Why not a wider stance?

[onyxjl]

In learning about PMTS, it has been recommended to ski with a stance which is roughly as wide as where your legs naturally extend from your hips. In reference to carving turns, I have heard reference that some people advocating widing your stance. Even if this is incorrect advice, what is the reasoning behind it?

My initial thoughts are along the lines that in PMTS, a skier is taught to retract their inside leg which creates vertical seperation of the feet and allows the skier to reach high edge angles. If one were to take a ruler and measure the distance between the skis, the distance becomes greater until the fall line is reached and then begins to decrease again until the next edge change.

If the skier were to start in a wider stance, the skier has vertical seperation at the fall line, but the distance between the skis is roughly the same as it was at edge change.

To put it another way, if the skier stuck a rubber band around their feet, a PMTS skier would stretch the band quite a bit but a skier in a wide stance to start with would not.

Is the skier who starts in a wide stance trading the need to vertically seperate their feet a further distance in exchange for having to move their CM a further distance at edge change?

[onyxjl]

I found my answers in the Functional Vertical Stance thread. Somehow I missed it the first time around.

If anyone isn't sick of beating this to death, by all means reply.

[Jim Ratliff]

To put it another way, if the skier stuck a rubber band around their feet, a PMTS skier would stretch the band quite a bit but a skier in a wide stance to start with would not.

But the distance between the feet as shown by the rubber band isn't the definition PMTS uses for stance width.

Stand on the floor with you feet at normal width (say 12" apart). Raise one foot 18" off of the floor. Your stance width hasn't changed, only the distance between your feet has changed. The "parallel" vertical lines that could be drawn through your legs and feet are still 12" apart.

You are correct that if someone then leaned you over until your raised foot touched the floor, the contact point with the floor would be more than 12" but that is irrelevant to the explanation of "stance width".

To take your other question about starting in a wide stance. Biologically, what happens if you have your feet/legs two feet apart and raise one foot 18" and then have someone tip you over until you make contact with the floor. I actually have trouble visualizing this, but it seems like the angles from the hips get all messed up, and I believe the wide starting point actually locks you up in trying to get that raised foot tipped over onto the floor. More than likely, your legs come back together to a more "natural" width.

[Jim Ratliff]

I'm not an instructor (or a racer), so be patient with me, but I'll play along for the intellectual stimulation. I'm also continuing your implicit assumption that all weight is on the outside ski (i.e. the CM is balanced on the outside ski).

I understand your diagram, but it looks to me like the reason the CM moves less is because the whole body loses some of it's downhill position (in other words, an implicit shift back up the hill by the amount that is saved).

Here's my verbal picture.
Assume narrower stance is 12" and that wider stance is 24". Assume that when the stick figure person is at the 45 degree angle, their CM extends laterally (sp?) 2.45 feet from the base (the square root of a 6' person).

1. If they were on a narrow mono ski, the CM would shift 5.9 feet (2.45 from the left to 2.45 to the right). The fulcrum point doesn't change, the circle scribed by the ski during the transition is continuous except for the change from one edge to the other, so the width of the ski).

2. Narrow stance. The CM shifts 5.9 feet minus the transition to a new fulcrum point up the hill by 12", for a net CM movement of 4.9 feet. The arc scribed by the new stance/uphill ski begins 12" up the hill from where the other turn ended. (NOTE that I am NOT saying the the CM was ever moved up the hill). As you say, CM just moves down the hill less than when the stance width was an baseline 0.

3. Wider stance. The CM shifts 5.9 feet minus the displacement of the fulcrum point up the hill by 24" for a total CM movement of 3.9 feet. The arc scribed by the new outside ski is two feet back up the mountain from where the old circle ended. As you assert, the CM moved 1 foot less than in the narrower stance.

I don't see the value of the 'lesser' CM movement. I assume that the argument is that the lesser CM movement results in quicker turns, but it looks to me like the quicker turn comes at the expense of loss of progress down the mountain and that it results in the CM getting down the hill slower.

Carrying on. If you assume that each carved arc from transition to transition has a 10ft diameter, then each turn with the 12" stance nets you 9 feet down the hill and each turn with the 24" stance nets you 8' down the hill??

Assuming skiers of equal speed turn to turn, then the narrow stance skier does 720' down the surface in 8 turns while the wider stance skier does that same 720' taking 9 turns and loses the race by a full turn? (minus whatever he saves by the assumed faster transitions)?

Seems that if the goal is to get the CM down the hill as quickly as possible, then the narrower the stance the better?

Your turn.

[NoCleverName]

Sorry, Rick, you have your frames of reference confused. Perhaps from the standpoint of the feet, they see the CM passing overhead from side-to-side, but from the standpoint of the CM, it sees the feet occillating back and forth underneath. Since it's the feet that are actually doing the moving, it's the CM that's actually stationary (i.e., no forces needed since no movement occuring).

