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PSIA LIII skiing standards – real live vs. epicski? - Page 5

post #121 of 147
In his book, Joubert goes on to evolve rhythmic linked braquages into the wedeln turns of that era. He promotes this evolution of the braquage movements by reducing the initiating intensity and lengthening the duration of the rotary movements. This is our d.i.r.t. methodology as we have subsequently labeled the variations or duration, intensity, rate, and timing as applied to skiing movements.

The result of braquage is rotary force applied to pivot the skis. This was to produce turns, with the skis of that era, from the resulting deflection of them becoming oriented across the direction of travel at the time of the pivot.

As soon as modern skis are tipped to a slight edge angle, they begin to produce a steering/turning force component from their extreme sidecut geometry. This is most dominant any time a ski is not pure carving. As this sidecut steering engages and the skis/feet/legs turn more than the body, and the recruited movements that compliment the tipping of the feet reach the femurs, the result is the ‘passive’ rotary of the femurs being referred to. This recruited rotary in the femurs is necessary to allow the skis to turn more than the body.

The more carved the turn, the more square and stable the relationship of the stance leg’s orientation to the ski and the more this reflects as the pelvis turning out, vs. that femur turning in. As the pelvis turns out, the inside femur must be allowed by tipping of that foot, or caused if less skilled, to rotate in the direction of the turn to keep that ski on a concentric arc to that of the outside ski.

Observation of this is often miss-perceived as a cause instead of allowed to be an effect. True, if the rotary becomes ‘active’ enough it can become a causing force. But if the passive rotary were blocked and not allowed to happen, the body would always remain in a very square relationship to feet and skis. I think this blocking would also produce more park-n-ride vs. the subtle but rhythmical winding-unwinding seen in expert skiing.
post #122 of 147
I like it when smoke comes from my head from thinking of all the ideas you guys share with me. I have plenty to work on from the great feedback, but this passive rotary thing is gimped to me. I think that preturn Christies are way cool and still work great, but....

Is it true that in RR Turns passive rotary is responsible for the posture K Fry shows in the PSIA maneuver? From what I get from Bob Barnes it is.

If so, then the sequence of movements leading up to that photo went like this?... From a straight run (no body angles, flat skis etc.- clean slate, lets call it neutral), she tipped her feet and ankles; then with the skis on edge they began to deflect, she senses this as a rotary force on her skis, feet and legs, she allows this force to rotate her legs (below her stable upper body) just to the point of the appropriate amount of counter, then she stops it and continues arcing along on her way. Have i got that right?

Wait a sec. it's not over yet, she has to get "un-countered' and release the edges. She has got to let go of this turn and start another one to the other side. I assume the arcing skis are still trying to rotate her legs in the same direction. So how does she use passive rotary to unwind her legs? Is it some other force that does it? I don't know.
So... now she would flatted out the skis, but there is no passive rotary force available from the skis to unwind the legs, that would mean that her upper body is anticipated while she is on flat skis. Wait, now her anticipation wants to release and rotate the skis, and in addition, no neutral to start over again.
OK I am lost where did I go wrong.
When (if) you reply, please spell out how passive rotary works in Medium Radius Carved (Arced) Turns to align the body into counter.
Also, if deflection precedes counter (from the assertion that passive rotary actually causes it) doesn't that fly in the face of balance and the accepted role of the foot in skiing.
Are Ya sick of me yet, I hope not. I do not get this.
post #123 of 147
As I see it, gait mechanics is what enables passive rotary to be used to unwind from counter. Outside leg relaxation unblocks the pelvis and allows it to be realigned. The realignment occurs as the body unwinds and the free leg swings by the new stance foot.
post #124 of 147
Quote:
Originally Posted by BigE View Post
Bolter, that's not Bracquage. Bracquage demands that rotary force is used to pivot the skis. If you hold the skis, you get countering movements.
If braquage demands pivoting and Pivoting the skis by definition causes skidding then braquage can not be a part of arc2arc skiing. That is logical. If the premise that braquage must pivot the skis is true. I don’t think so, I may be wrong.
That said, there is an aspect of inside half lead that RickB mentions that is peculiar and will probably cause me to abandon the braquage brigade "our inside half lead comes from a rotation around the head of the outside stance femur. This is where the axis of rotation of the pelvis originates from, around the the outside stance foot and leg." This hints at sequential rotation which negates SiLR as an option. Braquage is fading but I can tell ya one thing it sure as heck is not Passive Rotary!! Just kidding.

