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Which foot to pull back? - Page 3

post #61 of 167
Quote:
Originally Posted by RicB View Post
Max, can we have pressure without weight?
Quote:
Originally Posted by Max_501 View Post
...if the inside ski is lifted from the tail such that the tip is on the snow and then the ski is pulled back that tip will engage more and I'll feel the increased pressure as the ski arcs across the slope.
Quote:
Originally Posted by RicB View Post
So does the tip engaging "create" the pressure you feel or does the pull back put the pressure on the tip that engages the tip? No matter which way you prefer, is either scenario achievable with zero body weight on the skis?
To be honest, I'm not sure that either scenario makes one bit of difference if you are properly balanced with the outside ski.
post #62 of 167
Quote:
Originally Posted by mkevenson View Post
Assuming that one wants to be centered over the ski with hips, ankles and knees generally lined up,(stacked), I have been taught and read 2 distincly different methods. One is to pull the inside foot (ski) back as the turn progresses and one is to pull the outside (downhill) foot (ski) back and extend the inside or uphill ski into the turn(tip lead). I have also read as I reviewd this topic that one should pull both feet back while in the turn. Is there a generally accepted method of keeping stacked over the skis during the turn? Is this method terrain related?
Although I haven't had anyone advocate "extra" tip lead with the old inside ski just as it becomes the outside ski (the second method mentioned), the discussion in this thread should suggest to you that there are several ways to view the first method you suggested. Some revolve around the concept of pulling one or both feet back, which may or may not be necessary, depending on many variables. Others involve moving the CoM forward at the appropriate and effective time. Again, whether this action is actually necessary depends on a number of variables. Depending on perspective and circumstances, any of the methods/focuses may be effective. Or not.

What they all share is that they are all approaches to, as you say, remaining stacked over the skis during the turn, and they all work to control the relationship between the base of support and the center of mass.

Quote:
Originally Posted by justanotherskipro View Post
Pierre,
If you don't retard the inertial momentum in the first place the core is not going to fall back. Dropping the tips and extending into the trough does not require pulling the feet back. The "pull the feet back" move is a correction movement not a tactical solution for bumps. The reason the hips get so far back in the first place is that the core's inertial momentum has been interrupted. Usually by a strong edge set (check) on the top of the mogul, or the feet are pushed forward (and to an edge) as the mogul top is being absorbed. If the core continues to move through this phase, the feet remain more beneath the hips as we crest the mogul. Watch the best mogul skiers and you will see the sit up / and full extending move which uses a large amount of hip flex / extention.
Route is still the most effective way to control our speed, even if we ski the zipperline. Checking and rotory push off moves are not as effective because balancing and momentum are not maintained.
I agree with this, except that I would note that many of us (that would include me) are perfectly capable of reacting ineffectively to some aspect of the terrain or conditions or turn forces and ending up behind our feet. We may accomplish this without interrupting the momentum of our core simply by pushing one or both feet forward too far at the wrong time. This imbalance will certainly be followed, and quickly, by an interruption in the core momentum unless we correct for the error effectively.

I would suggest that any focus that effectively readjusts the relationship between the CoM and the base of support to move toward, or through, balance must be regarded as successful. For that turn. The key word is "effectively" and the next turn will be different. Count on it.

Quote:
Originally Posted by RicB View Post
An argument could be made that "Dropping the tips and extending into the trough" is pulling the feet back. A strong extension will do just that, pull the feet back under the hips after they get ahead from leg flexion. It is not hard to see how in dynamic terrain such as bumps, the feet need to travel farther, and at different speeds than the core/trunk during a turn and as such the feet will slow up at the start and speed up through the turn. In other words, the feet may need to move ahead of the hips, and then move back under the hips. The ever changing force line in uneven changing terrain.
This is true even in nice carved turns on groomed terrain, especially if the skier uses retraction through the transition. An exaggerated retraction very obviously places the hips behind the feet, and the following extension to "long and strong" as the feet move away from the body and skis arc toward the fall line brings the feet back under the hips - or the hips back over the feet, albeit with a necessary lateral component to balance against the turning forces.

Although I tend to use the "elevate the toes/pull the feet back" focus myself, I find an active movement of the CoM in the direction the skis are traveling to be highly effective also. Depending on circumstances.

Ideally, I can manage the momentum of my CoM and the ongoing development of forces at my feet so that I don't have to do either one. I can allow momentum to pull my CoM forward relative to my feet at the same time as my skis are turning out of the fall line to an angle that is less steep, or up the back of bump, or both, and are thus slowing down relative to the fall line. Or, for a different kind of turn with different timing, the extension into the turn rearranges my body geometry so that my hips are once again over my feet. Did I pull one or both feet back, or did I move my CoM forward? Or was it a result of the management of the forces, turn shape, terrain shape, etc.?

