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TS
Have you tried speeding them up? 1.5x and 1.75x work for me.
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Completing your turns
- Thread starter LiquidFeet
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I was watching the Steep and Deep video linked in this thread https://www.pugski.com/threads/jackson-hole-steep-and-deep-camp.18588/post-521256
and trying to figure out why the instructors looked so different from their students (in most of the groups, at least).
Sure one difference is a "quiet" upper body. But another is that the students are finishing the heck out of their turns, while the instructors are moving on to the next turn without wringing all the life out of the current turn.
and trying to figure out why the instructors looked so different from their students (in most of the groups, at least).
Sure one difference is a "quiet" upper body. But another is that the students are finishing the heck out of their turns, while the instructors are moving on to the next turn without wringing all the life out of the current turn.
It's a long vid and there's a wide range of turns on display. So may not be the same skiing that you are commenting on however I see people not so much hanging on to the turn too long as hanging in the zone between turns too long. The sideslip equivalent of traversing. It's like making a series of 1st turns rather than flowing. Tend to view that as a consequence of not finishing the last turn fully and therefore not being "balanced", ready to start the new.
Admission here -- after I watched that video, I watched my copy of the analogous video from my last S&D in 2012. There was (a lot) more fresh snow in that one, and the getting stuck in the last turn was more evident there (including by me). But once I was primed to look for it, I saw some of it in this video too.
Maybe the difference is the snow.... in soft snow, when you hold on too long you wind up digging in, while in hard snow it turns into a skid.
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From my race coaching perspective, there are two big reasons why I would advocate for turn completion. I like to think the most obvious is maintenance of the line. Completing a turn sets you up, assuming you have a tactically sound line to begin with, well for the next gate and maintains the rhythm through the course - not always applicable obviously, as hairpins and delays can change up the rhythm/direction of the course thus necessitating letting your outside ski go earlier than what would be considered the end of the turn.
The other big reason is the take full advantage of the skis themselves. The ski is a big spring, and through the apex of a turn, assuming it is edging cleanly, it builds up a ton of energy. If it is released at the 'end' of the turn, the energy gets directed down the fall line, providing acceleration down course for the racer. If the racer releases the ski too early (ie before the end of the turn), the energy is generally wasted, or can even slow them. This is actually one of the more challenging things to teach, as with the rise of athleticism and technology, top level athletes generate significant edge angles through the apex of a turn. The 'cool' pictures are then taken of them in this very compressed body position, hip to the snow etc, that kids then try to replicate, unfortunately they do it in a reverse order, making getting the hip to the snow the goal, not clean edging and good pressure on the outside ski and released into the fall line. I remember reading another thread on here, and one of the posters posted a bunch of videos of him making these 'hip to the snow turns', which in reality was just him sitting into the turn and essentially releasing his outside ski/riding his inside ski, which is exactly one of the issues that I find we have to correct for with some of the younger keen kids that spend lots of time on youtube.
Finally, it is not always beneficial to gain maximum acceleration down the fall line, especially during a particularly steep section where speed control is important. Places where you'd use stivots to speed check or change the direction of the ski without locking the edge in through the turn. It's always a dance between generating speed and controlling it.
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Could you please draw some force diagrams of how this happens.
It's not that I'm skeptical it's that Jurij Franco and Ron le Master have written things that seem to indicate they are skeptical.
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I just ignored the spring part. It’s conceptual I suppose. Some years ago @razie did a somewhat comical video of decambering a race ski and trying to launch something like an empty helmet. Didn’t do much.
What he’s talking about I think at 0:44-
At 0:44...
Even if energy can be harnessed from the bent ski at best it's going to unload in the direction of the blue line leading from the gate. How does this propel the skier down the fall line?
If skis loaded in a turn can propel the skier in the forward direction does this mean we could cross a frozen lake by making S turns? That's a question Jurij Franco asked.
Yeah, it's not the ski - it's a common misconception: it contributes, but little. It's the energy from the impulse of the turn, virtual bump, body compression, counter, coiling etc. If you time it right, it feels like the same thing...
Wow - that's quite the stroll down that lane... good memory, James!
