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Stacked stance - Page 2

post #31 of 47
Quote:
Originally Posted by BillA View Post
This is a perfect illustration of how the use of jargon or the language of proprietary systems leads to confusion and misunderstanding. Particularly when there is an incomplete understanding of the terms used. Stop using the jargon and this problem will go away.
As far as I know the word 'co-contraction' as used to mean the stabilization of a joint is not PMTS specific jargon.

Quote:
Originally Posted by BigE View Post
Max's definition speaks only about joint stabilization, and nothing of movement...
It's not a definition I created. I will ask a friend that has a degree in exercise physiology if there is something missing.

I don't understand the reasoning for the debate of one word or concept here? To get back to BigE's idea of a stacked stance it would seem that something has to happen to stabilize the ankle, knee, and hip joints as they carry the forces created when making a turn.
post #32 of 47
Bill, do you think its easier to manage the forces of a carve with an extended outside leg for a flexed outside leg?
post #33 of 47
Quote:
Originally Posted by Max_501 View Post
Bill, do you think its easier to manage the forces of a carve with an extended outside leg for a flexed outside leg?
An extended leg uses the skeleton for support, a flexed leg uses the muscles for support.
post #34 of 47
Thread Starter 
Yes Bill, post 28 does make sense-- and it points out the excess baggage we carry around with our choice of words.

I'd say that "Joints are flexed, weight centered, muscles relaxed and poised to react" is being stacked. The tennis player can relax his muscles more, since there are no external forces acting on them , they are just upright and "ready". But notice what happens at the moment the opponent serves the ball. The player, once rocking from side to side experiences a general stiffening and the rocking momentarily stops -- co-contraction! The CM stabilizes over the feet and can be moved in any direction.

The notion that co-contraction stabilizes the joint makes it sound like you should be a statue. However, co-contraction also occurs when making fine adjustments -- eg. like when threading a needle, your hands and fingers do more than just push - they aim. They stabilize the thread and needle as you can move the hole of the needle overtop of the stationary thread. So, co-contraction does is make movements themselves very accurate. How?

Let's get back to skiing, where co-contraction will assist in accurately bringing the feet under the CM or, the CM over the feet. (Do you move the thread or the needle?)

I think we all notice some increased tension within our bodies when we ski on very stiff skis. That can be attributed to co-contraction trying to keep us in the sweet-spot. This is no different than the "relaxed and ready" tennis player moments before impact of the serve. To my mind co-contraction resists overshoot, and transmits movements at the feet to higher joints in the body, which enhances proprioception. This has an immediate effect on your automatic balancing moves, as a result your balance improves.

Another cheesy example.... In a deli you pickup a piece of cheese. How heavy is it? Do you hold the cheese motionless at the end of a very tense arm, or do you hold it gently, moving it up and down?

In the motionless case, you can tense so much that the weight virtually disappears -- you've short-circuited your proprioceptive system.

In the more gentley held (dare I say "relaxed"?) case you're creating a functional tension that allows you to sense the weight of the cheese more accurately. In comparison to full-on arm locked tension, the more "relaxed" case does have some tension. It was created by co-contraction.

Ever hear the direction to "activate the core" when skiing? Abs and back pulling against each other? That's co-contraction. It lets you accurately detect and react to movements in the spine/hips.

At least, that's how I understand it to work. So to me, "stacked" is equivalent to :

"Joints are flexed, weight centered, muscles relaxed and poised to react."

When "muscles relaxed and poised to react" means "muscles in a state of functional tension". The method to develop that "functional tension" is "co-contraction".

Does that all make sense?
post #35 of 47
In a balanced stacked stance there is a balance between strength of aim and relaxation. To much co-contraction slows down the movement, not enough and the movement is uncoordinated, unmanaged, and imprecise.
post #36 of 47
Quote:
Originally Posted by BigE
Does that all make sense?
Yes it does, thanks for the explanation. I think we are in agreement on the rest of it.
post #37 of 47
Quote:
Originally Posted by BillA View Post
This is a perfect illustration of how the use of jargon or the language of proprietary systems leads to confusion and misunderstanding. Particularly when there is an incomplete understanding of the terms used. Stop using the jargon and this problem will go away.
Quote:
Originally Posted by Max_501 View Post
As far as I know the word 'co-contraction' as used to mean the stabilization of a joint is not PMTS specific jargon.
Look at the use of co-contraction from a clip of an article I found:

Quote:
In each situation, responses were consistent within individuals or repeated efforts. Electromyographic variability occurred in the magnitude of responses across individuals. Co-contraction in this instance refers to the presence of simultaneous activity in opposing muscles and does not depend on latency or timing (not measured in this study). Consequently, these measurements examine the overall activity, not the sequencing of activity.

The effect of co-contraction on movement is controversial. Under normal circumstances, co-contraction provides the joint with greater stability, especially when distal limb segments are free to move.
Now compare that to the definition I was taught:

Quote:
Originally Posted by Max_501 View Post
Opposing groups of muscles working together to stabilize a joint.
Perhaps what I was taught is over simplified but it seems to capture the gist of it.
post #38 of 47
How is it possible to flex a joint while on skis and have your muscles relaxed?