I would suggest that it is probably more efficient to apply fundamental skills controlling the interaction of the skis and the snow to alter both the speed and the direction of travel of the feet rather than the CoM. It is my belief that we want the CoM to flow smoothly down the hill while the feet speed up, slow down, move to the side, tip, arc, etc. While a focus of moving the CoM forward is often useful, physics dictates that the feet will slow down more than the CoM speeds up, simply because the body has more inertia than the feet.

Quote:
Originally Posted by RicB View Post
Skiing off a bump and into a trough will require the feet to slow down if the skis are to maintain with the terrain as it drops away. The hips are moving in a straight line while the skis need to change their orientation quickly to match the rapid increase in the slope. Just pushing the toes down won't get the skis down on the snow unless the feet are slowed down and brought back under the hips. Our boot geometry requires this for the ski tips to be engaged. For me this requires firing of the glutes and hamstrings, slowing down the feet, drawing the feet back under the hips earlier or with more focus than a simple extension of the ankles knees and hips. In other words the extensions may not happen simultaneously in all three lower joints.
I've added the underline and boldface. As BB's simplified animation shows, you want the CoM to be over the feet by the time you reach the high point or the transition point. Do you do this by pulling the feet back, or simply by not interfering with the CoM so that it catches up? Your choice - it depends on the turn, the bump, the intent.

Quote:
Originally Posted by RicB View Post
A skier can also huck the CoM up and over the bump as well but then we are adding acceleration to the CoM beyond what gravity is providing. We are adding extra energy.
And it would be more difficult, since the body weighs so much more than the feet.

Quote:
Originally Posted by RicB View Post
In the end I may tell one person to pull their feet back at some point, another to slow their feet down at some point, and another to drive their toes and tips down onto the snow, and they may all achieve the same outcome. So I would personally be carefull using such a broad brush to paint the concept of pulling the feet back as always being a compensatory move. In bumps it can very well be the most efficient and effective move. Steeps as well.
Quote:
Originally Posted by justanotherskipro View Post
Not so RicB. Allowing the body to move over the terrain does not require us to interrupt it's downhill flow. The hallmark of good bump skiers is the uninterrupted movement of the body down the hill.
I don't think RicB implied that the downhill flow of the CoM was being interrupted. Any number of things can cause the CoM to get behind the feet - many of them perfectly legitimate. I think he was merely suggesting a focus on slowing the feet down using any of a veriety of mechanisms to allow the CoM to catch up.

Quote:
Originally Posted by justanotherskipro View Post
Insofar as the skis accelerating because the slope is suddenly steeper, I would say if the skis is being actively worked at that point the acceleration is mitigated and if it doesn't happen in the first place, we do not need to throw in a corrective movement.

In other words If we are centered (everything moving in the same timeline) we can access any combination of the three skills at will, in any terrain.
True - but to actively work the skis on the downhill side of the bump, we need to be centered, as you say. A recentering move, if any, needs to happen before the skis start their inevitable trip down the steep face, or they will accelerate and we'll be even farther behind. Attempting to throw in late corrective movements may be better than nothing, but will be far less effective than arriving at the transition centered.

Getting centered can occur "naturally" - that is, if all is sunny and bright and we are skiing perfectly, the CoM flows, our feet slow down for one reason or another (or never got ahead in the first place), and we end up centered before transition with very little thought or effort. Great.

Getting centered can occur because we use some focus (pull the inside foot back, pull both feet back, move the belly button forward, etc.) and some conscious muscular effort to recenter, if necessary. Different thought processes work for different people at different times.

I personally find that I use the idea of moving the CoM forward (even though I am, in fact, slowing my feet down by some method rather than accelerating the CoM) in some cases, especially situations where I want to extend or get "taller" or "longer." I also use the idea of pulling my feet back, or just pull my less weighted inside foot back (which is easier), especially when I'm using retractions for any number of reasons. The choice is situational, and your mileage may vary.

I do not ever seek to push the inside ski forward and increase tip lead.
post #63 of 167
Quote:
Originally Posted by RicB View Post
No matter which way you prefer, is either scenario achievable with zero body weight on the skis?
Of course not, but pulling the inside leg back doesn't need to add any appreciable weight to the inside ski (it can be lifted) yet it does help with the relationship between the feet and the hips.
post #64 of 167
Quote:
Originally Posted by HeluvaSkier View Post
To be honest, I'm not sure that either scenario makes one bit of difference if you are properly balanced with the outside ski.
I agree Greg. But then I'm not the one who said that we could increase pressure without increasing weight. For me the distinction lies in how we do it.
post #65 of 167
Quote:
Originally Posted by RicB View Post
I can't see eccentric movement (contration) ever pushing anything. I do eccentric movement (contraction) allowing things to happen though, and it is a big part of skiing movement as we manage the forces and use them to our advantage. Otherwise movement requires a motive force from our muscles which is a concentric movement (contraction) of the muscles.
With all respect- assuming that by
"contration" you mean contraction,
you've got it backward
.
Eccentric movement is extension, not contraction.
Eccentric movement does push things....almost exclusively. think of a bench press, or a ski as we extend our leg.
Bear in mind that eccentric movement is as much a part of skiing as concentric movement, as:

