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Rotation Impossible

To rotate or not to rotate, the debate rambles on, and on.

I believe what we are looking at here is so close to the margins of turning a ski as to be almost irrelevant. The moment a ski is tipped to gain any significant edge angle, rotation of the foot in the direction of turning becomes near impossible. You just try it, it lifts the tail and digs the shovel, and it is only dorsiflexion that actually could turn the edged ski. not rotation. A tipped leg has no suitable rotational movement available to it to either tighten a turn or do anything else of that sort.

So what we are looking at is rotation of a flatish ski at the neutral point between turns where a small rotation could initiate a turning, or steering angle as LeMasters calls it. Call it guiding if you like, but once the turn is underway and the forces create an inclination, or a deliberate tipping is made, effective leg rotation is impossible. Thereon in, the turning is due to the ski's own deflection/bending.

So what is all the fuss about? Could it be that rotation is misunderstood and it's delayed attempt can only produce a skid if applied after the initiation?

It's Friday and I feel a 'rap coming on...

Rotate then Wait!
but rotate too late
(never more than second rate).

So just plain weight
the ski, it's shapely tips,
and ride it bent,
(A Carving Ski from Heaven sent),
and drop those hips
Hip Hip Hooray
HH Hooray,
HH Hooray,
Enlightenment,
The Tip Top Club
(The 97 percent).

Anon
Daslider I agree with you if we are skiing on one ski but disagree with you the minute we ski on two and here is why.

On one ski, the minute we edge, we have only upper body rotation as a source of rotary because we have one edge. The minute that I have two edges with separation between the two I can create rotary trough differential braking. The same thing that lets a bulldozer turn.

If I flex the inside ankle more than the outside ankle and tip the inside ski ever so slightly more than the outside ski I create more drag and braking action on the inside ski. That sets up a fulcrum between the inside ski and the outside ski. This is called the fulcrum action in independent leg steering. It has little to do with twisting you're feet.

This fulcrum action is greater the wider our stance is and is why it is easier to turn sharper in a wider stance, than a narrow stance. Notice I said turn, not pivot. A dozer that locks a track can turn much tighter than the average car that pivots its front wheels. This action is why I ski a wide stance in bumps and steeps.
"the fulcrum action in independent leg steering"

this is very exciting: a new (to me) idea and one I'll need to think about some more, although I can see straight away it has nothing to do with twisting, but presumably does use dorsiflexion? What does it feel like to ski this one?

Thanks Pierre, another turn in the Damascus road.
daslider, its the difference between driving a bus and a bobcat. Yah better be light on the touch with the bobcat if you want any kidneys left.
Pierre's right about the fulcrum movement. We've worked with that a long time.

Even so, I think that
1. Edging cannot be done without some rotational movement in the ball joint at the hip.
2. If you keep "torquing" the turn when it's on its edge, you tighten it some. If you do that too much, you overwhelm the edge and the platform breaks down. If you do it too little, the turn is way less dynamic and powerful.

I really feel as though my body is engaged in a maintenance of a twisting force to some degree all the time. It feels like it has to be done in balance with the edge/pressure.

It's not the classic rotation that dictates that the skis turn when the rotation stops. It's more like turning the top of a jar with my hand. I guess it's really what Pierre said, because you've got to have a fulcrum to operate the hand from.
I like you're additions weems thats pretty much the way I feel when skiing too.
Nor can I agree that rotation is not possible.

I agree with Weems, n Pierre. Rotational force applied to an edged and arced ski that may not wag the tails out is still a rotational force or torque that can be effective in regulating tip engagment and affecting the radius of a carved turn (exactly as is alluded to but discounted in lead post?). If you roll/tip a foot with enough consistant intent and enough duration to produce consistant torque, the kinetic chain (body genius) responds with rotation of the femur in the direction of the tipping in a pretty direct proportion and effect to the intensity of the rolling/tipping of the foot that enhances ones ability to guide the direction of the skis. This resultant rotary force has more of less impact on the steering angle of the ski proportinate to its edge angle on hard snow or the density of the snow in unpacked conditions. This resultant rotary can be activly augumented, but shifting intent to those large muscles disrupts the more efficient process generated from the feet. But it is always an option if what you want to do is suddenly skid more and carve less to serve your intent/tactics. However, there is a huge differance between a skilled skier using rotation by intent and an un-skilled skier doing it because they know no other options, or worse yet being taught leg rotation first instead of foot focus activities as cornerstone movements to beginners.

Rotary movements exist. From a simple bio-mechanical awareness this is pretty indisputable. That the paths and orientation of the feet and the CM have different sizes, shapes, and direction reflects rotary movements within the body, whether by effieient effect or inefficient cause. Like Weems suggests we most always got some going on. Sometimes we allow it, sometimes we cause it, sometimes just manage it, but it is there.