Think if it as a big ol' grandfather clock running straight down the hill on rails, the pendulum moving from side-to-side. The CM of the system isn't moving much at all (and with a counterbalanced pendulum, not at all).

Therefore, your idea of the skiier "moving the CM" isn't occuring.

Furthermore, since in both cases you assume the skiers "look the same" during the extreme angulation of the turn (CM over the point of support creating the centripedal force to make the turn), the only difference has to be in the "return position" standing up during transition. Since the CM is longitudally stance-invariant when you are standing straight up (e.g., it might be higher or lower depending on stance, but it'll be the same side-to-side), the distance the CM travals from max turn to transition has to be the same in both cases.

Now, clearly wide stance has its uses during straight runs to maintain stability. That's because the two points of support for the CM allow you to react to random forces. But since the idea of turning from side-to-side is, quite the contrary, not to maintain a stable course, it's hard to see while a stability-enhancing measure like wide-stance is such a good thing.

[ydnar]

NCN

Nither feet nor cm are stationary. Both are moving forward at a fairly respectable speed, but they are on different paths. These paths cross so the feet are on one side of the cm then on the other side of the cm and neither feet nor cm have moved laterally both have simply continued on their respective paths.

yd

[milesb]

It seems to me that if you start a turn with a wide stance, at some point before maximum edge angle you are going to be moving the inside foot closer to the outside leg anyways, just because of the way the leg flexes. This assumes using inside leg flexing as part of the way to achieve edge angle. If you want to just huck the upper body into the middle of the turn and then try to get the edge angle to match, it's a different story. (But nobody's advocating that, right? )
So why not move the feet closer in the transition so that no compensating moves need to be made?

[HeluvaSkier]

Originally Posted by Rick
Which skier do you think will have to move his CM laterally the most from one turn to the next? Easy, the PMTS skier. As the PMTS skier is approaching the transition he's reducing the lateral separation between his feet by bringing his inside ski back towards his carving stance ski. This moves his old inside ski down the falline. This mandates that the CM also will need to be moved further downhill (to create a certain edge angle for the new turn) than if the old inside ski had been left in it's original uphill location.

Rick, that is where I was going with my mention of stance in an earlier thread (now in the classics section).

Later

GREG

[jbotti]

Wow, It's hard to not be continually amazed by these threads. Even for the non PMTS'ers posting, all of you know that one of the basic tenets of PMTS is that Harald does not agree with the wide stance concept. In reality the converstaion should stop there. It did for me years ago. Yet every year we seem to go through this same process where everyone who doesn't completely buy off on PMTS or worse, those that are offended by Harald, come here to post and try to show us that we and Harald are wrong.
Rick, you are less than genuine when you say you are here to learn. If you want to learn, listen!!! Heyoka says you ski with the big wide stance. I'm sure you rip. But I know that the first thing that Harald would tell you to do on the slopes would be to narrow it.
Why are we discussing this!!!
It's simple, if you want to disuss the merits of wide stance, do it elsewhere. Harald is not going to chnage his mind. More importantly none of you (and all of you know who you are) have any shot of learning anything while you continue to argue and disagree with the teacher!!
Do you remember what it is like to be taught?

I don't post on Epic fo a reason. Philosophically what most are syaing is opposed to the way I am learning. I don't try to tell them they are wrong.

Is life so boring and unfulfilling that you would want to come here and bag your head against a wall?

I have said it several times. Harald is here to teach and he will teach you if you let him. But he won't teach you your way. He will do it his way.

If you "really want to learn and explore PMTS" don't present to us reasons why the basic tenets are wrong or misplaced.

We don't teach the wedge, we promote a narrow stance, we try to carve as much and as often as we can, we don't believe in rotary movements or steering of any kind. But all of you already know this!!!

Be honest about your intention!!! These posts do not represent a true intention to learn!!!

[NoCleverName]

Ydnar: The purpose of my post is to demonstrate that Rick was mistaken about the distance the CM had to move laterally because of wide-stance vs. narrower-stance. I think they are about the same if not the same. So I was undercutting a potential argument in favor of wide-stance (in which I don't believe in).

About your paths: of course everything is on its own path but the CM does, of course move from side-to-side relative the skier as it has to because the feet and legs are moving side-to-side; any counter-balance will further move the CM laterally in an effort to get it right above the point of support over the ski to keep everything in balance.

I think the whole wide stance arg is kind'a dumb when you consider how hard it is to manoeuvre a tricycle vs. a bicycle, unless a certain group of instructors is recommending training wheels for everyone.

[jbotti]

Rick, the proof is in the pudding. I tried the other approach, and my skiing showed it. And perhaps more importantly I am really not interested in theory, I am interested in learning from someone who can get me the result that I am after. Whether you agree with his theroies or not, Harald is an amazing teacher and his methods produce results beyond what I have seen elsewhere and I am convinced that he would produce amazing results in your skiing and teaching, but it will never happen in the midst of you arguing theory with him or with others on this forum.