If the rotary movement of the legs (using braquage) meets enough resistance (mired in spring mank) the upper body will counter? I don’t know, is that true?

Quote:
I don't think mixing gait mechanics with bracquage is possible, because gait mechanics does not use each leg to anchor the other. Gait mechanics certainly have a free/swing leg, and a stance leg, but the swing leg is not anchoring the stance leg
You are probably right but this is sticky because gait mechanics are founded on single limb support for a portion of the stride but in skiing we are stretching out the heel strike and both feet are grounded throughout the turn. Maybe this is where the two split and it is not an advantage to superimpose gait mechanics on to skiing through every phase. I have found (finally) a source for human locomotion and am trying to grasp it so I am of little authority now and maybe never will be. Bolter
post #125 of 147
Quote:
Originally Posted by Bolter View Post
Is it true that in RR Turns passive rotary is responsible for the posture K Fry shows in the PSIA maneuver? From what I get from Bob Barnes it is.
If so, then the sequence of movements leading up to that photo went like this?... From a straight run (no body angles, flat skis etc.- clean slate, lets call it neutral), she tipped her feet and ankles; then with the skis on edge they began to deflect, she senses this as a rotary force on her skis, feet and legs, she allows this force to rotate her legs (below her stable upper body) just to the point of the appropriate amount of counter, then she stops it and continues arcing along on her way. Have i got that right?
.
Is this part right? Be serious, why not just inside half lead (plus a little leg tilting) into this stance? I am responding to my own posts, not good. Bolter
post #126 of 147
It sure does look like I was incorrect to try to push heel strike back to initiation.
post #127 of 147
>>>>the ISIA stamp is for I(international) ski instructors... why shoudl the requirement to be able to teach in a second language be removed? If you want to stay home you do not need an ISIA stamp surely?<<<<

I made my ISIA very long ago in 1970. I have taught many lessons in my native German and in English. While in Germany and in Austria as well as Switzerland I found that German and English ski lessons are in the great majority. Somehow the Italians and the French tend to ski at home. Both Austria and Switzerland have a number of ski resorts frequented by international clientele, like Lech , St. Anton and Kitzbuhel in Austria and Saas-Fe, Zermatt and St. Moritz in Switzerland. In the US it seems to be Aspen and Vail.

If you don’t intend to teach at an international venue there is no point in belonging to the ISIA.

….Ott

post #128 of 147
Quote:
Originally Posted by Arcmeister View Post
In his book, Joubert goes on to evolve rhythmic linked braquages into the wedeln turns of that era. He promotes this evolution of the braquage movements by reducing the initiating intensity and lengthening the duration of the rotary movements. This is our d.i.r.t. methodology as we have subsequently labeled the variations or duration, intensity, rate, and timing as applied to skiing movements.

The result of braquage is rotary force applied to pivot the skis. This was to produce turns, with the skis of that era, from the resulting deflection of them becoming oriented across the direction of travel at the time of the pivot..
That is a nice summary, thank you.


Quote:
As soon as modern skis are tipped to a slight edge angle, they begin to produce a steering/turning force component from their extreme sidecut geometry. This is most dominant any time a ski is not pure carving. As this sidecut steering engages and the skis/feet/legs turn more than the body, and the recruited movements that compliment the tipping of the feet reach the femurs, the result is the ‘passive’ rotary of the femurs being referred to. This recruited rotary in the femurs is necessary to allow the skis to turn more than the body. .
Steering IMO is the rotary movements used to guide the skis along the direction of travel (DOT). This is a muscular activity to reorient the skis, to "point them" in the DOT. It is something we do to them. You can stretch it to include edging and pressure movements if you want. Of course steering is nothing if we do not include forward movement (momentum) ski design, deflection, etc to turn. BTW I do not see the modern sidecut as extreme.
"Passive rotary" suggests (IMO) that we resist the rotary force produced by deflection to control the amount of leg rotation. Why? Things have changed that much because of deep sidecut. I don't see it that way. It suggest that the skis will overturn if we do not do something to control them. Maybe this is where the misguided advice to detune your tips past the contact point arose. I sure don't.