It is use/mis-use of rotary instead of other more efficient options that is at the heart of the issue. The crux is that there is still a general yet-to-be-comprehensive, but emerging [img]smile.gif[/img] , awareness of "order of movement" priorities for developing efficient and effective movement patterns that support ongoing learning reflective of modern comtemporary skiing vs. same-old, same-old traditional ones that enhibit rather than enable long term learning potential.
:
Arc [img]graemlins/thumbsup.gif[/img] I don't think everyone is going to catch it though.
daslider,

Put on a pair of shorts and draw a vertical line down your femur with a marker. Go stand in front of a mirror and laterally rotate your knee. Move it to the outside with perhaps a touch of abduction. This essentially is tipping your knee. Watch the line you have drawn.

[ March 13, 2004, 05:25 AM: Message edited by: Rusty Guy ]
Thanks Pros

those are very usefull answers and food for thought (and even experiment if this printemps holds off a bit longer).

I can see the fulcrum stuff and Rusty's marker pen reaffirms the hip-knee relationship, but I still don't see how the main gripe with rotation per se isn't valid when it seems to me that it is actually impossible to rotate an edged foot at the ski level other than by dorsiflexion. Granted there is some effective rotation from the hip, but even this isn't in the optimum axis once the ski is tipped.

I can also see that when the whole picture is viewed, 'rotation wrong' is trite, but at an elementary level telling people to twist their turning foot actually doesn't work once the foot is tipped on edge. This then blocks the progression to riding an inclined ski. Or have I got the biomechanics wrong here?

In view of this, the gripe with the snowplough imo is misfounded because it is the exclusive teaching of outside foot rotation that is at fault. Rotation does have its place, ironically more so at higher levels. Pierre's comment elsewhere about the pmts package producing a seductively elegant product but also a self-limiting one seems spot on.

thanks for all your help, I wish i'd discovered Epic years ago.
Quote:
 rotary trough differential braking
God bless America [img]graemlins/thumbsup.gif[/img]
Question.

If the foot cannot actually rotate/turn in the direction of travel when edged (please use descriptions above for clarity) what effect does attempting to turn the foot by activating the muscles and generating torque forces have?
I think one of the "rotary bad" sources is that many (I'd even say "most") recreational skiers rotate their legs and/or bodies so powerfully that they overwhelm the platform cut by the edge and never give the edge a chance to slice at all. This movement is usually done at the start of the turn to throw on the brakes before the turn ever gets anywhere. (note here, Bob Barnes perfect question: why turn?) We often use the word pivot to describe it because that seems to imply to us a very quick redirecting of the ski against little resistence from the snow. When you do it, it's damn hard to have the edges engage.

I also believe that the cleaner the carve, the less this cranking movement (I got so tired of the argument over vocabulary, I just call it "crank"). However, it's still there to some degree and the goal is to do it little enough so the ski doesn't break out of the platform. If you need the turn to go generally slower, you decrease edge angle some and increase crank. In this way the edges still work (the sidecut and pressure still engage the snow) but there's an increase in friction throughout. This is what I believe Eric DesLauriers means when he says to butter the turn. (I love that phrase.) This differentiates it from pure slicing. A good thing in the steeps and lots of other places.

As someone said in this and the other thread, it's just part of skiing. The key is to know your purpose. Vary the type of input according to what you're trying to do with the ski.

I'm going in this morning to do a little piece on TV in Aspen about skiing. I may talk about rotary (sorry Si), may talk about crank (yeah!), but I'm definitely gonna tell 'em to press forward with hips and shins against the inside/front of the boot!
Quote:
 I can see the fulcrum stuff and Rusty's marker pen reaffirms the hip-knee relationship, but I still don't see how the main gripe with rotation per se isn't valid when it seems to me that it is actually impossible to rotate an edged foot at the ski level other than by dorsiflexion.
daslider you keep beating that horse so I am going ot give him a rest. In addition to a fulcrum type of rotary there is the type of rotary that twists the shovel into the snow and it is effective. No it doesn't work by twisting the feet into the snow. I works by setting up powerful positions in stance. If you extend the inside knee to move the hips forward, pinch the outside hip and bring the outside hand forward and down towards the tip of the inside ski (upper body rotation) this will set up powerful rotation of the tips into the turn. The shovels will dig and the turn tighten dynamically. This is exactly what the racers were doing a couple of years ago.

Now in racers you see more fulcrum turning with more whole body inclination. Its a stronger position on the knees. I use fulcrum turning almost exclusively. I can't really use the shovel rotary as my heels will lift in telemark and my knees just don't appreciate the torque. [img]smile.gif[/img]
Lets see, bad rotary. Ahh, move the hips over the back of the inside ski, twist the outside ski then, transfer weight and brace on the outside ski, lift and bring the inside ski to parallel, bring the inside hand back, lift the outside arm. Pray you are not on ice.