There was so much controversy at the time, I also made this one:
The thing was not having anything under the middle of the ski, where you normally have the ice/snow etc... but even so, a 3" bend is WC territory!
The other thing that came out of those tests, that I did not capture in the videos was that you can easily overpower the outside ski and eliminate that small pop with mistiming the release - even with a tiny mistiming, it was easy to kill any pop from the ski.
Wow - that's quite the stroll down that lane... good memory, James!
There was so much controversy at the time, I also made this one:
The thing was not having anything under the middle of the ski, where you normally have the ice/snow etc... but even so, a 3" bend is WC territory!
The other thing that came out of those tests, that I did not capture in the videos was that you can easily overpower the outside ski and eliminate that small pop with mistiming the release - even with a tiny mistiming, it was easy to kill any pop from the ski.
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There are many good comments here about student perceptions. A good reminder to me that what we say and how we say it matters.
Turn completion is part of control. Control is the same throughout all human endeavors. Control starts with intent of what you want to happen, then proceeds to decisions based on that intent and then to follow through on your decisions and finally to the intended outcome. The problem in skiing, is that lack of the control process does not mean things are okay. You are standing on a banana peel on a slippery slope and the banana peel and gravity will gladly make all the decisions for you that you did not make resulting in the usual unintended consequences.
Making decisions seems simple but the majority of skiers actually do not make decisions with intent. They make decisions based on avoidance and perceived safety. They believe they ski well when they get proficient at decisions of avoiding perceived bad options. Good teaching is about interactively guiding the process and setting parameters in any part of the process to affect an agreed upon outcome.
Turn completion is part of control. Control is the same throughout all human endeavors. Control starts with intent of what you want to happen, then proceeds to decisions based on that intent and then to follow through on your decisions and finally to the intended outcome. The problem in skiing, is that lack of the control process does not mean things are okay. You are standing on a banana peel on a slippery slope and the banana peel and gravity will gladly make all the decisions for you that you did not make resulting in the usual unintended consequences.
Making decisions seems simple but the majority of skiers actually do not make decisions with intent. They make decisions based on avoidance and perceived safety. They believe they ski well when they get proficient at decisions of avoiding perceived bad options. Good teaching is about interactively guiding the process and setting parameters in any part of the process to affect an agreed upon outcome.
I actually do know what he is talking about here. SlapChop is correct about the acceleration and the timing and direction but mostly incorrect about the mechanism.
The energy for all of this is not ski compression or coiled energy. The energy for all of this is momentum. That momentum is most useful if its direction intersects on a line above the next turn apex. That is why you don't release too soon. Releasing too soon directs you momentum below the next turn apex. Momentum is energy that can then be used to load the outside ski well before the fall line and take advantage of angular acceleration, combined with gravity for explosive acceleration through the apex/fall line. I think that is what SlapChop is getting at.
It more or less is the virtual bump but I like to call it "The Swing Set Effect". Ever wonder how a swing set can work without external force? Visually a swing set does not make any sense at all.
SlapChop is correct that is requires very clean arcs but arcs that are under the turn radius of the ski. If you release too early you simply give up your momentum in a direction where it cannot be used and in fact you fight it.
If I get to pick the terrain in a ski challenge I am going to pick terrain in one of two places. The first terrain I would choose is steep bumps made of solid coral snow but that is for another post using swing set in reverse. The second venue I will pick is a long nearly dead flat groomer. Within three or four turns I am in full swing set mode and high edge angles. Mastery of the swing set effect is rare enough that I am likely to win even if the other skier is good. There is no other method that will accelerate you that someone can bring to the table. I'm going to pull away from any challenger like I have rockets on the back of my skis. My turns will be short, clean and well finished. I believe an athletic skier whom has mastered the swing set effect can come off of a slope onto a frozen lake and sustain their skiing using S turns with full use of the swing set effect for some distance. The cleaner their skiing the further they will go. I can even sustain it for a bit uphill but I tire quickly. Good skiers will get in my face over skiing on flat terrain far more often than any other skiing that I do. If the technique is done very cleanly, the gas pedal is not visible.
Incidentally SlapChop, flat terrain is where you go to make the little buggers learn it. They are denied every other method to accelerate. the cleaner they ski it, the faster they will go. Skating as a means it much slower. The feedback is in your face on flat terrain.
