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# Perception vs. Reality: Ski Tracks; What is really happening?

Perception vs. Reality: Ski Tracks

With the recent discussions that were occurring in the PMTS Race Camp thread that was started by Max_501 I thought it would be a good idea to investigate the differences in ski tracks. A few illustrations were presented in that thread, but I felt that they did not tell the whole story of what was going on in each situation. Since the discussion was originally based on what was done at the race camp I figured that rather than post in that thread and continue along its tangent I would begin a new thread to discuss the two ski track scenarios that were being discussed. Most everyone who read even a small amount of that thread by Max will remember that two distinct possibilities for track width were discussed: One being a varied track width, and the other being a constant track width. In order to understand both instances I have put together a few illustrations of each situation with the goal of explaining what is happening to each ski under different conditions of ski track width and change. All illustrations are assuming an arced/carved turn.

In order to “pick on” everyone you can see I have included instances of both varied track width and constant track width. Ignoring what teaching systems each diagram represents (meaning leave your allegiances at the door) I would like to start a discussion based on the information presented in the illustration, and hopefully shed some light on each situation for those who were reading the PMTS Race Camp thread as well as for those who were posting in that thread. Below I have included a diagram briefly explaining the difference between vertical and horizontal separation and its relation to the topic. Understanding the illustration below is essential to understanding the two track width scenarios since track width is heavily dependent on which “method” you are following.

Varied Track Width (Constant Horizontal Separation):

Varied track width is a result of using vertical separation in your ski turns versus focusing on horizontal separation. Remember, here we are not discussing prematurely or un-naturally pushing one ski or the other in any direction. It is simply using the same horizontal separation between your legs/shins at the apex of the turn as you would during the turn transition. Basically, if you were to draw a perpendicular line from one of your shins to the other shin while you were going straight down the mountain (not turning) and then you were to be able to measure that distance again at ANY POINT during ANY TURN you would find that it remains constant.

Interestingly, this type of turn is very well known for not using ANY ski redirection or pivoting to complete the turn. Most skiers who ski like this will swear up and down that no rotary movements are made when they are skiing. That is well, and it is very likely that they are not making any “intentional” redirection movements but based on the nature of the tracks re-directional movements do exist in the turn with varied track width. In reality this type of re-directional movement does not really matter, but there is no disputing its existence.

In the upper left corner of the illustration you can very easily see where the inside ski is pulled back at the top of the turn. In order to get divergent tracks at this point (as you tip/angulate at the top of the turn) this ski is pulled back and at the same time with the same movement the tip is pointed slightly toward the inside of the turn. Why does this not matter? Well the biggest reason is that new inside ski is not really weighted during this time, and without the exaggerated tracks that I have draw is virtually undetectable. Also, once the tiny redirection occurs the ski picks up on an arc much more similar to the arc that the outside ski is traveling on (unlike in the example in the upper right. Because the inside ski is traveling on a nearly identical arc, but traveling a shorter distance, the redirection is needed so that the ski will “pick up” the arc at the right point in the turn/transition.

Constant Track Width (Constant Vertical Separation):

When I was investigating this scenario I realized that there are a few possibilities for this type of track, and both are dependant on the position of the upper body. For argument’s sake lets assume that both skis are carving and you have your skis weighted in a 70/30 manner around the area of the apex of the turn. Let’s also assume that your body is following your skis and you are using minimal counter/counter rotation in your turn. This scenario will also give you minimal tip lead. [Essentially, a PSIA turn] If that is the case, the inside ski would have to be continually redirected for the entire turn simply because it would be skiing a tighter radius than the outside ski. If you wanted to properly carve that radius your weight would have to transfer to the inside ski in order to arc a tighter radius.

Even though your tracks’ vertical width stays constant throughout the turn the horizontal separation that you have actually gets smaller as the turn progresses toward the apex, and then grows as you progress toward the turn transition. If you are obtaining very big angles this requires a very wide stance in transition and will result in a very narrow stance near the apex. Interestingly, even though you are keeping parallel ski tracks all the time, you are constantly making very small rotary movements to keep your skis parallel and to keep the inside ski on a smaller radius. These movements grow to be quite big as you guide the inside ski through the turn, especially if your goal is little or no inside tip lead.