Quote:
The more carved the turn, the more square and stable the relationship of the stance leg’s orientation to the ski and the more this reflects as the pelvis turning out, vs. that femur turning in. As the pelvis turns out, the inside femur must be allowed by tipping of that foot, or caused if less skilled, to rotate in the direction of the turn to keep that ski on a concentric arc to that of the outside ski
"The more carved the turn..." This selection from your post is fascinating. I do not intend to go off subject but we gotta get a distinction between "carving more" and arcing.

From its inception the ATS (ATM) of PSIA is rooted in three principles: A student- centered holistic teaching Methodology, the skills concept of Mechanics and the most revealing, if not at first obvious . . .Slipping skis as the innate base of support.
Slipping skis are at an angle to the Direction Of Travel (DOT). Sliding skis are parallel to the DOT. Sliding skis is the innate base of support for arcing. A totally different beast! Both slipping skis and sliding skis leave distinct signature tracks in the snow. Slipping, scrubs a pattern across the DOT. Sliding, presses a track parallel to the DOT.
Slipping combined with edging (and other moves/skills) has a potential for high amounts of friction. The friction potential of slipping and all skidded turns is crucial for ATS’ Methodology/Mechanics. It offers speed control at all levels of achievement.
The slipping ski is rudimentary to the ATS progression. Slipping starts in the Preliminaries as the gliding/breaking wedge and with skill development becomes the wedge turn. The Wedge Christie introduces parallel skidding skis. Parallel Christies follow, and with high levels of performance (development) become carved turns (a.k.a. Refined Skidded Christies).

The carved turn, due to its origins (Slipping skis), will never evolve into an arc. It is predisposed to unending refinement. I look at carving in the same terms as numbers approaching infinity. There is always one more, it can never be reached. It is also like halving the distance between two points again and again and again. The distance shrinks but some amount always remains. The two points never meet.


IMO, Passive rotary= the definition of a passenger not a pilot. That is not for me. The less carved the less stable? using Passive movements most likely will do that. What about wedge turnes? Is the pelvis in a carved turn (I will assume you are talking about arcing now) being turned out as the arc progresses so an increasing amount of counter develops? Not in my world. Counter is established by (gaited movement) of inside half lead prior to and is the cause of (with the addition of other movements) deflection.

Quote:
Observation of this is often miss-perceived as a cause instead of allowed to be an effect. True, if the rotary becomes ‘active’ enough it can become a causing force. But if the passive rotary were blocked and not allowed to happen, the body would always remain in a very square relationship to feet and skis. I think this blocking would also produce more park-n-ride vs. the subtle but rhythmical winding-unwinding seen in expert skiing
This passive rotary term must have been conjured up from passive
observations. Doing it is the problem.
post #129 of 147
"Slipping skis are at an angle to the Direction Of Travel (DOT). Sliding skis are parallel to the DOT. Sliding skis is the innate base of support for arcing. A totally different beast! Both slipping skis and sliding skis leave distinct signature tracks in the snow. Slipping, scrubs a pattern across the DOT. Sliding, presses a track parallel to the DOT."

I love this, I don't know how many times I hear people confuse sliding, slipping, & skidding. Thanks!

"The carved turn, due to its origins (Slipping skis), will never evolve into an arc. It is predisposed to unending refinement. I look at carving in the same terms as numbers approaching infinity. There is always one more, it can never be reached. It is also like halving the distance between two points again and again and again. The distance shrinks but some amount always remains. The two points never meet."

Good on you again! Then how would you define arcing?

