or Connect
New Posts  All Forums:Forum Nav:

The Quality of Movements

post #1 of 26
Thread Starter 
An offshoot of the Rotary Thing thread.

In all the talk of rotary movements in the previous thread, I did not notice any mention of reverse rotary movements, or what I call backspin. If you notice how you steer your car in a turn, often not all the rotation of the steering wheel is turnward, but some is rotation opposite the turn, which fine-tunes direction.

There were a few years in the '90s where "directional movements" were part of the PSIA skills concept, but direction (where movements are targeted) is now considered a quality of movement, along with duration, intensity, rate, timing, and origin in the body. A skier changes the quality of the same basic movements to achieve his/her tactical objectives.

From the PSIA Alpine Technical Manual, p. 9:

Quote:
Skiing has a simple formula: 1) stay in balance while moving; 2) tip certain body parts to edge the skis; 3) rotate the back, hips, legs, and/or feet to help turn the skis; 4) control pressure along the skis to shape the turn and handle changes in terrain and snow conditions.
According to PSIA, skill in skiing is having a functional blend of rotary movements with edging and pressure control movements to achieve the tactical objective or purpose the skier has in mind. Skills blending is a matter of adjusting duration (how long or short), intensity (how powerful or forceful), rate (speed), timing (when you do it), origin (kinetic chain), and direction (going there).

Is this concept good, bad, or irrelevant?
post #2 of 26
Here I am just sporadically jumping into this forum again.

Anyways, Nolo, what you are describing is something I have
wondered about in the past.

The National Motorcycle Safety Foundation teaches all new
riders a very essential biking concept called "counter steering". If you want the bike to go left, steer right. Sounds a little crazy until you try it, but it really works.
For you non-believers, get your bicycle up to speed, then pull
on the right handle-bar grip. The bike will dive to the left.

I've always suspect that similar physics must be at work with my
skiis?

[ July 17, 2003, 03:26 PM: Message edited by: Sitzmark ]
post #3 of 26
sitzmark, unless you have a big gyroscope spinning in your belly, the physics aren't the same.
post #4 of 26
Surely any force application such as rotational movements must be applied in opposition to some other force. The skill we gain as we experience this muscular tension between opposing forces is a controlling skill. A lot of the confusion arising from so-called "rotary" movements arises from the differing ways in which this controlling force is employed in different levels of skiing. In the lowest levels of skiing when we introduce these movements this is typically a gross,application of force to actually turn the skis. This is appropriate at this level because the skier needs to be able to turn the skis in order to manage speed and lacks the sophisticated blend of skills employed to turn the skis in more advanced skiing. As the skier progresses, other skill developments are blended to produce turns, The rotational skills employed are less the actuator of turning and to a greater degree involved in controlling the relationship of the legs and skis to the upper body. At the very highest levels of skiing technique such as World Cup racing you will see the skis change direction while the upper body remains facing down the hill to some degree, ie. countered. Leg rotation is ocurring, although it may not actually be used to turn the skis directly. Turning the skis directly in this scenario is virtually imposible through much of the turn simply because the skis are so deeply edged. Turning of the skis with leg rotation during the phase of the turn in which the World Cup skier's skis are not highly edged is not normally desired because of the increase in friction which results. Nowadays, because of changes in equipment, this kind of turning of the skis is not usually necessary. The leg rotation which is ocurring enables the racer to develop a countered stance which, in turn, enables angulation to occur by bending at the waist (you really can't bend very muct laterally at the waist, the body just isn't made that way. Most of the angulation you see in advanced skiers is a result of bending forward at the waist, converted into a lateral angle because the torso is countered with respect to the skis) Angulation is primarily a balancing device to enable effective edge angle, thus rotational movements do play a critical role in turning the skis. They just are not applied directly to the skis. The controlling skill we develop in the varied application of leg rotation in traversing the gamut from level one to World Cup racing is one of the principal means we have of gauging feedback from and managing the relationship of the torso to the forces we experience resulting from turning and we use this to direct balancing movements.

End of rant.
post #5 of 26
I use my inside foot/tib/fib in a manner akin to the rudder of an airplane to control direction. I use inclination/angulation like ailerons. I am less focused on pressure in an effort to not stand against or "brace" against the outside ski.
post #6 of 26
Rusty
The rudder is quite effective at causing change of directioin at very low speed, such as when taxi-ing on the runway but, while flying, the ailerons are used to change direction.
post #7 of 26
That brings to mind another possible flying-skiing analogy. Would intentional crabbing while flying (ie, using the rudder excessively without corresponding movements of the ailerons) be analogous to introducing some skid into a carve? Both actions could have some pretty unwanted results if done to excess and/or at too high a speed.