Then there are the belly skiers. These are large men dressed in Carhart coveralls with an orange hunting hat. They just kinda throw their belly in the direction they want to go and their skis are whipped into sumbmission and instantly pivot while parallel. Up goes the outside hand back goes the inside hand
Quote:
 Originally posted by Pierre: Then there are the belly skiers. These are large men dressed in Carhart coveralls with an orange hunting hat. They just kinda throw their belly in the direction they want to go and their skis are whipped into sumbmission and instantly pivot while parallel. Up goes the outside hand back goes the inside hand [/QB]
Now you have struck a nerve. I just went to the Carhart outlet in Longmont and outfitted the whole family.
Dang Rusty, Tractors Suppy has them cheaper. So does Landmark farm services.
daslider, you need to think more in terms of what happens to the skis. No matter how much or how little they are on edge, there is a way to apply rotary force to them with your legs. Just point the tips into the turn and let your body figure out the exact mechanism. Or don't, and just use the sidecut. It's a rare situation when you are forced to do one or the other, so don't get all bent out of shape about it.
Quote:
 Originally posted by Nettie:Question. If the foot cannot actually rotate/turn in the direction of travel when edged (please use descriptions above for clarity) what effect does attempting to turn the foot by activating the muscles and generating torque forces have?
Nettie,
The effect on an edged ski of rotational torque around the axis of the lower leg shaft is an enhancement of tip engagment. When we become aware that in linked ski turns the ski virtually goes from shallow pitch to steeper from transition to falline, we can percieve how this rotational torque (hopefully as a kinetic chain result from progressive rolling/tipping intensity of the feet and not by trying to 'twist' them) can be very effective in keeping the ski tip engaged as it essentially skis over a dropoff into the falline. Without this effect, the tip cannot maintain a consistant effective engagement.

The lack of this rotational torque very is evident in park-n-ride skiers who's skis are staticly tipped, but no longer tipping (remember skiing is a verb sport). You see their turn radius lengthen thru the falline and then tighten some as their ski regains tip pressure by skiing thru the virtual steep to shallower terrain compression from falline to transition.

You can experience this effect by standing with initial whole foot fore/aft pressure and then slowly, strongly, and continously rolling/tipping both feet in one direction. You should experience a progressive increase of pressure toward your toes on the edged side of your feet. This also brings your balance to the forebody of your feet (the body genius at work). Note: skiers who less rfficiently tip from the knee (vs the feet) are only are afforded a less effective result.
[img]smile.gif[/img]
Quote:
 Originally posted by Arcmeister:
quote:
originally postd by nettie: If the foot cannot actually rotate/turn in the direction of travel when edged (please use descriptions above for clarity) what effect does attempting to turn the foot by activating the muscles and generating torque forces have?
The effect on an edged ski of rotational torque around the axis of the lower leg shaft is an enhancement of tip engagment.

...this rotational torque (hopefully as a kinetic chain result from progressive rolling/tipping intensity of the feet and not by trying to 'twist' them)</font>[/quote]:
Mind you that's not hard!

I was thinking about the effort required to twist the toes, say to the left towards the other foot, whilst the knee remains facing forward.

Is this what you mean by 'trying to twist' the foot?

When I try rolling and tipping a foot towards the same direction, it lifts the outside of the foot with no rotational torque.

If I had a ski on it might give me more edge and dig the shovel in if I extend the ankle at the same time. Won't that just mean riding the ski arc, only adjustable to the limits of effective edge angle?

The turning of the feet below the ankles at ALL points in the turn (blended of course) is advocated in clinics by CSIA IVs including members of the demo team.

Is this what is being avocated as less desirable by comparison with the 'kinetic chain' of your post?

Willing to adapt but still : !
Nettie,

Have them hold your forefoot flat on the floor, or your ski tip flat on the snow.

You roll/tip your foot, inside your boot or shoe, toward your little toe edge with progressively increasing intensity.