Thanks,
JF



post #130 of 147
Quote:
Originally Posted by Bolter View Post
If the rotary movement of the legs (using braquage) meets enough resistance (mired in spring mank) the upper body will counter? I don’t know, is that true?
I don't think so. I think you'll get knee angulation.
post #131 of 147

your answer plus a teaser- become a suppoerting member

Quote:
Originally Posted by 4ster View Post
Good on you again! Then how would you define arcing?
Thanks,
JF
Arc- (n) Is the pattern left in the snow by an edged, de-cambered, sliding ski when the tail is following the tip. This causes deflection and a change of direction (turn).
Linking arced turns (Arc to Arc skiing) is the fulfillment of gliding. It is the essence of skiing. Arcing produces the fastest glide over the snow – with speed control from direction, not friction. This is serious fun and it’s not just for racing. Linking arced turns is achievable by the average skier. You do not have to be a world class athlete to do it.
Arcing is rooted in two principles:1. Sliding/Arcing skis aligned parallel to the Direction Of Travel (DOT) as the innate base of support.2. Stancing Mechanics - four phases of the arc turn
Skis that are arcing have tremendous potential for:Edge grip, Maximum glide & Control of the DOT and momentum, Stability & support for strength and balance
Arcing axiums would include:
The body balances on a foundation of two sliding skis with no static positions.
Arcing skis- the tail should follow the tip and be aligned parallel to the DOT (Direction of Travel). This is true of (both) the inside and outside ski. Speed (momentum) control is accomplished through direction not friction.
The body moves into an inside half lead alignment (PREPARATION) stance to enter the arc. Ankles are dorsi - flexed and optimal outside leg length is established. The upper body alignment mirrors the stance.
The outside ski is engaged by leg (thigh) adduction and the inside ski is engaged by abduction.
Inside leg moves (flexion and extension) parallel to the sagittal/medial plane of the body and perpendicular to the skis top sheet
There should be no sudden raising or lowering of the hips. Movements that create a radical increase or decrease in pressure are avoided and an effort is made to maintain ski/snow contact.
Pivoting or steering the skis should occur only during the PREPARATION PHASE, when the skis are in a low energy state . The skis are energized by physiology and deflection, with force exertion and force resistence parallel to the DOT.
post #132 of 147
Bolter,
That is clear, & consice. To me, this is the essence of modern ski technique.

"The outside ski is engaged by leg (thigh) adduction and the inside ski is engaged by abduction.
Inside leg moves (flexion and extension) parallel to the sagittal/medial plane of the body and perpendicular to the skis top sheet."


What is amazing is how this can be adapted to most, if not all conditions & snow textures.

I am still experimenting...
Thanks,
JF
post #133 of 147
Quote:
Originally Posted by Bolter View Post
Arcing produces the fastest glide over the snow – with speed control from direction, not friction.... Speed (momentum) control is accomplished through direction not friction.
Speed control can only happen through friction. If your skis provided zero friction throughout a turn, your speed at the bottom of the turn would be the same as the speed of a free falling body which had fallen the same vertical distance. Turning increases the force applied by the ski to the snow in proportion to the secant of the edge angle and increases friction losses if the coefficient of friction is constant. Skidding turns a great deal more of the ski's energy into heat or sound than does a carved turn, but any speed control stil has to come from turning the ski and skier's kinetic energy into some other kind of energy.
post #134 of 147

At the risk of introducing some friction to this discussion

Quote:
Originally Posted by FOG View Post
Speed control can only happen through friction. ....
, but any speed control stil has to come from turning the ski and skier's kinetic energy into some other kind of energy.
As the FOG slowly rolls out over the Chesapeake, we can see that speed control can also be achieved by direction most obviously when speed (kinetic energy) is converted to potential energy when one finishes ones turns going uphill. When travelling downhill, the direction one takes effects speed by changing the rate at which potential energy is converted to kinetic energy. You don't have to convert kinetic into potential to control speed, you can simply choose to convert more or less potential into kinetic.

With apologies to Physicsman for practicing Physics without a license.
post #135 of 147
Quote:
Originally Posted by therusty View Post
As the FOG slowly rolls out over the Chesapeake, we can see that speed control can also be achieved by direction most obviously when speed (kinetic energy) is converted to potential energy when one finishes ones turns going uphill. When travelling downhill, the direction one takes effects speed by changing the rate at which potential energy is converted to kinetic energy. You don't have to convert kinetic into potential to control speed, you can simply choose to convert more or less potential into kinetic.