Conclusion:

What can we gather from all of this? Well without knowing what the center of mass (CM) is doing and how the skier is balanced through each scenario we cannot make a truly educated guess. I have actually prepared (in addition to these diagrams) several illustrations that do in fact show the path of the CM and the point of the CM on the snow at the apex of the turn (showing a crude sketch of skier body position). I would like to hear thoughts on these images before I present the rest of the images… and I will likely begin another thread for that discussion. I have however included a CM line for the “real world” scenario using constant horizontal separation to jump start the ideas.

Later

GREG

NOTE: Clicking on the images brings them up in a new window and then you will have the option to increase their size to 100%.
So, Greg, what's your thinking on these?

I like the diagrams and the differentiation that they represent. I find the redirection at the phantom move an interesting observation. Are there those who disagree?

Also, I find myself trying to think about which approach I use. How would I tell? What feelings would each of these illicit? Is one of them more likely to happen when I am "allowing" things to occur versus "making" things occur?
Greg
Haven't spent a lot of time on this yet but your definitions of horizontal and vertical separation are opposite of mine.
To me:
Horizontal separation is the amount of "daylight" between the legs.
Vertical separation is the distance apart the feet are, up and down, along the centerline between the legs. (like riding a bike with one pedal up and one down)(not much distance away from the centerline but quite aways apart vertically) At least that's how the coaches I know have been talking about it since 1984.
Quote:
 Originally Posted by SLATZ Greg Haven't spent a lot of time on this yet but your definitions of horizontal and vertical separation are opposite of mine. To me: Horizontal separation is the amount of "daylight" between the legs. Vertical separation is the distance apart the feet are, up and down, along the centerline between the legs. (like riding a bike with one pedal up and one down)(not much distance away from the centerline but quite aways apart vertically) At least that's how the coaches I know have been talking about it since 1984.
Agreed...
Slatz, while the definitions are not the most important part of this I wanted to provide a diagram that would explain the definitions that I planned on using for the discussion. After reading the thread on PMTS everyone had a different definition for vertical separation (some saying that it was constant in diverging and converging tracks and others saying that it was variant). To remedy this I kept the horizontal component on the horizontal plane, and the vertical component (as the turn progresses) would be measured more toward the vertical plane, and of course in the horizontal plane in transition. Use the definitions in the diagram to keep congruency with the topic... and think about this: If I told you to look at diverging and converging tracks from above (as I have portrayed) and told you that those represented constant horizontal separation (suppose you knew little about jargon) you would probably completely miss the point of what I am presenting.

More important to the discussion is the difference between the two turn styles; which is what I would like to hear more discussion on. Which do you (all) see as the more efficient carved turn and why, and where does the efficiency stem from?

Later

GREG
Quote:
 Originally Posted by HeluvaSkier More important to the discussion is the difference between the two turn styles; which is what I would like to hear more discussion on. Which do you (all) see as the more efficient carved turn and why, and where does the efficiency stem from? Later GREG
Definitions...

Definitions...

I'll nitpick a bit on the definition of "efficient".

From the standpoint of edge lock and "pure" carving, I would venture to guess that the constant track-width method might result in a "better" turn. Done correctly, it probably produces a more consistently edged ski and a somewhat better carve. If the intent is to do as perfect a carved turn as possible, this might be the more efficient method.

If efficient means producing a good turn with a minimum of effort, however, then I like the varied track-width method. It seems to involve FAR less tension in the pelvis, quads, knees, and ankles. It seems like a much, much more relaxed (and relaxing) way to ski that can still produce a very good carved turn. To me, this is more "efficient" if the intent is to produce a good turn with the least possible physical - and mental - concentration.

And then there's aesthetics. It may be heresy on this forum, but I like watching skiers making the varied track-width turn infinitely more than the other. To me, in the tiny clips I've watched, Harald skis this way (and I like the way he skis). From my perspective, skifex skis this way in this clip:

And I like that skiing, too.
Nice post Bob, I concur.
I've spent quite a bit of time looking for just what you're talking about recently.
The diverging/converging track turn is most common in slalom (lately) while the other is seen more in GS.
First let me say that I would be totally confused if I tried to use the horizontal/vertical the way you describe so I'll just talk about "daylight between the legs".(I think anyone can understand that) I've been talking about this stuff since 1984 when flex gates first started to affect slalom technique. Aldo Radamus (USST women's coach at the time) used to call it "grouping". The best analogy we could come up with then is the bicycle one, that is: there's little daylight between the legs but the feet are the distance of the crank arms apart when one pedal is up and one down.
The use in slalom seems to be to tighten the line on the gate. Sometimes it's a very active, almost, stepping move and others it's more of a pedaling (like Rocca in the Hood Camp thread picture on page 10? I think)
GS uses the RR track turn in the straighter, flatter turns where the skis are rolled edge to edge and the parallelogram effect varies the daylight between the legs.
That's all I have time for now. I'll be watching this one with interest.
Thanks for starting it.
Greg,

I concur with the need to use the known definitions of veritical and horizontal separation.