Even sitting in my chair right now, flexing my ankle or knees requires the muscles to tighten to cause the flex.

So,
"Joints are flexed, weight centered, muscles relaxed and poised to react."

can't be possible.
post #39 of 47
Quote:
Originally Posted by BillA View Post
An extended leg uses the skeleton for support, a flexed leg uses the muscles for support.
I don't think this fully answers the question. An extended leg is able to support a larger load and with less effort, ergo we walk by swinging extended legs. However, as the surface becomes more bumpy it becomes rather obviously more efficient to flex the knee instead of the waist. The further we flex the leg the less load it can support. We search for an optimum mix of extension and flexion that allows us to react to the surface just adequately while maintaining as much extension as we can because our biggest muscles have more leverage wrt the load there.
Your statue like static definition of "stacked" doesn't resonate for me the way Ghost's definition of a position that requires minimal energy for the task does. Support the load without becoming a statue.

And I agree with Lars that you can't be standing on skis with relaxed muscles, but I think the key is that you can be in a state of relative relaxation compared to a skier way out of balance.
post #40 of 47
Quote:
Originally Posted by skiingman View Post
I don't think this fully answers the question. An extended leg is able to support a larger load and with less effort, ergo we walk by swinging extended legs. However, as the surface becomes more bumpy it becomes rather obviously more efficient to flex the knee instead of the waist. The further we flex the leg the less load it can support. We search for an optimum mix of extension and flexion that allows us to react to the surface just adequately while maintaining as much extension as we can because our biggest muscles have more leverage wrt the load there.
Your statue like static definition of "stacked" doesn't resonate for me the way Ghost's definition of a position that requires minimal energy for the task does. Support the load without becoming a statue.

And I agree with Lars that you can't be standing on skis with relaxed muscles, but I think the key is that you can be in a state of relative relaxation compared to a skier way out of balance.
Good post skiingman, I agree. This is evident when skiing moguls all day. Good mogul technique requires much less energy than poor technique. Thus finding the right flex and posture is so important in relation to the quality of the turns you put down. Same thing in powder. Those of you who get early thigh burn while skiing powder and bumps are not in a balance position where the stance, flex and right amount of muscle relaxation is the key to how long you last the day. Conditioning does come into play also. some people just aren't in good enough condition to get into this position or stay in it for any length of time. Everything breaks down.
post #41 of 47
How about the term "functional tension" for being physically ready to act? The body is primed for movement, supple and without stiffness.

Are you guys looking for just the right words to describe a functional stance for skiing? Unless you are writing a book, I submit the body already knows--the only danger is in overcomplicating it.
post #42 of 47
So, what's your point?

Gotta have something to talk about don't we?
post #43 of 47
I see two things here. One is the alignment of the bones, i.e. straighter legs bear weight easier. That's what most people mean by a "stacked stance". The other is more elusive, and has to do with being relaxed enough to let the movements "flow" through you without impedement and using correct muscle recruitment to stabilize joints and maintain precision.
post #44 of 47
Quote:
Originally Posted by nolo View Post

Are you guys looking for just the right words to describe a functional stance for skiing? Unless you are writing a book, I submit the body already knows--the only danger is in overcomplicating it.
Wisdom!
post #45 of 47
Quote:
Originally Posted by nolo View Post
How about the term "functional tension" for being physically ready to act? The body is primed for movement, supple and without stiffness.

Are you guys looking for just the right words to describe a functional stance for skiing? Unless you are writing a book, I submit the body already knows--the only danger is in overcomplicating it.
Hi Nolo,

1) I would agree that the words are not all that important but the concepts are. Having the right "functional tension" that stabilizes joints and permits smooth activation and movement still doesn't bring in a concept that I think "stacked" seems to include. That concept is the alignment of joints and body parts (with functional tension) in reference to the outside world to promote effective dynamic balance and movement.

2) I think that the "body" may be able to recognize a stance that is more functional than another but that doesn't mean it readily knows how to create that, especially with the perceptual challenges (fear of speed, fear of falling, etc.) that skiing brings to the equation. No need to make it complicated but I think Big E was originally asking about how to help the body create a more functional stance that then can be recognized and incorporated into one's skiing.
post #46 of 47
Thread Starter 
Thanks Si:

Quote:
Originally Posted by BigE View Post
So what cues do you use to teach people to 'get stacked'?
post #47 of 47
FWIW,

You can define things how you like....but to me stacked has really referred to the lateral alingment of the joints....ie no A-Frames....a good analogy that I use is doing Squats at the gym.....feet a functional width, knees over feet, hips alinged with knees (not necessarily "above"), spine straight, shoulders square to spine.....but you obviously still have a full range of motion....but that is the strongest biomechanical position to be in...and the "plane" that is created by this "stacked stance" is the most stable with which to move along....if you look at being stacked as just a fore/aft thing, I think you will find it confuses people...hence posts #2 to #43 in this thread.
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