Really nifty video MDF. Thanks for sharing it.
There are two ways to control your speed on skis: Move snow (Lose energy to snow by deforming it) or go up the hill (store energy from kinetic back to potential).
The instructors in that video are almost universally using *where* they go to control their speed, They maintain edge grip until/through the edge change, so the skis/CoM are always traveling generally in the direction the ski is pointed (the skis are roughly aligned with the direction of the momentum vector).
The students push snow to slow down way more often, especially as the terrain gets steeper. I can verify that by seeing when their Skis are pointed in a different direction than their CoM is traveling (aka skis pointed sideways, skier going down).
I see the maintenance of grip through transition and alignment of momentum with ski direction as the inputs required for "finishing the turn" (and really, turning period). My belief: The better the skier is, the more likely they are to always be changing the direction of their momentum, not just the direction of their skis.
With regard to "how do snow conditions change things?".
I find unconsolidated snow punishes not aligning the direction of the skis with the direction of travel more, because there's a much bigger cross section of ski traveling through snow. (What's easier to side-slip through: 6 inches of mank or a groomer?) Whether the skis grip or slip in any condition is a question of the angle of the skis to the CoM, not the snow condition (assuming the ski itself can penetrate the surface).
This is where understanding the difference between a "GO" intent and a "STOP" intent and how it affects ski performance. If we look at the skis interaction with the snow on a spectrum, a GO intent turn would be at one end of the spectrum where the skis are moving forward along the length of the ski at turn completion (ie: carving) at the other end of this spectrum would be the skis pivoted to a 90 degree angle to the direction of travel. The first extreme is skiing a slow enough line to control your speed yet skiing around that line as fast as you can. The other extreme is maximum braking with the skis pivoted across the direction of travel to BRAKE rather than go.
Understanding we can not ski back up the hill, completing a turn while more toward the carving end of the spectrum will show a rounder more across or even slightly uphill completion. Though this kind of turn is not possible in all situations, the intent or goal is to ski the roundest line possible with minimal steering angle as possible for the situation. If you are in a steep chute only slightly wider than the length of your skis, you are going to be closer to the pivot end of the edging vs. pivoting end of the spectrum.
So completing a turn could mean getting your skis across the fall line, However; How you arrive there can be very different. If your steering angle is 45 degrees to direction of travel or greater, you are braking more than turning. If your steering angle is less than 45 degrees to direction of travel you are turning more than braking. My goal/INTENT is to always be redirecting more than braking. Carving more than skidding given any situation.
Understanding we can not ski back up the hill, completing a turn while more toward the carving end of the spectrum will show a rounder more across or even slightly uphill completion. Though this kind of turn is not possible in all situations, the intent or goal is to ski the roundest line possible with minimal steering angle as possible for the situation. If you are in a steep chute only slightly wider than the length of your skis, you are going to be closer to the pivot end of the edging vs. pivoting end of the spectrum.
So completing a turn could mean getting your skis across the fall line, However; How you arrive there can be very different. If your steering angle is 45 degrees to direction of travel or greater, you are braking more than turning. If your steering angle is less than 45 degrees to direction of travel you are turning more than braking. My goal/INTENT is to always be redirecting more than braking. Carving more than skidding given any situation.
Good writings. Some very esoteric explanations and of course highly appropriate here especially with the above audience ands participants.
Go out on the slopes and explain finishing a turn to an intermediate skier. Lead him or her down the slopes finishing every turn. Maybe the skier right behind will get it, maybe not.
I don't teach anymore with the ski school but have taught my best friend and his two boys and my powder partners wife. So for what it is worth (not much I know) heres what I do. First, no esoteric explanations. Watch a skier having trouble and you will see J turns instead of rounded turns. The steeper the terrain the more this is obvious. Tell the student that we are going to finish our turns, draw the line in the snow to illustrate and explain the J turns make it increasingly harder to control our speed.
Have the student lead down the hill but they can't turn until you tell them, "turn". Then have them finish up hill, across the hill and vary the turns per their ability and the mountain.
This will lead to explanations on skiing the whole mountain and how to ski the terrain not defensively but with control, smarts and how to begin flowing down the mountain.