Horizontal is not just about distance between tracks. Horizontal separation speaks to stance width. Vertical separation is what happens when you put a stance sideways on a slope while maintaining horizontal separation.

eg. sideways on, stairs, a comfortable stance could result in your feet being on neighbouring stairs. Your feet are farther apart than standing on a flat surface, but it is the vertical component presented by the slope that has increased this separation. Hence the term "vertical separation".

Vertical separation can just as well be created by tilting the body as opposed to the slope.

Using these known definitions, your two titles would be:

Variable Track Width (Constant Horizontal Separation)

By keeping the stance width constant, the track width will vary as the vertical separation increases at the apex and decreases at transition.

Constant Track Width (Variable Horizontal Separation)

It is only by varying the stance width, to accomodate the changes presented by vertical separation, that we can keep our tracks parallel throughout the turn. Our stance width must increase to a maximum during transition and decrease to a minimum at apex.

I can envision doing the latter with a weight shift to the inside ski at apex -- this will decrease the inside ski turn radius, and increase the outside radius.
Quote:
 Originally Posted by Bob Peters Definitions... Definitions... I'll nitpick a bit on the definition of "efficient". From the standpoint of edge lock and "pure" carving, I would venture to guess that the constant track-width method might result in a "better" turn. Done correctly, it probably produces a more consistently edged ski and a somewhat better carve. If the intent is to do as perfect a carved turn as possible, this might be the more efficient method. If efficient means producing a good turn with a minimum of effort, however, then I like the varied track-width method. It seems to involve FAR less tension in the pelvis, quads, knees, and ankles. It seems like a much, much more relaxed (and relaxing) way to ski that can still produce a very good carved turn. To me, this is more "efficient" if the intent is to produce a good turn with the least possible physical - and mental - concentration.
I can nit pick too. Most of us judge efficient by how our own body feels, whether or not we have full use of our natural born functional range of motion or not. Most of us don't. Some of us work at maintaining as much functional fitness as we can, some of us don't. Not saying this is true with you Bob, but this has a huge impact on our abilities on the slope. Even people who feel they are fit may have muscle imbalances and muscle overuse tenseness that restricts range of motion and interferes with the exection of technique.

So what feels tense and contrived for one may feel very natural and effective
for another. Then we need to really determine how we approach this issue, especially if we are going to discuss and make judgements about this issue in ageneral and universal way. What or whose standard do we use? I make judgements based on sound functional fitness standards, and then temper them with my own personal experiences and fitness.

Then there is the issue of how new movements feel compared to old familiar movements. Remember the old saying, "if doesn't feel strange, then there has been no change".

I can't really get behind one turn being better, while another is more efficient. Not sure how to interpret this. Maybe for you it is really that one way feels more familiar rather than more efficient. Though I think an argument can be made that for any given individual, what feels efficient will have some variation over what feels efficient for another.

From my own personal perspective, my tai chai practice combined with some funtional fitness work has breathed new life inot my 54 year old body allowing me to make some real changes in the way I ski, and my understanding of skiing. My oppinion has evolved on what is effective and efficient as a result, and my skiing has changed as well. Not sure where this leaves us though, except to say that what may feel awkward to one may really be efficient for many.

It raises questions on how we should be making assessments on these types of distinctions. Later, RicB.
Just so we can talk about something more in-depth than vocabulary I am editing the original post; and I even made a new diagram for you all... continue the discussion...
Later
GREG

EDIT: Now that the main edit has been done and we can all agree on vocabulary words and their defintions the discussion can go on. What I mean by efficient above, is simply the least amount of redirection and which circumstance can offer a better platform for carving. The redirection is the key to this discussion. I have even gone as far as pointing out a movement that one camp may completely deny the existence of...
Sounds like a consensus is building for descriptions of foot separation. I’m in the same boat as those who prefer vertical separation as visualized by the active skier’s own perception in the moment. We can easily look down and see if one foot is ‘higher’ or ‘lower’ than the other. Spectators watching from the side of the slope would just have to tilt their ruler accordingly.