You should be able to feel the kinetic chain fire progressive muscle engagements up your leg from the small muscles on side of leg that are rolling/tipping foot, to the eventual recruitment of the large thigh/hip rotator muscles that rotate the femur in the hip socket in the direction of the tipping. This is the very efficient resultant rotary I am refering to. It only works in proportion to the intent and intensity of the rolling/tipping of the foot which keeps the k-chain engaged. If the feet go passive you loose refinment options and your only option is to maul the process with big muscle brawn vs small muscle dexterity. Both are real options. Some people like the feeling of physically dominating terrain or snow conditions and some like the feeling of slicing and dicing with more finesse. But having a choice of options is what it is all about.
Ah, what do you know, Arc? You skied into the river at Snowbird.
Ya but I was efficient in the air!
Yeah, but did you rotate?
I think the correct term is Floatate as he is still here [img]graemlins/evilgrin.gif[/img]
Quote:
 Originally posted by Arcmeister:You roll/tip your foot, inside your boot or shoe, toward your little toe edge with progressively increasing intensity. You should be able to feel the kinetic chain fire progressive muscle engagements up your leg from the small muscles on side of leg that are rolling/tipping foot, to the eventual recruitment of the large thigh/hip rotator muscles that rotate the femur in the hip socket in the direction of the tipping.
Arcmeister, Ok, now I can relate to some of the intent of the posts. That movement has been describe to me on snow as 'ski like you're bow-legged' or for the oldsters 'ski like you're John Wayne' (on a big, fat pony for the kids). This tends to recruit from the knee outwards rather than from the foot upwards I'll admit.

(Aside: this seems to be the skiing equivalent of stand up straight, don't slump: without ski boots my ankles and knees drop to the inside slightly if I don't keep active muscle tension.)

I can feel and see how it rotates my knee out and obviously the hip joint is rotating to see this at the knee (hinge joint). I can't feel the torque at the foot but unless the knee is really unstable, I can understand that is putting a torque on the ankle (not foot) as well. I don't know enough about the mechanics of the ankle/tib/fib in lateral movement to know how much slop is in there and what the resultant is at the toes (my kinesiology books are back at my mum's gathering dust).

Am I right in thinking that some/most of the force trying to rotate the ski (the actual aim/intent) is actually transmitted via the upper section of the boot and not the foot at all?

If I try to twist the toes in the direction of the turn, I do apply torque to the boot and again get the ski to rotate. This makes different muscles fire and feels like I am 'throwing' both my hips out to the side. The feeling is more obvious if I use the right foot moving the toes to the left rather than the left foot moving the toes to the left.
Is this what we are trying more to avoid?

(I can get a feeling of hip and pelvis lock turning left in the later third of a turn but not turning right. My left ankle dynamics are quite different due to injury on that side, maybe the injury is helping!)

Finally, you are talking about inside foot for this kinetic chain (left leg going left). Is the pivoting (rotating of the ski) torque initiated by a movement of the inside leg muscles and transmitted to the outside ski via pelvis etc.?
Or, is there active pivoting to be done as regards pivoting the outside ski as well?

Also, are we steering the skis all the time (using E & P, especially P through the finish) and, unless in a full carve or full skid, always using both pivoting and edging?

Terms I understand:
Pivoting=turning ski flat around central pivot point.
Edging=tipping ski over to change edge angle.
Steering=to blend both as required to direct skis.
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originally postd by nettie:
If the foot cannot actually rotate/turn in the direction of travel when edged (please use descriptions above for clarity) what effect does attempting to turn the foot by activating the muscles and generating torque forces have?
--------------------------------------------------------------------------------
in the right hands a very good effect. My concern is that this concept is hopelessly misconstrued by lower level skiers. Perhaps we just need a change of language, but the pivot or rotation of a flat ski (around the axis of the lower leg) is not possible once that ski is tipped, and by possible I mean in the 'twisting' sense. Although the effect of digging the shovels may be beneficial (as a coda to the main tipping action), if it is still thought of as a 'twisting' movement, it leads to all sorts of problems. Like with anything, once you can do it , it isn't a problem.
Quote:
 Originally posted by daslider:what effect does attempting to turn the foot by activating the muscles and generating torque forces have? Daslider: in the right hands a very good effect.but the pivot or rotation of a flat ski (around the axis of the lower leg) is not possible once that ski is tipped, and by possible I mean in the 'twisting' sense.
But even though the ski may not actually BE pivoting there will still be a sideways (along the surface of the ski) force which is greater on the front than the rear when twisting the foot.

Something has to be pushing back at my foot.

What happens to the turn/ski when you add or subtract this force?
Let's look at this from the other end. What (if any) problems flow from new skiers' understanding of rotary movements and how are such skiers most likely to try and develop such movements?

Of course rotation isn't impossible, but efforts to continue the twisting possible on a flat ski, onto an edged turning ski as the primary turning strategy are ineffective. In fact it is a disincentive to effective edging as the actions of twisting and edging seem to oppose each other.

Isn't it better to start wedge turning with footrolling and inside foot guidance?
daslider:

Not want to answer or don't know?

I want to understand what everyone is talking about. I work from the movements and forces I can impart to my skis (tip the ski, pivot the ski, at the moment) and then backwards to find out the cause; Going the other way is too open-ended.

I thought the question itself was quite simple.

You have something to impart but I don't get it.

You say that 'in the right hands, a good effect'. What is this 'good effect'? :
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