Tom / PM
post #8 of 26
Quote:
Originally posted by arcadie:

Entire post above. (On the evolution of rotary application during skill development.)

[/QB]
Well done arcadie!

Couldn't find just one section to quote because I liked the whole post. Good work! [img]graemlins/thumbsup.gif[/img]

[ July 18, 2003, 05:16 AM: Message edited by: FastMan ]
post #9 of 26
I can pull out of the new or old PSIA manuals many short paragraphs or sentences that support or do not support skiing, as you and I may understand it. Simply skiing is going down hill and turning your skis. The more turning you do the more or less counter we create due to our natural body shape/size. Pressure happens due to again the shape/size of the turn and the skier. Efficiency is something the instructor can assist the student with. We do not need to make skiing complicated or “mystic”. The very best instructors I have worked with take the student, shape, size, & ability, and adapt the lesson accordingly. I know many hate the simplification of skiing to “go down hill and turn your feet” but it is truly not as complicated as we make it. Therefore why do we transfer this to our students? Truly it really confuses the student and us!
post #10 of 26
Arcadie,

A post well done. Very easy to understand your contention. It seems to me the "model" you propose is saying that rotational leg movements become tools mostly for balance and "angulation" as a person's skiing level advances. Rusty's comment implies to me that he doesn't necessarily share this model but one where rotational leg movements more directly control the direction the skis are pointing. My own perceptions fit more with your model but I am interested to hear from others (if indeed I've got the "models" right). Of course I can also see where the difference between these two points of view could be solely a matter of perception and in fact both might be used to describe the exact same situation.

Of course with proper intrumentation and experimentation we could readily determine how much torque (to twist the ski in the plane of the snow) is being applied to the ski from the boot in various situations by different skiers.
post #11 of 26
Great post arcadie. [img]graemlins/thumbsup.gif[/img]
It goes back to a person's definition of "rotary". If you're talking about turning the skis, or, rotary movements of the skier.

Question to the pilots.(I've been an airplane enthusiast most of my life but never tried to fly one) In an aileron turn, isn't it necessary to "counter" slightly with the rudder to maintain altitude? I read in Time magazine that it was thought that this is why JFK Jr. went down.
post #12 of 26
> ...Question to the pilots.(I've been an airplane enthusiast most of my life but
> never tried to fly one) In an aileron turn, isn't it necessary to "counter" slightly
> with the rudder to maintain altitude?

From this web page , under "Turns":

To enter a turn, you should simultaneously turn the control wheel (i.e., apply aileron control pressure) and rudder pressure in the desired direction. ... The speed (or rate) at which your airplane rolls into a bank depends on the rate and amount of control pressure you apply. ... The amount of bank depends on how long you keep the ailerons deflected.

Rudder pressure must be enough to keep the ball of the inclinometer (part of the turn coordinator) centred. ... If the ball is not centred, step on the ball to recentre. EXAMPLE: If the ball is to the right, apply right rudder pressure (i.e., step on the ball) to recentre. ...The lift produced by the wings is used to turn the airplane, as discussed in "How Airplanes Turn"

To maintain a constant altitude, you will need to apply enough back elevator pressure (raise the nose of the airplane) to maintain constant altitude.

As the desired angle of bank is established, aileron and rudder pressures should be released. The bank will not continue to increase since the aileron control surfaces will be neutral in their streamlined position.

The back elevator pressure should not be released but should be held constant or sometimes increased to maintain a constant altitude.


Using the elevator (ie, not rudder) to maintain altitude is SOP for "normal" turns (ie, under 30-45 deg). The rudder is used mostly to keep it in a minimum drag attitude (ie, not crabbing its way through the turn). Although I couldn't immediately find a reference, in extremely steeply banked (ie, acrobatic) turns, you may have to do what you said, but there is a lot of other stuff also going on simultaneously that must also be dealt with, and using "reverse rudder" (ie, like "reverse shoulder") is not the norm for turns in ordinary flight.

For the record, I'm not a pilot either, but about 1/4 of my work towards a Ph.D., and about my first 8 years of work after the Ph.D. was in aerodynamics (albeit internal, not external flows).

HTH,

Tom / PM

PS (in edit) - The following passage from http://www.skysailing.com/pages/theory.htm may be of interest in that it discusses crossed controls in gliders:
"Crossed controls" is a heinous sin in powered flight. It should be noted that the same undesired effects of a turn are in a powered aircraft, but are most noticed when in slow flight or steep turns. Most of these effects are more noticeable in the sailplane because of our long wings and slower speeds. ...