I ski both techniques and find both work equally well. A desire for Personal Comfort and ease of movement leads me to ski more the converging/diverging technique than the continuous-width technique. I do prefer continuous-width method whenever I’m in tough conditions like Cascade Concrete or Coral Reef. In those conditions, it seems easier (and safer) to work with a constant stance-width.

I suspect any declaration on which is more efficient would be impossible to pin down unless we specify a whole host of situational parameters.

---
A while back I pecked away at the topic of Inside-Ski path Here.

I’d now add ‘Increased Inside-Ski Torque’ to the list of methods presented there to achieve a cooperative Inside-Ski path. We can just apply a bit more torque to the Inside-Ski than the Outside-Ski to keep both paths largely concentric (so long as that Inside-Ski doesn’t get to far ahead).

I also agree with some of the observations in thread that spawned this one that actual ski-paths tend to be less circular than we normally draw them. This has implications for the transition path of each ski as drawn above. I think the transition zone is a bit longer than we normally draw it.

---
Regarding Intentional redirection movements I think our choice of Weight-Transfer timing directly affects the path our individual skis take in relation to each other. Consider the thread where Bob Barnes posted his description of ‘The Perfect Turn’ some time ago. His description has the skier keeping weight on the old Outside-Ski right thru transition, as it becomes the new Inside-Ski.

In Bob’s Perfect Turn the weight-transfer takes place well after transition which immediately puts the continuously-weighted ski on a tighter radius than the other ski as both come out of transition.

Both methods drawn above require steering maintenance of the Inside-Ski, but Bob’s method reduces the need for such maintenance to a shorter section of the turn. An abrupt weight transfer at transition requires us to implement Inside-Ski steering immediately (Just an observation, not a slight - such maintenance is easy to do).

Bob’s late-weight-transfer mechanism works equally well with both a narrow and average stance. An abrupt weight transfer works best with a narrow stance because an increasingly large lateral weight-shift movement is necessary for anything wider than narrow.

---
One other item of consequence is Stance-Width and the Self-Correcting aspect of carving...

Even though we may have a “wide” stance due to large vertical separation of our feet, our legs will still be close together and nearly parallel - delivering nearly parallel edge-angles at our skis.

If we allow our carving skis to remain on a fixed-width path a problem develops: Unequal ski-edge angles.

As our former vertical separation translates into horizontal separation, our legs splay apart and create unequal edge-angles in our skis underfoot - forcing the skis to track different paths. Fortunately, these are converging paths.

A wide stance at turn Apex will naturally create converging skis as we become more upright due to our splayed legs and inward-tipped skis. However wide our feet may get vertically, converging edge-angles helps to bring us back to normal.

Of course, this tends to limit the practical (continuously imposed) width of our stance while carving. The self-correcting mechanism supports a diverging/converging technique more easily than a continuous-width technique. To keep a continuous stance-width greater than our hip-width we’d need to consciously impose unnatural leg contortions during transition to keep our skis apart.

Fun stuff to think about HeluvaSkier… Can’t wait for the CM/Base-of-Support path discussion.

.ma

PS: having odd Editing problems today - had to switch from Mozilla to IE to add any text to the editor ... (?)
Here is another (and more interesting) visualization to consider…

First, assume I’ve adjusted my Boot Cant such that I can stand with Perfectly Flat skis using my “normal” stance width of about 10" (the center of each ski directly down from the center of each hip joint).

Now I go out and ski the constant-width technique. What actually happens?

As each turn proceeds from Transition my normal, unchanged stance allows both skis to remain at very similar edge-angles so they start to track the same arc radius (not concentric arcs).

But as I proceed from Transition to Apex my increasing inclination to the surface causes my legs/feet to become closer together (horizontally) while my skis continue to track at about the same distance apart as measured on the surface of the snow.

This drawing of my legs/feet closer together (horizontally) gradually places my Inside-Ski more onto its Outside-Edge. Remember - my skis are only at the same exact edge-angle when my legs are parallel - but as my legs/feet are drawn together (horizontally) my hips are locked at the same distance apart in their sockets. {OK, if I add hip counter and pelvic tilt it changes things a bit... but bear with me}

The now slightly-higher edge-angle on that Inside-Ski (from 'converging legs') allows it to track a smaller radius arc with no extra steering input on my part.

