is produced as materials bend and flex, etc. Again, a better skier will be able to minimize, but not eliminate these losses.

 

[karlo]

f you're in the apex of a turn, but not feeling lateral acceleration due to the carve

By that, you mean COM being flung to the side as the ski rebounds?

if it were possible to carve without any lateral acceleration to the COM, the same situation I described for the skier just applies to the skis. Changing a ski's direction does not inherently remove kinetic energy from the ski. And, now the skier is being accelerated due to gravity alone and slowed only by frictional forces. The only reason this skier will ever slow down is by going uphill

So, with no losses, the ski rebounds from turn to turn, like a perpetual pendulum? And, the pendulum’s swing has no effect on gravity’s pull on the hinge (the COM), on the acceleration of the hinge and on its speed?

Then, what’s slowing us down when we make turns is that turns create more friction than going straight down?

 

[Seldomski]

You slow down by friction between the skis and the snow and from 'work' you do on the snow. Specifically, displacing snow at the surface, either scraping it from the top (skidding, smearing, etc) or compaction (powder).

 

[Unpiste]

By that, you mean COM being flung to the side as the ski rebounds?

I’m talking about the middle of the turn, when you’re balanced with your COM to the inside of your outside ski, which is supporting most of your weight. Without the lateral acceleration due to the turn itself, you’d just fall over.

So, with no losses, the ski rebounds from turn to turn, like a perpetual pendulum? And, the pendulum’s swing has no effect on gravity’s pull on the hinge (the COM), on the acceleration of the hinge and on its speed?

Then, what’s slowing us down when we make turns is that turns create more friction than going straight down?

Yes, with no losses, the ski would rebound indefinitely (though since gravity is required for the ski to hold an edge, in reality you’d be accelerating indefinitely).

The downward acceleration you feel from gravity is scaled by the cosine of the angle between the acceleration of gravity and the nearest axis on which you’re able to move freely. (Any force pulling you into the ground is directly countered by the pressure of the ground resisting compaction, effectively cancelling that component.) However, the change in speed (alternately, kinetic energy) you’ll experience after falling from one elevation to another will be the same regardless of the path you take to get to the new elevation, assuming no friction or other losses. (Most simply, this is just conservation of energy, but the math will lead to this result whatever path you take.)

What’s slowing you down as you make a turn is likely primarily sliding laterally across the snow surface, but it’s also all the things I mentioned before. The tighter the turn, the more acceleration you feel from the skis, which means more opportunities for losses with every interaction you have with the snow. A static skier sliding straight down hardpack really only has to deal with friction and air resistance.

 

[Seldomski]

That got me thinking. How can the function of a good turn be explained, off ski’s, in order to get buy-in from a new skier or a skier that is having trouble advancing, so that the idea of “throwing ourselves downhill” is no longer “stupid”?

One other analogy from American ninja warrior. The quintuple steps. It is the first obstacle in almost every competition.


Watch the different approaches. Some jump to a step, stop, turn around methodically, then jump to the next, then repeat. Then there's the guys that just bound through, placing just one foot on each platform. The guys bounding are 'throwing themselves downhill.' They are dynamically balanced. If they stopped bounding, they would fall. Whereas the more measured approach is statically stable. Per @Josh Matta , those with the more conservative tactic are 'blocked.' It takes a leap of faith to bound from step to step, but leads to more efficient skiing and ability to handle more difficult terrain with ease.

Either approach works. Your blocked skier can get down the hill just fine, it just takes longer and is less efficient. Strive to become dynamically balanced.

 

[LiquidFeet]

....Your blocked skier can get down the hill just fine, it just takes longer and is less efficient. Strive to become dynamically balanced.

^^ Nice metaphor. Or simile. Or analogy. Whatever.
Nice.

 

[karlo]

One other analogy from American ninja warrior

If I could, I would have voted Like early and often.