PS#2 - Sorry about the interruption. If the flying discussion goes on for more than another post or two, we'll start another thread for it.

[ July 28, 2003, 07:05 PM: Message edited by: PhysicsMan ]
post #13 of 26
Asked a level II cert and United captain (Bob Booker from Loveland) who said "the smaller the aircraft, the more the need for rudder". He did say the use of any rudder in any turn is very slight.
post #14 of 26
Quote:
Originally posted by Si:
Of course I can also see where the difference between these two points of view could be solely a matter of perception and in fact both might be used to describe the exact same situation.

Of course with proper intrumentation and experimentation we could readily determine how much torque (to twist the ski in the plane of the snow) is being applied to the ski from the boot in various situations by different skiers.[/QB]
Si
I think you're probably correct that these differing points of view are apt to reflect a difference of perception but I think it is important that we clarify our understanding since we often teach from our understanding, even when it, seemingly, comflicts with our actual experience.

It would be great to be able to document these forces with instrumentation. I've often wondered how much rotary force applied to an edged ski could be affecting the turn. You would think the amount of such force that could be applied to an essentially immovable object that the edged ski is would be limited, I mean how strong is the knee joint anyway? The product could be some stored muscle tension (torque)that would have its release as the ski is flattened but what would that achieve? I can see how the application of rotational force to edged skis early in the turn could tend to "lock" them in before the fall line when pressure against the ski would otherwise be limited. I have tried this myself but wondered if I was doing my knees any harm. It is one way, along with early cross-over and edging to achieve an early, comma shaped turn, but I don't know if this is a component of what the racers are doing.
post #15 of 26
Arcadie, again a well stated comment on "rotary." The only thing I might add is that from what I've garnered from other's posts here (and my own experience) the root of this rotational force in the plane of the ski (I think that's more accurate than the plane of the snow) is mostly from hip rotation (of the femur within the acetabulum) not the knees. Some of this happens automatically when supinating and trying to purely tip the ski. To be clear, I think we (and hopefully others) are both talking about the application of torque beyond this point.
post #16 of 26
Thread Starter 
Quote:
Surely any force application such as rotational movements must be applied in opposition to some other force. The skill we gain as we experience this muscular tension between opposing forces is a controlling skill. A lot of the confusion arising from so-called "rotary" movements arises from the differing ways in which this controlling force is employed in different levels of skiing.
Arcadie, I'd like to join the others in congratulating you on your post. The word "control" in PSIA's skills concept is meant precisely as you described.

I'd like to reiterate:

Quote:
A skier changes the quality of the same basic movements to achieve his/her tactical objectives.
What can get lost in our overly technical analyses (to some people) is the simplicity of this principle and the infinity of movement options it opens up to us. As you assess different schools of thought on skiing, worry about versatility and adaptability. The objective of any credible skier development program is to develop a solid foundation of basic movements which can adapt to any situation. Anyone who would suggest otherwise (e.g., by ostentatiously discarding a whole class of fundamental movements) is flat wrong, in my opinion.

[ July 30, 2003, 06:32 AM: Message edited by: nolo ]
post #17 of 26
[quote]Originally posted by nolo:
Quote:
As you assess different schools of thought on skiing, worry about versatility and adaptability. The objective of any credible skier development program is to develop a solid foundation of basic movements which can adapt to any situation. Anyone who would suggest otherwise (e.g., by ostentatiously discarding a whole class of fundamental movements) is flat wrong, in my opinion.
Very nice Nolo, one of the most insightful statements I've read on this forum. It puts a proper perspective on much of the silly debate that occurs here. Your paragraph should hang on the wall of every ski school and race program in the country, and should be tattooed on the back of the hand of every teaching professional. [img]graemlins/thumbsup.gif[/img]
post #18 of 26
I'll second that.
post #19 of 26
Thread Starter 
Thank you. :
post #20 of 26
Quote:
Originally posted by nolo:
What can get lost in our overly technical analyses (to some people) is the simplicity of this principle and the infinity of movement options it opens up to us. As you assess different schools of thought on skiing, worry about versatility and adaptability. The objective of any credible skier development program is to develop a solid foundation of basic movements which can adapt to any situation. Anyone who would suggest otherwise (e.g., by ostentatiously discarding a whole class of fundamental movements) is flat wrong, in my opinion.
Sounds like a bit of "apple pie" - I doubt that anyone would disagree. From what I can discern, however, the biggest difference between various approaches, instructors, and coaches is in HOW they work to develop a solid foundation of basic movements. In skiing (as in many other sports) it may be best to focus on different movements at different stages of development and just as importantly to avoid certain movements at certain stages of development. Thus, I would be just as worried about a teaching program, instructor, or coach who couldn't differentiate between appropriate (vs. less productive) movements for a given stage of development (and indiviual skier characteristics of course) as anything else.
post #21 of 26
Maybe I`m missing something , but the creation of basic skills is necessary in order to set the scene for the movement pattern to occur spontaniously , thus giving the class the opportunity and pleasure of self discovery. Essentially, very little needs to be said . Perhaps this is a bit outside of this discussion but it seems to me to have validity. We are blending skills and patterns together to produce a result.