From turn Apex to the next Transition my degree of inclination to the surface is decreasing thus reversing the whole process: My legs/feet are getting ‘wider’ apart (horizontally), my skis remain roughly the same width apart (on the snow surface), and that Inside-Ski edge-angle reduces faster than the Outside-Ski’s edge-angle.

What’s really interesting when we compare the constant-width technique to the diverging/converging technique. Consider the impact of this self-adjusting edge-angle idea with a deliberate narrowing/widening of ski-width on the surface: The constant-width model would actually require less intentional steering of the inside ski than the diverging/converging model!

Ok - the idea as presented was mapped out in a bit of a vacuum. In truth we have hip counter to contend with (reduces hip-joint distance in the frontal plane), tip lead and knee-angulation to consider, as well as a host of other inputs.

Still, it’s fascinating to consider what impact this has. We don’t really have a ‘collapsing parallelogram’ of two legs, pelvis and snow surface - we effectively have variable length legs and a pelvis that only tilts so far.

.ma
michaelA, you're on the right track here talking about 'extra' tipping of the inside ski. Note that does not occur in the diagram of the convergent/divergent tracks. The inside ski can remain at the same edge angle and the outside, and does not have to be further tipped inside, directed, carved, weighted, or adjusted in any way. Theoretically the inside ski can be at less of an angle than the outside ski... however this wouldn't be considered good skiing and would probably indicate artificially produced convergent/divergent tracks (increasing both horizontal and vertical separation toward the apex of the turn). Anyone want to add to this?
Later
GREG
Quote:
 Originally Posted by Bob Peters And then there's aesthetics. It may be heresy on this forum, but I like watching skiers making the varied track-width turn infinitely more than the other. To me, in the tiny clips I've watched, Harald skis this way (and I like the way he skis). From my perspective, skifex skis this way in this clip: And I like that skiing, too.
I don't think that skifex skis like harald at all. It looks to me like much of the weight is placed on the inside ski in this sequence.

Harald's turns are quite different, with more weight placed on the outside ski, along with a lot of counter and angulation. Skifex is almost all banking, with very little angulation, resulting in a weak turn. Harald's turns are very powerful, in contrast.

Here is a pic of harald:

I agree with DD223, Harald and Skifex are not skiing the same, but there is "something" that is staying the same in their skiing, and what I see staying the same is the leg seperation. Both legs are moving parallel to the sagital plane of the body, with very dynamic long leg short leg (extension and flexion). Though the skis on the snow seem to be moving together and then apart from an external perspective, the body mechanics say otherwise. Neither are pulling or moving their feet apart from each other horizontaly. The noticable big difference in the body mechanics between these two lies in the difference between inclination versus angulation, which produces different force biases between the inside and outside ski.

The other noticable thing happening in the two as I see it, is the difference in edge angle between the inside ski and outside ski. This requires very active inside foot and leg activty and funtional tension between the two, to keep guiding their skis and legs in a parallel fashion along the sagital plane. To me the ski track divergance and convergance are simply an outcome of high edge angles and the required long leg short. Physics and physiology. Later, RicB.
Quote:
 Originally Posted by RicB To me the ski track divergance and convergance are simply an outcome of high edge angles and the required long leg short. Physics and physiology.
Well said. Generally speaking, when I see someone leaving parallel tracks I see a skier that is riding the radius of the ski (very little if any extra bend in the ski) with alot of weight on the inside foot.

When I’m carving I like to ski as efficiently as possible while bending the outside ski. This means a relatively light short inside leg so I can drop into the turn for bigger angles. I don’t carry much weight on my inside ski. If I did my outside ski wouldn’t bend nearly as much AND I’d be tiring out my inside thigh muscle because it would be carrying a good bit of the forces of the turn rather than allowing my skeletal system to carry those forces (allowing the skeletal system to carry the bulk of the forces generated in a high G turn is efficient skiing).
Max,

With all respect, ski-fex is showing very high edge angles without skiing as you suggest.

Inefficiency is usually reserved for describing the tail pushing, braking, defensive skier. I see that ski-fex is skiing extremely efficiently, as there are no such moves occurring.