With apologies to Physicsman for practicing Physics without a license.
If all the kinetic energy were converted back to potential energy in turns we would end up at the initial elevation. Turning increases the friction and also increase the length of path over which the friction applies.
post #136 of 147

Friction from FOG that I deserve

Quote:
Originally Posted by FOG View Post
Speed control can only happen through friction. If your skis provided zero friction throughout a turn, your speed at the bottom of the turn would be the same as the speed of a free falling body which had fallen the same vertical distance. Turning increases the force applied by the ski to the snow in proportion to the secant of the edge angle and increases friction losses if the coefficient of friction is constant. Skidding turns a great deal more of the ski's energy into heat or sound than does a carved turn, but any speed control still has to come from turning the ski and skiers kinetic energy into some other kind of energy.
Dang FOG, you are right. Does Epicski have forum readers that know their stuff or what?
Fog, how about that arc2arc skiing is founded on the following: The arc (the tail of the ski following the tip) is the most efficient pattern for the skis to travel for the conservation of momentum. The coefficient of friction in the direction of travel (DOT) is low and potential for lateral coefficient of friction (lateral adhesion) is high. It is effective to establish edge/snow interaction when the direction of the skis is parallel to the DOT. Phew, glad thats over.
My intent is to show that in arc2arc skiing (by definition) the speed control aspects of a skidded turn are not an option. To maximize glide is one of the outstanding aspects of arcing, conservation of momentum is why arced turns are inherently faster in a course than skidded turns (ignoring line and space choices).
So how do you control your descent and speed? I suggest, by turning, redirecting yourself, deflection; in much the same way that you would while shaping your turns (with a degree of skidding involved).
A clear way to observe this is to set a Sl, GS and a SGS set on the same pitch. The number of turns and arc shape characteristics of each discipline have vertical and horizontal gate distance parameters that define each discipline. (Plus other things that are off subject). As a consequence of these restrictions the speed of each event is implied. SL is slower than GS which is slower than SGS and so on.
Can speed control only happen through friction as you stated. I don't think that is entirely correct. In my experience the effect of turning into the fall line has the predictable result of more speed. Turning out of the fall line has a slowing effect. Even in a traverse on skidded or arcing skis if you continue to turn further up the hill you will slow to a stop. Something is going on there between the DOT and the pull of gravity down the hill. Can you delineate that phenomena for me? I don't know how but it must have something to to with your direction of travel. To quote BigE "I may be entirely incorrect." Thanks for your reply, Bolter
post #137 of 147
While my head was buried in the glow from my lap top monitor, the big dogs came out. I LOVE IT!!
post #138 of 147
Quote:
Originally Posted by Bolter View Post
Dang FOG, you are right. Does Epicski have forum readers that know their stuff or what?
Fog, how about that arc2arc skiing is founded on the following: The arc (the tail of the ski following the tip) is the most efficient pattern for the skis to travel for the conservation of momentum. The coefficient of friction in the direction of travel (DOT) is low and potential for lateral coefficient of friction (lateral adhesion) is high. It is effective to establish edge/snow interaction when the direction of the skis is parallel to the DOT. Phew, glad thats over.
My intent is to show that in arc2arc skiing (by definition) the speed control aspects of a skidded turn are not an option. To maximize glide is one of the outstanding aspects of arcing, conservation of momentum is why arced turns are inherently faster in a course than skidded turns (ignoring line and space choices).
So how do you control your descent and speed? I suggest, by turning, redirection yourself, deflection; in much the same way that you would while shaping your turns (with a degree of skidding involved).
A clear way to observe this is to set a Sl, GS and a SGS set on the same pitch. The number of turns and arc shape characteristics of each discipline have vertical and horizontal gate distance parameters that define each discipline. (Plus other things that are off subject). As a consequence of these restrictions the speed of each event is implied. SL is slower than GS which is slower than SGS and so on.
Can speed control only happen through friction as you stated. I don't think that is entirely correct. In my experience the effect of turning into the fall line has the predictable result of more speed. Turning out of the fall line has a slowing effect. Even in a traverse on skidded or arcing skis if you continue to turn further up the hill you will slow to a stop. Something is going on there between the DOT and the pull of gravity down the hill. Can you delineate that phenomena for me? I don't know how but it must have something to to with your direction of travel. To quote BigE "I may be entirely incorrect." Thanks for your reply, Bolter
The skis are generating heat and mechanical energy as they go through the snow. Were we talking about aircraft that would plainlybe called drag. That drag does not diminsh when the skis are turned down the fall line, nor when the skis are turned across the fall line. The difference is the pull of gravity. The closer your direction of travel is to the fall line the greater the acceleration, and the shorter the path to a point of lower potential energy. This gives the friction less time and space to slow the skis for a given vertical displacement. If we were talking about an aircraft we might be talking about increased thrust (ignoring the change in altitude). The integral of the acceleration over a given vertical displacement is identical, so if there were no friction the change in velocity would be identical. What changes is how much friction can be applied over a vertical displacement. Skidding still gives even more friction and more resistance to downhill acceleration. This is why, for those skiers who can accomplish it, even skidding uphill can reduce velocity.
post #139 of 147
Quote:
Originally Posted by FOG View Post
Speed control can only happen through friction.
Note Key Word = ONLY

