Flexing through transition (video)

[Don Duran]

This subject gets misrepresented all too often. The crossing of the two paths Core (CoM) and the feet is pretty simple. The core seeks to go straight (Newtons 1st &3rd) and the feet while also being subject to these laws they additionally must follow Eulers laws. (Movement relative to rhe CoM).

In short it means the feet and skis are being accelerated laterally by snow reaction forces. So even though when seen from above it appears their seperate paths intersect when seen in 3d they do not. So which passes over, or under? Both since both are in motion. Even in releasing the core (reducing ski snow pressure by flexing the legs) it is actions the legs, feet, and skis that changes the path of both the feet and core.
Nor is rhis limited to up/down unweighting. That would infer a vertical release move as the only option. Rolling releases (untipping the skis until they lose edge purchase) would thus not be part of that model.
To me the debate over cross/over/under is a bit silly because both always occur in spite of a mental focus. Hope this makes sense...
Enjoy.
Don

 

[BornToSki683]

As I see it, tipping the ski and flexing are the the main controls, the prime movers if you will, but I prefer to think of CoM moving across the skis' path AND skis moving across the CoM's path, CoM dropping to base of support AND BoS moving up to the CoM, Tipping AND flexing. I prefer to free my mind from the constraints of only one reference system.

Agree with you and I like this definition as it focuses on the cross under measuring the intensity that the skis cross under the CoM from side to side, perpendicular to the direction of travel of the CoM, while your cross over definition focuses on the intensity that the CoM continues moving in a straight ish line rather then being stalled, crossing over the path the skis are taking. And as you said earlier in various ways, that essentially means all decent ski turns have both things happening, they are not mutually exclusive. These two concepts are the two things that I think people have conflated a lot over the years, mis labeling turns as one type or the other.

They are different concepts, not mutually exclusive. Crossover is a measurement of releasing through transition and cross under is a measurement of impulse coming from the edged skis at the apex.

By this definition I guess all turns have cross under always happening, except for maybe pivot slips which are absent of both cross under and cross over. But in real ski turns the skis always cross under. Some turns do it with more energy.

Cross over however is another story, I think if you stall the CoM’s forward progress with a blocking pole plant, for example, even as the skis are starting to cross under, then you will get almost entirely cross under without any cross over( and a lot of pivot). It doesn’t require a blocking pole plant to stall the CoM, just merely avoiding a full “release” of the CoM from the old turn will stall it or slow it down enough to greatly diminish the CoM’s crossover through transition.

I hope some can see then, that flexing to release contributes to cross over! Not cross under! So called retraction turns can and should be enhancing cross over!

Cross under is enhanced or made more intense or rapid, by a stronger impulse at the apex and perhaps by releasing the edges later. Also stalling out the CoM with a blocking pole plant or deficient release could contribute to a turn seeming to be more cross underish since it will be devoid of cross over during transition.

Now all that being said, when I see peers trying to emulate so called retraction turns, they often struggle with it because whether they want to admit it or not they don’t know how to release their CoM with flexion of the downhill leg. They are trying to imitate the look of a retraction turn but they still aren’t releasing with flexion through transition. So they will tend to try to exaggerate the impulse at the apex in order to get a stronger cross under, so that as the skis will zing across the hill, even with hardly any release and cross over of the CoM through transition. So they achieve one type of retraction turn that way which usually has a pivot involved due to the fact the CoM didn’t release and crossover well.

What I have been trying to say is that flex to release turns do not have to be this way. If you actually release when you flex, then the CoM will crossover. if you want a high performance carving turn, you do want and need the CoM to crossover.

When we observe these transitions with flexion look closely to see if the skis are pivoting. If they aren’t, then the CoM is crossing over and probably the flex to release is effective. The amount of cross under zip you see will be a factor of the impulse from the edged skis at the apex or just after, or late releasing of the skis.

 

[BornToSki683]

Reflecting a little further on this matter, including some of the stuff from Doby earlier...

Crossunder/over is only concerned with the lateral displacement of each other.

"retraction" to me is a description of the vertical disposition between the CoM and BoS that is not necessarily reliant on their lateral disposition.

I do agree with you that flex to release isn’t necessarily going to constitute a crossunder turn. I don’t use flex to release but,..

...Regardless of that, with the right skills and mobility, we aren’t even “releasing” our CoM in “short’ turns at all.

Just like an expert zipper line mogul skier whose CoM rides straight down the fall line with almost no lateral displacement to speak of. For an advanced short turn skier, releasing the CoM for a “flex to release” move doesn’t even happen.