A. The return to neutral stance, from either, entails the employment of the oppsosite force

B. Any concentric muscle activity implemented with an articulated member will invoke an eccentric movement from the counterpart muscle...including"motive" forces.

In our skiing, this is of high import, due to the fact that what we choose, as pilots of both our innate physiques and of our hardware, which movements will be proactive and which will be reactive.
In the case of the "pulling back" of a one ski/foot, this should really only ever be a reactive, passive movement, while the pushing forward of a ski/foot should always be a proactive and intentional, powered movement.

What we (believe we) see elite athletes doing is often a 50/50 gamble, when we take into consideration the difficulty in divining whether the movement is active or passive.
What appears to be active pulling back of the foot is, typically, a passive stasis of the foot as the skier's CM recenters over it.

While pursuing my Swiss level III at Arosa, this philosphical/mechanical aspect, and we students' understanding and application of it, was a deciding factor in qualifying for this coveted pin.
post #66 of 167
Quote:
Originally Posted by william blake View Post
With all respect- assuming that by
"contration" you mean contraction,
you've got it backward
.
Eccentric movement is extension, not contraction.
Eccentric movement does push things....almost exclusively. think of a bench press, or a ski as we extend our leg.
Bear in mind that eccentric movement is as much a part of skiing as concentric movement, as:

A. The return to neutral stance, from either, entails the employment of the oppsosite force

B. Any concentric muscle activity implemented with an articulated member will invoke an eccentric movement from the counterpart muscle...including"motive" forces.

In our skiing, this is of high import, due to the fact that what we choose, as pilots of both our innate physiques and of our hardware, which movements will be proactive and which will be reactive.
In the case of the "pulling back" of a one ski/foot, this should really only ever be a reactive, passive movement, while the pushing forward of a ski/foot should always be a proactive and intentional, powered movement.

What we (believe we) see elite athletes doing is often a 50/50 gamble, when we take into consideration the difficulty in divining whether the movement is active or passive.
What appears to be active pulling back of the foot is, typically, a passive stasis of the foot as the skier's CM recenters over it.

While pursuing my Swiss level III at Arosa, this philosphical/mechanical aspect, and we students' understanding and application of it, was a deciding factor in qualifying for this coveted pin.
Well I don't have eccentric contraction wrong but maybe we have a language barrier happening. Eccentric contraction is simply muscles contracting as they get longer. As in doing a squat or letting the dumb bell in your hand slowly return down after lifting it. Eccentric contraction, and I assume you mean this when you say eccentric movement, requires an outside force that is greater than the contracting force in the muscle. It can also mean the muscle is doing antagonist duty as well as you point out, except that in this duty the muscle is still lengthening as the agonist muscle or motive force prevails as the contraction moves the joint.

Not really sure what you are trying to say here.
post #67 of 167
Quote:
Originally Posted by RicB View Post
Well I don't have eccentric contraction wrong but maybe we have a language barrier happening. Eccentric contraction is simply muscles contracting as they get longer. As in doing a squat or letting the dumb bell in your hand slowly return down after lifting it. Eccentric contraction, and I assume you mean this when you say eccentric movement, requires an outside force that is greater than the contracting force in the muscle. It can also mean the muscle is doing antagonist duty as well as you point out, except that in this duty the muscle is still lengthening as the agonist muscle or motive force prevails as the contraction moves the joint.

Not really sure what you are trying to say here.

"eccentric contraction" is a contradiction, an oxymoron.

Muscles do not contract when the elongate; nothing does.

When one 'returns' a dumbbell 'after lifting it', that's a passive eccentric movement, and an extension, at that...Not a contraction. It may follow a recent contraction, but that 'return' is an extension, as the angle of the arm becomes more obtuse.

No 'language barrier', just terms being misused, inversely.