Quote:
If all the kinetic energy were converted back to potential energy in turns we would end up at the initial elevation. Turning increases the friction and also increase the length of path over which the friction applies.
Note key word = ALL

I was merely documenting how speed control can be accomplished via turning in addition to friction. I did not say ALL the kinetic energy. Can turning possibly decrease friction? What about the points in the turn when edge angles are decreasing? If a ski is skidding, will turning out of the skid reduce friction? Uh oh - it's getting foggy again!
post #140 of 147
Quote:
Originally Posted by therusty View Post
Note Key Word = ONLY
this is unambiguous. If you descend the hill the only thing reducing your speed is friction, which may impart heat or kinetic energy into the materials in contact with the skier and his skis. It may be the friction of the air affeting the skier, or the snow, or rocks, but it is friction nonetheless which does all the slowing once there is a change in elevation. Note: I used the keyword all again.


Quote:
Note key word = ALL

I was merely documenting how speed control can be accomplished via turning in addition to friction. I did not say ALL the kinetic energy. Can turning possibly decrease friction? What about the points in the turn when edge angles are decreasing? If a ski is skidding, will turning out of the skid reduce friction? Uh oh - it's getting foggy again!
Turning can indeed affect friction. If less of the ski is in the snow, there may be less friction, and if ski skids there may be more friction. If you go from a skidded turn to a carved turn, it will feel like you are going faster because you will have reduced the friction. Clear enough to see all the way from Mt. Airy.
post #141 of 147
Interesting discussion, what caught my interest was the part about PSIA striving for non-arcing turns as a goal, rather than a consequence. Speed control through skidding. I also find it interesting the distinction between carving and arcing. The USSA has an opinion about this also on page 43 from their current manual:

Quote:
"Carving by definition for the USST is a form of steering or turning on a semi-engaged edge. The National team staff makes a distinction between carving and arcing, which is a pure carved turn."

"Arcing is a turn on a completely engaged edge, where the tail follows the tip throughout the turn radius. In general terms, it is the fastest and most efficient turn possible"
What I don't understand is what, if anything, that has to do with the thread about PSIA L3 skiing standards? Same with all the physics lessons about potential energy and friction.
post #142 of 147
Quote:
Originally Posted by borntoski683 View Post
Interesting discussion, what caught my interest was the part about PSIA striving for non-arcing turns as a goal, rather than a consequence. Speed control through skidding. I also find it interesting the distinction between carving and arcing. The USSA has an opinion about this also on page 43 from their current manual:



What I don't understand is what, if anything, that has to do with the thread about PSIA L3 skiing standards? Same with all the physics lessons about potential energy and friction.
It appeared to me that the definition of arcing contained incorrect concepts, so I was refuting the apparent misunderstanding. The thread definitely got off topic at that point, although at least we were talking about skiing.
post #143 of 147
Quote:
Originally Posted by FOG View Post
this is unambiguous. If you descend the hill the only thing reducing your speed is friction, ... Clear enough to see all the way from Mt. Airy.
Ah - now with these qualifications, I can agree. My complaints appear to be with a more general interpretation of your remarks than you intended. That helps to clear the Air(y).
post #144 of 147

what if blah blah?