Ok, so its possible that the word release here is not being used consistently. I don't really care about identifying some particular "correct" use of the word...as far as I'm concerned, if you can get your point across then it works. We often see confusion in these discussions, for example, when using the word "release" and not clarifying if its the skis or the CoM that is being released. Two different things. They are both a type of "release".

Here I can see yet a new releasing distinction that perhaps needs to be made...

I see here two different CoM release concepts being slightly conflated in the discussion. One is the concept of releasing the CoM through transition to allow it to move/flow across the skis in crossover. It facilities continuation of movement. That's the concept that I personally I am usually talking about.

But the kind of release that I think Doby is describing here is a bit different, he's talking about actually stopping the movement of the CoM side to side across the hill by releasing the impulse energy harvested at the apex with deep flexing of both legs, which halts the CoM's lateral movement and allows the skis to zip across without having to push the CoM there.

Two different things really, though both do involve flexing or relaxing the legs, with subtly different timing in terms of muscle relaxation in two different legs at different parts of the turn.

Regarding the super short radius turns you identified, where the upper body appears to come straight down the fall line without displacing side to side across the hill: In this type of turn, the skier is releasing the impulse energy before it moves the upper body across the hill, instead that energy zips the skis across. Absolutely. When we see what looks like high energy cross under, there is a lot of that happening. However, it still may or may not mean the skier is flexing to release their CoM with the other kind of release, which is to allow the CoM to move and flow down the fall line and crossover the skis. If they don't release their CoM to crossover, then they will have a lot of pivot. If they want higher performance they will also release their CoM to move, flow down the hill into the next turn, which will enable a more carve-pure turn entry and rounder SRT turn shape. Both types of releases absolutely can be done in the same turn!

The subtle difference is the timing and muscle relaxation used in each leg. WHEN you release the forces and how you do that between your two legs in different amounts at different times. Relaxing and flexing to release the old outside leg at a certain timing in the turn allows the CoM to move/flow across the skis into the inside of the next turn. The old inside leg is typically already flexed. Allowing it to flex even more does not contribute to this crossover, but it could contribute to halting side to side displacement of the CoM, allowing the skis to zip across in crossunder instead. Also relaxing the outside leg late can contribute to harnessing more of the impulse energy from the apex, and it also slows down or halts the transition crossover of the CoM.

So these factors all contribute to some interesting combinations of things that can happen when you use flexion to release, depending on the timing between inside and outside leg and where in the turn it happens.

What I typically see with peers attempting to do so called "retraction turns" as something they don't normally do, they will relax the old outside leg late (harnessing as much apex impulse as they can, but also reducing or eliminating crossover movement of the CoM, and then they will retract both legs deeply, having lost their crossover movement...the skis do cross under, and will almost certainly pivot because they lost crossover movement. It doesn't have to be the way though, its possible to get just the right amount of cross under without losing crossover.

Typically in SL they are WANTING to displace the CoM sideways across the hill, and I would claim this is the harder skill in SL sized turns. That means they need to harness the impulse energy from the apex to not necessarily cross under so much, they need the skis to push their CoM across the hill also. Why then are they flexing so deeply through transition in many cases? Lots of times they are just trying to get to the new edges ASAP. The shortest path for the CoM can take means shortening the legs, but they are also being careful not to actually release too much of that apex impulse energy..they want it to displace them across.

Again watch these videos from TDK closely... From this Camara angle is really hard to see the crossover because that movement happens towards the Camara. A side view would show it more. But you can still figure out whether its happening by looking at how the skis are tracking. If the skier gets to the new edges without a pivot, then crossover is happening and that means they flexed to release (in the sense of allowing CoM to move/flow across the skis)... And we really have no idea when each of their leg muscles is actually relaxing, we can only draw conclusions of what we think they are doing based on the outcomes if we know what to look for. To some extent you can watch each leg very carefully to see which one is in the act of flexing or extending at any given moment of time and make some determination about how and when they are relaxing their muscles in each leg to allow things to happen.

Bottom line, flex to release does not necessarily mean its categorically a "cross under" turn. I think many people that are stuck on that notion will tend to miss opportunities to explore what is possible through downhill leg relaxation and release to cause movement of the CoM to crossover.

 

[razie]

Wow - what complication. I could not follow this thread in detail even as I tried...