If you haven't noticed I will not spend my time debating skiing theory on the internet with self declared experts. I know how to learn and I listen to my teacher. Until I reach his level I won't question his word.

I'll say it one last time, It is the PMTS forum. It was set up and designed for those interested in learning and discussing the concepts behind PMTS. If you can't get behind these concepts why bother posting.
You live and work near Harald, why not go take a lesson with him?

Rick, If I really saw you genuinely trying to learn and grasp what Harald is teaching I wouldn't be saying a word. But your posts continually question, dismantle and on some level attack what Harald is espousing. Let's be homest about defensiveness and about who is definding their approcah to skiing. I am not defending, I am telling you that I am not interested in your attacks on our forum.

I actaully dislike your approach more than others because you try so hard to disguise your intention and perhaps you fool others who engage with you.
When people come here and just trash Harald at least their being honest.

Heyoka tells me I should go easy on you and that you are a good guy. Maybe we will ski together sometime. I won't hold a grudge. But I don't think you are being honest.

[NoCleverName]

Rick, it isn't necessary to move feet around to get the skis to come together. The outside ski is at a greater edge angle and decambered more than the inside ski. Therefore it has a tighter turn radius than the inside ski. The skis come together naturally because their courses intersect. As transition approaches, both skis become both less tipped and decambered the same resulting in similar turn radii. Eventually the skis become flat. At this time they run parallel; they are closer together because they were on different courses earlier.

Now, if you propose that you can keep both skis a fixed (wide) distance apart throughout an entire turn, then you are saying that the skis have to have different turn radii in order to keep them on parallel tracks. But of course, the outside ski would have to have a longer turn radius than the inside ski. Therefore, the outside ski requires less tip and decamber than the inside ski to have a longer turn radius. Sorry, you don't see that in any pictures, it's the other way around.

[HeluvaSkier]

jbotti, you are a true spokes-person for PMTS.

Later

GREG

[Jim Ratliff]

Now, let me offer something else for you to think about in your evaluation of this subject.

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And,,, the racer no longer loses height on the hill via narrowing. Thoughts on that?

Rick:
Keep in mind my earlier post that my experience, in baseball at least, is that fundamentally correct baseball is often unrelated to what you see the professional on TV doing. My answer to your question is, "I don't know." Sort of like a salesman with a 'bait and switch' you moved the discussion out of an arena I could comprehend and into one that I don't. I have no idea or background to determine whether what you describe is the best way for a racer to deal with the situation you have described.

However, since this started with a question about "why not a wider stance" are you saying that the predominant reason for using a wider stance is so that a racer can adjust to the gates by stepping back up the hill (I know, bad terminology)? I find that possibility rather appalling. If that isn't the predominant reason, then why did you lead us in this direction. That's sort of like saying that every high school pitcher needs to take a Luis Tiant wind-up (exagerated high leg kick, exaggerated rotation away from the batter and then back) because he might need that wind up IF he ever makes it to the big leagues.

Where is your simple and concise answer to the original question?

The biggest attraction of PMTS, to me at least, isn't whether it is the be-all and end-all to racers and high level skiers like yourself (although circumstantial evidence indicates that it provides a good basis for that level of skiing). The attractiveness is the simplicity and the conciseness in the explanation of the movement progression.

The first time I went bowling I found a pamphlet on the desk. It said stand like this, approach like this, roll the ball over the same dots on the lane, don't aim at the pins, adjust until you roll the ball between the 1 and the 3. My first game (age 16) was a 140, and I've been a good bowler ever since. There is also the 'story' of Einstein sitting in on another professor's convulated lecture. At the end, Einstein demonstrated/explained the same material in 10 simpler and more easily understood steps. True mastery, I believe, results in an ability to break down the subject matter into simply understood terms.

My opinion is that I haven't yet encountered anything (except your potentially contrived ski racing example) that reveals any fundamental shortcoming with a functionally narrow stance or that sheds any light on why a wider stance would be preferred?

By the way, I say contrived only because I don't have the knowledge to know if that is a real problem and if the approach you described is the preferred. I know that in car racing they often hold the current turn longer to position themselves for the next turn rather than just completing the current turn in the middle of the track. The skiing equivalent, I guess, would be holding the current turn longer and skiing back up the hill 1 foot rather than stepping up the hill 1 foot.

[RobertC]

Now, if someone would like to tell me if/how that conflicts with PMTS ideology, and if it does what benefit is derived from the extra narrowing movement I'd be interested to hear. Thanks

Is there a narrowing movement? As I understand it, and using the axis of the skier's body as a reference, the feet don't narrow in PMTS.
Say the skis are like bike pedals - how far apart are the pedals? I don't think many people would measure the diagonal distance. And as the bike goes round a corner, do the feet get further apart?
But I am not sure that images of racers muscling their way down the hill betwen the gates, on the edge of control, have much relevance to our skiing. (Well, not to mine anyway!) If you widen the stance the edge angles don't match naturally. That just makes more work - needs more strength and more adjustments. For me, at 50+ that's a huge minus.