Quote:
Originally Posted by BigE View Post
I don't think so. I think you'll get knee angulation.
Originally Posted by Bolter
If the rotary movement of the legs (using braquage) meets enough resistance (mired in spring mank) the upper body will counter? I don’t know, is that true?
I made (came up with) this question biased on your post #120. It doesn't really matter. I do think that if the upper body is stabilised... oh well. I always look forward to your feedback and posts. Bolter
post #145 of 147

It is my doing, on or off subject

Quote:
Originally Posted by borntoski683 View Post
Interesting discussion, what caught my interest was the part about PSIA striving for non-arcing turns as a goal, rather than a consequence. Speed control through skidding. I also find it interesting the distinction between carving and arcing. The USSA has an opinion about this also on page 43 from their current manual:.
Where, what poast # is the goal/consequence thing?

Quote:
What I don't understand is what, if anything, that has to do with the thread about PSIA L3 skiing standards?
From post #110. The passive rotary and the maneuver discriptions for Level 3. Bob Barnes (as per PM with me) asked that I go public with my comments. This is right on topic, I think. Bolter
post #146 of 147

On subject, passive rotary in L3 maneuvers

Quote:
Originally Posted by BigE View Post
As I see it, gait mechanics is what enables passive rotary to be used to unwind from counter. Outside leg relaxation unblocks the pelvis and allows it to be realigned. The realignment occurs as the body unwinds and the free leg swings by the new stance foot.
Quote:
I don't think mixing gait mechanics with bracquage is possible, because gait mechanics does not use each leg to anchor the other. Gait mechanics certainly have a free/swing leg, and a stance leg, but the swing leg is not anchoring the stance leg.'
__________________
Col Kurtz: "The core..er... the core..er.."

So...
You can mix gait mechanics with passive rotary but you can not mix gait mechanics with braquage, because of the fulcrum aspects (one leg anchoring the other) of braquage. Passive rotary is not a fulcrum mechanism (as I/we understand it) in that it requires rotary movement of the skis (from deflection] to wind-up the legs, but the unwind part is pretty normal. Man oh Man.
Now, I understand that Passive rotary is employed in both the winding into anticipation and its release. This is a versatile mechanism! If it were powerful also and not so passive, we could call it BRAQUAGE!
I think (maybe until I understand more) that using passive rotary is akin to the initial musings of the "pure carve" in ATM. "It exists only in artificial situations and in the minds of superficial ski technicians." Present company excluded. Respectfully yours, Bolter
post #147 of 147
I have to say my post 120 was misleading. The "countering movements" are "counter-acting" movements -- knee angulation with CM sitting vertically above the skis -- showing bases uphill. I screwed up and up-chucked a PMTS term, then wrote it down in shorthand with huge ambiguity. Sorry -- I was less than clear. I have to blame it on the rum.

As I understand bracquage, the rotational axis of each leg is directly beneath the hip socket. If your feet are stuck, then your upper body can't move -- only the knees can move. ( If your upper body moves, then the rotational axis is somewhere else, and that ain't bracquage in the first place. )

Back to reality:

You are very correct. Passive/Active rotary is a HUGE concept. Obviously, active rotary at initiation can mess up the arc through tail displacement.

Active rotary can also (and will also) mess up the arc at redirection through "over-redirection."

Suppose you rotate the femurs into the turn just as you release pressure at completion of the turn. So, you've relaxed BOTH legs, and applied some rotary. The CM continues on it's merry way downhill, and the edges don't fully disengage.... Now, because of the rotation, knee angulation has caused the edge angle to increase. This tightens the turn and brings the skis even more across the fall line.

Now the DOT of the CM and the DOT of the skis are very different. To align their DOT's, you'll have to pivot the skis. Which means, you are not going to come down on the outside edge, and you are not going to have anything whatsoever to do with gait mechanics.

Active rotary at ANY point in the turn means that gait mechanics cannot apply. Jumping mechanics maybe, but not walking.

Moreover, that ain't arc to arc skiing either.

So what broke it? Too much cross-under.

I'll say that the perfect arc-to-arc comes from pure cross-over skiing.
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