For me, cross-under and over never made sense, because the body always crosses over the skis and the skis always cross under the body and I continue to refrain from using these expressions as much as possible, since I don't see the phrases themselves to add any semantic value

Instead of looking at what we do when the skis are flat (i.e. crossings), the relevant part is how you release. Do you:
a) push or even extend and hop off the old set of edges?
b) relax and flex the long outside leg and release the edge that way?

So: push-to-release vs flex-to-release.

Easy enough?

p.s. Other release types like the COM release are smaller variants we can ignore until a tactics discussion.

In fact, within the flexed release family there are 5 sub-categories, if you're interested in a different discussion.

 

[BornToSki683]

you of all people, I know can follow it if you try..

 

[Fishbowl]

In fact, within the flexed release family there are 5 sub-categories, if you're interested in a more interesting discussion.

I would be interested in learning about different types of flexed releases. Another thread?

 

[razie]

you of all people, I know can follow it...

Well, if you put it that way...



Really though - I see the points, but instead of dissecting it like this, really, I prefer to just roll back to the release and focus on that? Everything is set in motion at and by the release - that's the important bit.

When the skis are flat, they can be pivoted, in fact much too easily, but the more skilled option, as pointed out already, is to not pivot them and keep a clean transition.

p.s. BTS - good to see you posting.

 

[BornToSki683]

well this discussion just flowed this way...and digging deeper. You don't have to read and dig if you don't want to.

What are your 5 release types?

 

[razie]

Here's just the quick list of the variants allowed when flexing the long outside leg, IMHO:
- floated or relaxed (i.e. relax and flex)
- retraction (i.e. extreme)
- early transfer (as in early transfer of balance to the old inside ski) - careful to not extend the old inside while on the wrong edges
- late or weighted (you may know the related white pass drill)
- COM release (release the COM by relaxing the upper legs, while keeping the skis engaged a little longer - just a different sequencing of the relaxation, sometimes used in GS/speed)

I can't get now into an in-depth or what I see as the tactics behind each... especially as at least one of them (if not two) may trigger some debate. Later maybe. But I think expert skiers and certainly racers are well advised to practice all - that's when they then have tactical options.

cheers

p.s. I guess @Fishbowl is right - creating a separate thread is better.

 

[BornToSki683]

Oh I dunno. TDK has provided some video here with a bunch of turns using flex to release in slightly different variations... why not here? Bring it back to the video

 

[mister moose]

OK, I'll play too.

It seems to me that cross over/cross under is very much a reference frame thing. But let's delve a little deeper and define some terms.

First can someone please tell me what BoS is? Obviously a synonym for feet.

Second, cross over vs cross under depends on which is moving, and which is moving is strictly a reference frame thing until you look at what moves relative to the hill. The point in time we want to look at is the moment, when viewed from face on to the direction of motion of the skier, the feet and CoM are in vertical alignment.

Cross under means to me the feet are moving across the hill, not the CoM. Moving means accelerating, moving in a different direction than the overall path of motion. (definition of terms, acceleration is a change in velocity or direction) Cross under means the skis do not follow the path of the CoM, and at the moment of crossing there are no lateral forces felt by the skier. The feet are crossing, and are not applying force to move the CoM laterally. There is no lateral acceleration of the skier or the CoM at that moment.

Cross over means to me that the upper body is doing the crossing, not the feet. For this to occur, the CoM moves laterally, (relative to the direction of motion) not the feet. The feet now have to be engaged in order for forces to be applied to accelerate the CoM. The feet are now applying force to accelerate the CoM across the path, ie skier's left to skier's right.

So. Lateral forces on the CoM only exist when the CoM is accelerated laterally.

Cross under means at the moment of vertical alignment in the turn feet are light and not edged. CoM is not being accelerated laterally at that moment in time, the feet are.
Cross over means at the moment of vertical alignment in the turn at least one ski is edged and applying lateral pressure, and is not light. The CoM is being accelerated laterally at that moment in time, the feet are not.


Or I quite possibly have no idea what I'm talking about.

 

[François Pugh]

OK, I'll play too.

It seems to me that cross over/cross under is very much a reference frame thing. But lets delve a little deeper and define some terms.

First can someone please tell me what BoS is? Obviously a synonym for feet.

Second, cross over vs cross under depends on which is moving, and which is moving is strictly a reference frame thing until you look at what moves relative to the hill. The point in time we want to look at is the moment, when viewed from face on to the direction of motion of the skier, the feet and CoM are in vertical alignment.