The load is spread between both legs, and skeletal alignment is excellent -- it would simply not be possible to do what ski-fex is doing with inclination alone and not be skeletally aligned, ie, in the back seat and staying upright with quad power.
Quote:
 Originally Posted by Max_501 Well said. Generally speaking, when I see someone leaving parallel tracks I see a skier that is riding the radius of the ski (very little if any extra bend in the ski) with alot of weight on the inside foot.When I’m carving I like to ski as efficiently as possible while bending the outside ski. This means a relatively light short inside leg so I can drop into the turn for bigger angles. I don’t carry much weight on my inside ski. If I did my outside ski wouldn’t bend nearly as much AND I’d be tiring out my inside thigh muscle because it would be carrying a good bit of the forces of the turn rather than allowing my skeletal system to carry those forces (allowing the skeletal system to carry the bulk of the forces generated in a high G turn is efficient skiing).
Well, maintaining a parallel relationship of the skis at lower edge angle can leave tracks of a consistent width. I don't know that this is bad, just different type of skiing. How much weight is on the inside ski is usually a different matter than how consistent the tracks are in width. Weighting the inside ski is not in and of itself wrong either, just depends on what you want to accomplish.

I'm with you on the strength in length, and recognizing that a highly flexed leg is the weaker of the two, along with the outside ski bias developing in our turns. Lotta ways to get there though. Later, RicB.
I'm with BigE on skifex's skiing. It looks like excelent fun skiing to me. She looks like she is having a blast. I also would venture that anyone that can ski like this can probably ski in any fashion they want. Meaning traditionaly, like Harold. She looks like my snowboaqrd cohorts arcing and laying their inside palm on the snow. Later, RicB.
Quote:
 Originally Posted by RicB I'm with BigE on skifex's skiing. It looks like excelent fun skiing to me. She looks like she is having a blast. I also would venture that anyone that can ski like this can probably ski in any fashion they want. Meaning traditionaly, like Harold. She looks like my snowboaqrd cohorts arcing and laying their inside palm on the snow. Later, RicB.
I would also venture, although it's hard to tell for sure because the quality of the footage is so poor, that the slope she's skiing is NOT fresh-groomed corduroy. It looks to me like she's going in and out of some small-to-moderate sized moguls.

Pretty darned smooth, high-angle skiing if you ask me.

I would love to be able to ski like that.
Quote:
 Originally Posted by BigE Max, With all respect, ski-fex is showing very high edge angles without skiing as you suggest. .
I have no problem with the skiing I see demonstrated by SkiFlex. I also don't see it as being much different that what I described. Looks to me like she is handling the majority of the G's with an extended outside leg. Also demonstrated is a very nice flex during the release.

Quote:
 Originally Posted by BigE Inefficiency is usually reserved for describing the tail pushing, braking, defensive skier.
Anytime you use unrequired muscular effort in a turn rather than using the skeletal system you are using more energy which is ineffecient.
F=ma.
For the amount of acceleration skiflex's body is undergoing she doesn't need to straighten a leg to take the force. Her CM is travelling a path inside that of her skis, but accelerating less, like a dog chasing a hare. If she wanted more gs she would problably ski more like HH.
There are lot's of fun ways to ski, if your not so much concerned about your direction and just want to basically go down the fall line, you can play with more dynamic transitions, getting bigger angles without turning more. If you have to get around an obstacle you ski a little differently.

You guys make it too complicated, but it is summer after all. It's really just about putting those edges and bases where you want 'em and at a higher level, shaping them (at a lower level sidecut ski flex characteristics and tipping angle will do enough shaping to get you by) it to adjust their and your path while staying balanced and in control.
Quote:
 Originally Posted by Ghost F=ma. For the amount of acceleration skiflex's body is undergoing she doesn't need to straighten a leg to take the force. Her CM is travelling a path inside that of her skis, but accelerating less, like a dog chasing a hare. If she wanted more gs she would problably ski more like HH. There are lot's of fun ways to ski, if your not so much concerned about your direction and just want to basically go down the fall line, you can play with more dynamic transitions, getting bigger angles without turning more. If you have to get around an obstacle you ski a little differently. You guys make it too complicated, but it is summer after all. It's really just about putting those edges and bases where you want 'em and at a higher level, shaping them (at a lower level sidecut ski flex characteristics and tipping angle will do enough shaping to get you by) it to adjust their and your path while staying balanced and in control.
She's getting some pretty high edge angles, in my oppinion, she just isn't angulating, and I would say her transitions are pretty dynamic too, with the knees up into the chest through transition. Thanks for simplifying it for us Ghost. Later, RicB.
Quote:
 Originally Posted by Ghost F=ma. For the amount of acceleration skiflex's body is undergoing she doesn't need to straighten a leg to take the force.
Maybe we aren't looking at the same thing. I see an extended outside leg and a bent inside leg when looking at SkiFlex.