Go out on the slopes and explain finishing a turn to an intermediate skier. Lead him or her down the slopes finishing every turn. Maybe the skier right behind will get it, maybe not.
I don't teach anymore with the ski school but have taught my best friend and his two boys and my powder partners wife. So for what it is worth (not much I know) heres what I do. First, no esoteric explanations. Watch a skier having trouble and you will see J turns instead of rounded turns. The steeper the terrain the more this is obvious. Tell the student that we are going to finish our turns, draw the line in the snow to illustrate and explain the J turns make it increasingly harder to control our speed.
Have the student lead down the hill but they can't turn until you tell them, "turn". Then have them finish up hill, across the hill and vary the turns per their ability and the mountain.
This will lead to explanations on skiing the whole mountain and how to ski the terrain not defensively but with control, smarts and how to begin flowing down the mountain.
@Pierre, your description above doesn't comport with my understanding of physics. Physics defines momentum as mass times velocity. Mass is constant. Velocity is what you brought -- there isn't something in momentum that is imparting acceleration. So, if you are going to increase velocity, there has to be some other source of energy to impart it.
If you are able to propel yourself on the flat, it is because you are physically imparting energy into the system, not harvesting momentum.
In your swing set example, there IS an external source of energy -- it is the action of the swinger. Take that out of the system and the swing will slow and come to rest.
All that being said, using momentum to take energy out of the fall line through the virtual bump into the top of the next turn is part of what defines flow in expert skiing, IMHO.
Mike
Mike, I expected this comment at some point. I wrote this from a more pragmatic sense than a true physics sense. I have a dual degree in engineering so I do know what your problem with the explanation is. I quit fighting against incorrect common physics terms and now go with the flow. I use to go with all the correct physics terms in my posts and lost 90% of the readers. I went with the term of momentum because momentum is kind of a generic term so more peopel will have some idea of what you are talking about than if I use the strictest of physics terminology. In the true sense of the word, the driving force is always gravity with kinetic energy being the manifestation. Its the same for the swing set.
You are right about the dead flat lake being inputs entirely from the skier and that is why I tire very quickly but I can manage to go further than I can with a straight glide. Even a little bit of slope makes a huge difference. i am no match for gravity.
Been pondering the hows and whats of this "swing set effect" since this post. What is it? How does it work?
Now Jurij Franco * has posted a vid basically saying it's not really possible based on the inability of the body to add enough energy at racing speeds.
Note that Jurij does make a small mistake - he transcribes 100N from one calc into 1000N in another (he acknowledged that when I quizzed it) so there's even less possible energy to add than he shows on the board. In any event, as he points out, there's a problem adding even that small amount of energy to the CoM speed as the friction along the length of the ski is minimal so any rebound or propelling of mass by the skier is perpendicular to required direction.
Is there something Jurij is not considering in this?
* Jurij Franco is a physicist who who worked as a ski designer for Elan and is credited with working out the correct maths for the 1st shaped skis and the Elan SCX Parabolic ski. So he's not a FB Karen.
@geepers
Acceleration due to rebound or the ski working like a spring and all that sort of bladiebla is complete nonsense. Not how physics works, Jurij is missing nothing.
It's been a while since I read this, so I might be wrong. Cannot be bothered to check, but from what I remember they argued the perfect carving turn in ideal circunstances has a constant speed.
There is also paper I read where the better racers on average lost 0.31 km/h (or m/s, can't remember) below the fall line compared to above the fall line and the slightly worse racers were at like 0,7 km/h or m/s loss of speed.
Edging means resistance, it's not the gas pedal as some make it out to be.
Acceleration due to rebound or the ski working like a spring and all that sort of bladiebla is complete nonsense. Not how physics works, Jurij is missing nothing.
It's been a while since I read this, so I might be wrong. Cannot be bothered to check, but from what I remember they argued the perfect carving turn in ideal circunstances has a constant speed.
There is also paper I read where the better racers on average lost 0.31 km/h (or m/s, can't remember) below the fall line compared to above the fall line and the slightly worse racers were at like 0,7 km/h or m/s loss of speed.
Edging means resistance, it's not the gas pedal as some make it out to be.
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