Cross under means to me the feet are moving across the hill, not the CoM. Moving means accelerating, moving in a different direction than the overall path of motion. (definition of terms, acceleration is a change in velocity or direction) Cross under means the skis do not follow the path of the CoM, and at the moment of crossing there are no lateral forces felt by the skier. The feet are crossing, and are not applying force to move the CoM laterally. There is no lateral acceleration of the skier or the CoM at that moment.

Cross over means to me that the upper body is doing the crossing, not the feet. For this to occur, the CoM moves laterally, (relative to the direction of motion) not the feet. The feet now have to be engaged in order for forces to be applied to accelerate the CoM. The feet are now applying force to accelerate the CoM across the path, ie skier's left to skier's right.

So.

Cross under means at the moment of vertical alignment in the turn feet are light and not edged. CoM is not being accelerated laterally at that moment in time, the feet are.
Cross over means at the moment of vertical alignment in the turn at least one ski is edged and applying lateral pressure, and is not light. The CoM is being accelerated laterally at that moment in time, the feet are not.


Or I quite possibly have no idea what I'm talking about.

BoS means base of support.

 

[Don Duran]

I'm with Razie in this debate, the coincidental dual paths occurs in all turns. Frames of reference do not change any of that BTW. The body moves through space, as do the feet. Relative to each other they are also continuously moving. It is a significant point and not open to debate. Changing the relationship between the core and the feet to affects how the skis interact with the snow is the key. Which moves more leads to the labels (x-under /over / through) but the literalists fail miserably when they suggest their labels are more than a mental construct meant to describe what moved more. The spectrum of possibilities don't need labeling but for some it helps them make more sense of those possibilities. This is fine as long as we avoid trying to turn those labels into distinctly different maneuvers.

 

[BornToSki683]

Sorry is there a debate? I think we’ve all pretty much said the same or similar things with different levels of detail in our own way about cross over or cross under, sharing some different ideas about it. What is your and razie’s beef that I’m missing now?

 

[razie]

No beef - I just don't like to use cross-under/over.

The WC dude (initially I thought it was TDK having too much fun and I was thinking damn, I gotta start masters training again ) is doing flexed releases with early transfer, in all the turns in the OP video - which is quite common for the good skiers on the WC. Not that much of a retraction, although one turn he pinches a gate or something and had to be more forceful. Good skiing although there's something going on on one side, imo.

What's the money shot? If I were to take one frame to show how I can tell (rightfully or mistakenly), which frame is it and what would I be looking at in it?

 

[LiquidFeet]

My skis cross my path because they are tipped onto their inside edges and the snow makes them turn, and as they cross under the path of my CofM, which has been released, they get tipped onto their new edges, due to my CofM being connected to them through my legs which become downhill from them.

This post bears repeating. I didn't notice anyone responding to it directly upthread. Handling transitions this way doesn't get enough attention.

It sounds like François Pugh works his skis in such a way that, after they go through the fall line/apex, he brings them back up under him (with continued edging, not flat ski rotating). This completes the turn. He brings the skis back up under him so far that his feet end up uphill of his CoM. This is the central point of his post.

In my skiing, I think of this as "over-completing" my turns. For anyone reading here who has never done this, it's worth a try. The first time someone feels the skis come all the way up under the body, crossing under its path, there's quite a surprise. The feeling is an eye-opener. Wheee!

A skier ending and starting turns this way does not directly do anything to cause the upper body/CoM to cross over the skis. That's an indirect result of the path of the skis relative to the path of the upper body. The skis' path is the skier's focus. The skier allows the upper body to keep moving along its own path while all the work is being done down below with the feet/legs/skis.

Once the feet move behind/uphill of the CoM, the skier is "upside down" on the hill. The skis naturally tip onto new edges because of the inclination of the legs. The skier doesn't have to do anything more to tip skis onto new edges; it's already been done. The top of the new turn is happening.

The legs get short when the skier brings the tipped skis back up under the body. So this is a flexed transition.

François Pugh, let me know if this matches what you meant.

 

[Kneale Brownson]

Third, fifth, seventh, etc. turns in the video show "upside down" situations.

 

[François Pugh]

This post bears repeating. I didn't notice anyone responding to it directly upthread. Handling transitions this way doesn't get enough attention.

It sounds like François Pugh works his skis in such a way that, after they go through the fall line/apex, he brings them back up under him (with continued edging, not flat ski rotating). This completes the turn. He brings the skis back up under him so far that his feet end up uphill of his CoM. This is the central point of his post.