If your legs are flexed its more work regardless of the g forces involved because the muscles are contracting and working harder than they do when your legs are straight. Thats what I was getting at. Now, add speed to the equation and the forces increase so if you continue to carry weight on a flexed leg you are going to work much harder than if you carry the weight on an extended outside leg.
Quote:
 Originally Posted by Max_501 Maybe we aren't looking at the same thing. I see an extended outside leg and a bent inside leg when looking at SkiFlex. If your legs are flexed its more work regardless of the g forces involved because the muscles are contracting and working harder than they do when your legs are straight. Thats what I was getting at. Now, add speed to the equation and the forces increase so if you continue to carry weight on a flexed leg you are going to work much harder than if you carry the weight on an extended outside leg.
What you say is true;she is definetely not saving her energy. She mostly doesn't quite straighten out that outside leg. Instead she allows herself to go over the skis sooner without getting her CM so far away.

I suppose with a straight outside leg and some wicked angulation you could still touch the snow, but I like her way of doing it better.

Oh, I'm looking at the grainy vid in Bob's post.
Ok, I've come back to this after being unable to spend discretionary time actually reading Epic...

What you are calling "constant vertical separation", I would call "constant track width", since "vertical separation" to me is the distance in the tib/fib axis between the bottom of the two skis (zero with two flat skis, max during the belly of the turn).

Anyway, that said, I find the discussion hasn't gone in the direction that I expected. I find the diagrams interesting in that they show fairly consistent change in curvature of the "constant track width" turn for both skis, while showing a fairly dramatic change in turn curvature at the top of the turn in the "constant stance width" turn (what I think you call the "constant horizontal separation turn").

Do folks here think that's accurate?

Why or why not?
Just popping in.
What hit me about the video of Ski Flex is what I'd call "banking" also a noticable "A" frame in some transitions. Not necessarily bad, just a different style.
One thing coaches look for are, when viewed from the front, parallel lines through the joints of the ankles, knees, hips and shoulders.
The ankles and knees will usually be that way always. If the hip isn't parallel there is usually a fair amount of tip lead. Generally if the hips don't line up the shoulders don't either. Keeping things parallel all the way up takes a "strong inside leg" for the hips that creates angulation and levels the shoulders.
That's all for now.
Quote:
 Originally Posted by HeluvaSkier Even though your tracks’ vertical width stays constant throughout the turn the horizontal separation that you have actually gets smaller as the turn progresses toward the apex, and then grows as you progress toward the turn transition. If you are obtaining very big angles this requires a very wide stance in transition and will result in a very narrow stance near the apex. Interestingly, even though you are keeping parallel ski tracks all the time, you are constantly making very small rotary movements to keep your skis parallel and to keep the inside ski on a smaller radius. These movements grow to be quite big as you guide the inside ski through the turn, especially if your goal is little or no inside tip lead.
Okay, based on the diagrams that I drew the above statement is technically correct, but it does not reflect normal definitions of vertical and horizontal separation. Technically what I labeled vertical separation is the resultant ski track width as a result of vertical AND horizontal separation. Therefore a turn using constant track width has varied vertical and horizontal separation. Here are twp (finally) proper diagrams to illustrate those definitions:

Hopefully those two illustrations can help this along a little bit, but please not that the separation and the definitions of it have little to do with the focus of what I was trying to present (I will write another post for that though). If anyone has any interest in me going back to edit the original post to stop any confusion you may or may not have ahd I will do that, but since we should all play by the same rules I figured I would post the information in a separate post. If it helps, replace 'vertical separation' that was used in the first post with the resultant from the green triangle diagram and you will have a complete (and proper) picture of what I was trying to show originally. The importance of what is going on lies with the inside ski...

Later

GREG
Greg, that aligns with my thinking... thanks...
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