[ August 05, 2003, 07:40 AM: Message edited by: Larry C ]
post #22 of 26
Thread Starter 
Quote:
the biggest difference between various approaches, instructors, and coaches is in HOW they work to develop a solid foundation of basic movements
Very interesting, Si. Are you saying that we will find the most significant differences between schools of skiing not in their technical fundamentals but in their teaching methods? Are you saying that among ski professionals and pro-level amateurs, there are significant disagreements about the HOW, but general agreement about the WHAT?

There's not much evidence of that on these forums, where Technique gets far more words thrown at it than Instruction, but it's a very interesting idea.
post #23 of 26
Nolo, I guess in my interpretation I see lots of evidence for this. I see a high level of (not total) agreement about "quality" anytime some good skiing is displayed on video here at Epic or implied via a photo. What I see much more of is disagreement between individual perceptions about what one does to generate such movements or even how to describe them. (One person's wide stance is another's narrow). Another confounding point is when one person talks about approaches to learning such movements, with a certain level of skiing ability in mind, and another disagrees with the first by pointing out all the things that particular approach leaves out.

This certainly leads to an appearance of great differences in people's descriptions of what good skiing movement patterns are. However, I doubt that there would be much disagreement about the overall quality of a high level skier's peformance. There may be differences between skiers skiing as such levels (and differences of opinion about what they are doing) but all of them widely share the ability to dynamically respond to varying situations using a variety of movement patterns. I think that's the "apple pie" of it.

[ August 05, 2003, 11:11 AM: Message edited by: Si ]
post #24 of 26
Quote:
Originally posted by Si:
...However, I doubt that there would be much disagreement about the overall quality of a high level skier's peformance...
Say, aren't those Amazon natives I hear in the distance? [img]graemlins/evilgrin.gif[/img]

Tom / PM

PS - Hey Si, aren't/weren't you supposed to be heading out to this neck of the woods sometime soon?
post #25 of 26
Si, I definitely don't see Nolo's comment as a feel good "apple pie" statement designed to leave little room for disagreement. In fact there has been countless examples of antithesis thinking displayed in the debates that have continually raged in this forum. Every time someone attempts to promote one technical model as the exclusive holder of the "correct" title they immediately announce their ignorance to the world, and I've seen enough such announcements made here to find Nolo's sentiment very refreshing and impressive.

Expert skiing is not achieved by focusing on and perfecting one specific movement sequence. Doing so will produce a skier with a very narrow skill foundation who can't readily adapt and improvise. The profoundness of Nolo's statement is in her recognition of this very crucial element of skier development that escapes the understanding of so many ski pros.

To truly achieve mastery of this sport the versatility and adaptability Nolo speaks about must be developed, and this is done by broadening the skill/balance/movement foundation as early as possible in the learning process. Too much teaching methodology is attempting to rapid fire the student to harness a narrowly focused movement sequence, the evidence of which can be clearly found within many of the posts on this site.

Great skiers can execute a gross repertoire of movements, some which even considered improper or inefficient, and make them look beautiful. This is the essence of expert skiing, and it doesn't happen by magic.
post #26 of 26
Fastman,
I guess we just disagree. Versatility with an array of skills are the hallmark of expert performance in any sport - it is "apple pie". The question in skiing, from my point of view, is how best to develop these.

I would think I might be considered as one who believes in focusing on a limited set of movements, although I don't think this is the case. I believe in a very strong focus on tipping (vs. pivoting/steering) and balance. However, as improved control and balance are achieved I have found it opens the doors to so much more both for myself and others. I may talk about a focus on tipping but I also readily say that I regularly use pivoting in my skiing. I could talk about the relationship of other skiing movements in a similar fashion (i.e. leg retraction vs. "up-unweighting"). Note that I say these things from a personal perspective as a non-professional and non-expert skier.

I think it's great that Nolo brought up this reminder; it is something that we should always have in mind. I often have similar thoughts when I read some of the posts in this forum and find it critical to put things in proper persepective. I certainly would hope that others would interpret it in a similar fashion, not as a novel idea to be debated. Perhaps I'm wrong, though, and there are many people who would question her statement. I hope not.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Ski Instruction & Coaching