In my skiing, I think of this as "over-completing" my turns. For anyone reading here who has never done this, it's worth a try. The first time someone feels the skis come all the way up under the body, crossing under its path, there's quite a surprise. The feeling is an eye-opener. Wheee!

A skier ending and starting turns this way does not directly do anything to cause the upper body/CoM to cross over the skis. That's an indirect result of the path of the skis relative to the path of the upper body. The skis' path is the skier's focus. The skier allows the upper body to keep moving along its own path while all the work is being done down below with the feet/legs/skis.

Once the feet move behind/uphill of the CoM, the skier is "upside down" on the hill. The skis naturally tip onto new edges because of the inclination of the legs. The skier doesn't have to do anything more to tip skis onto new edges; it's already been done. The top of the new turn is happening.

The legs get short when the skier brings the tipped skis back up under the body. So this is a flexed transition.

François Pugh, let me know if this matches what you meant.

Your description is pretty close. It is currently one of my favorite ways to transition from one turn to the other. It is what I meant when I used the term cross-under (not implying any pivoting of skis). There are variations of course. It's all about the release of the CoM from its curved trajectory. I play with how soon I begin the CoM release by flexing the outside leg, how suddenly I release it and how much I continue to keep the skis on edge and turning.

 

[BornToSki683]

This post bears repeating. I didn't notice anyone responding to it directly upthread. Handling transitions this way doesn't get enough attention.

It sounds like François Pugh works his skis in such a way that, after they go through the fall line/apex, he brings them back up under him (with continued edging, not flat ski rotating). This completes the turn. He brings the skis back up under him so far that his feet end up uphill of his CoM. This is the central point of his post.

In my skiing, I think of this as "over-completing" my turns. For anyone reading here who has never done this, it's worth a try. The first time someone feels the skis come all the way up under the body, crossing under its path, there's quite a surprise. The feeling is an eye-opener. Wheee!

A skier ending and starting turns this way does not directly do anything to cause the upper body/CoM to cross over the skis. That's an indirect result of the path of the skis relative to the path of the upper body. The skis' path is the skier's focus. The skier allows the upper body to keep moving along its own path while all the work is being done down below with the feet/legs/skis.

Once the feet move behind/uphill of the CoM, the skier is "upside down" on the hill. The skis naturally tip onto new edges because of the inclination of the legs. The skier doesn't have to do anything more to tip skis onto new edges; it's already been done. The top of the new turn is happening.

The legs get short when the skier brings the tipped skis back up under the body. So this is a flexed transition.

François Pugh, let me know if this matches what you meant.

Isn’t that the good ol’ infinity move?

For those people not offended by the terms I guess that is kind of a focus on the cross under aspect. Except the part about allowing the upper body to continue to move straightish.

You mentioned some unspecified work being done by the lower body to accomplish the fact that the upper body is allowed to continue traveling during along its straightish path while the feet make the figure eight.

Care to elaborate on specifically what movements the lower legs need to do in order to accomplish this? Particularly with regards to flexion during transition with regards to this thread.

 

[LiquidFeet]

Isn’t that the good ol’ infinity move? .....
Care to elaborate on specifically what movements the lower legs need to do in order to accomplish this? Particularly with regards to flexion during transition with regards to this thread.

Yes, this is Bob Barnes' "Infinity Move." This move is also thought of as the feet going in a "sideways figure eight" beneath the upper body.

Specific movements:
1. After the fall line, continue tipping the inside ski to higher angles progressively (use ankle tipping; the knee will continue to roll in). That ski will continue to turn around and uphill, pushed by the snow along its curved path, as FP noted.
2. Along with that tipping, pull up (shorten) the inside leg so that ski is drawn back up under you.
3. The outside ski follows along like a dog on a leash, usually. It continues to tip more, just as the inside ski does. That leg shortens as well as it approaches the body.
4. Re: both legs/feet/skis are coming back up under you, each of them getting onto higher edges and each leg getting shorter to accomplish this. You'll be low in transition.
5. Mental goal: get the feet up underneath and uphill of your upper body.
6. As the feet move up under the CoM/upper body, the body will continue forward down the hill on its already established trajectory.
7. The whole body, moving as a unit with legs attached, progressively pulls the skis to flat.
8. That pull tips the skis onto new edges. All of this happens very fast. The flip to new edges feels dramatic. It's like riding a roller coaster just as it crests the summit and starts downhill.
8. The skier will be "upside down" on the hill, with the top of the turn about to happen. There will be no "drifting" on flattish edges.

Is that what you were looking for?