The foot should never be actively pulled back (the corollary unweighting would create a displacement disparity between the two feet, which is what we should be working to overcome in the upper levels), it should only ever be pushed forward, with an ensuing forward movement of the CM to regain neutral stance above it, be it from the hips or the entire torso.
post #68 of 167
I have been accused of being eccentric but the only time I get elongated is after a few beers.
post #69 of 167
There are three types of mucle contractions:

1) Concentric contraction: the muscle shortens
2) Isometric contraction: he muscle stays the same length
3) Eccentric contraction: the muscle lengthens
post #70 of 167
Quote:
Originally Posted by Pierre View Post
I have been accused of being eccentric...
You are.
post #71 of 167
JASP and RickB are really saying the same thing and I agree. The foot pull back thing is totally unnessesary if people would learn to balance on a steepening and then less steepening incline and learn to effectivly balance between their feet (skis). This refers back to another thread labeled "how to teach balance". The first step is awareness of balanced skiing and unbalanced skiing. If people want to improve their skiing dramatically, they need to first get balanced and then stay balanced. Pulling feet is a bandaid approach that only treats symptoms.

RW
post #72 of 167
Quote:
Originally Posted by Ron White View Post
Pulling feet is a bandaid approach that only treats symptoms.
It would be interesting to see vid of all of the posters that suggest that pulling the foot (feet) back isn't necessary. After watching some very good skiers that last few days I'm thinking that the majority of advanced skiers (and instructors) are a bit aft and they don't even realize it.
post #73 of 167
Quote:
Originally Posted by RicB View Post
But then I'm not the one who said that we could increase pressure without increasing weight.
What happens if 100% of the weight is on the outside foot and then the skier either moves his foot back so its under the hips or moves his hips forward so they are over the feet? Funny how that increases the pressure felt under the foot and yet the weight on that foot hasn't changed.
post #74 of 167
Quote:
Originally Posted by Ron White View Post
JASP and RickB are really saying the same thing and I agree. The foot pull back thing is totally unnessesary if people would learn to balance on a steepening and then less steepening incline and learn to effectivly balance between their feet (skis). This refers back to another thread labeled "how to teach balance". The first step is awareness of balanced skiing and unbalanced skiing. If people want to improve their skiing dramatically, they need to first get balanced and then stay balanced. Pulling feet is a bandaid approach that only treats symptoms.

RW
Mebbe so, but I sure ain't perfect. It's a sport of movement, and I'd be really surprised if I ever reached the point where I was always in perfect balance and never had to react to getting out of balance, either because I did something stupid, or the terrain did something that I failed to correctly anticipate, or ...

I know what I regard as ideal, and I know that I rarely ski that way. Now, it's possible, even probable, that I'm relatively incompetent, and that most people here never have to move to balance because they're already there.

Of course, many of these same people will complain about how their quads burn after skiing powder or crud or bumps all morning. Where do you suppose they've been keeping their CoM relative to their feet?

Given that we get out of balance and want to move back toward balance, what's the best way? Or, what focus will best help athletically disadvantaged dweebs like myself best stay in balance? I think that's more or less the original question that started this thread.

The answer is, it depends. It depends on who you are, what thoughts trigger what movements, what terrain you're skiing, what the snow conditions are, what sort of imbalance you're trying to recover from, and, of course, your sign and the phase of the moon. What works for me (but sometimes doesn't) might never work for you.

We might note also that attempting to ski in perfect balance at all times can lead to some very boring, static skiing. We move to balance, but we rarely stay there. Unbalanced forces are required for acceleration, and in skiing, we hardly ever move in a straight line at a constant speed. We speed up, we slow down, we arc left, we arc right, we balance briefly (but not exactly) against some of the constantly varying forces acting on us, while giving in to others.

A graceful, elegant, powerful skier is actually managing imbalance beautifully rather than rigidly maintaining balance.
post #75 of 167
Quote:
Originally Posted by william blake View Post
"eccentric contraction" is a contradiction, an oxymoron.

Muscles do not contract when the elongate; nothing does.

When one 'returns' a dumbbell 'after lifting it', that's a passive eccentric movement, and an extension, at that...Not a contraction. It may follow a recent contraction, but that 'return' is an extension, as the angle of the arm becomes more obtuse.

No 'language barrier', just terms being misused, inversely.

The foot should never be actively pulled back (the corollary unweighting would create a displacement disparity between the two feet, which is what we should be working to overcome in the upper levels), it should only ever be pushed forward, with an ensuing forward movement of the CM to regain neutral stance above it, be it from the hips or the entire torso.
Me thinks you need to do a little more reading.

Eccentric contraction, A contraction in which a muscle exerts force, lengthens, and is overcome by a resistance.

Extension is a term used to describe an increase in the angle of two bones, nothing more and nothing less.

Flexion describes the decrease of the angles between two bones.

I'll leave you to figure it out.
post #76 of 167
Quote:
Originally Posted by Max_501 View Post
What happens if 100% of the weight is on the outside foot and then the skier either moves his foot back so its under the hips or moves his hips forward so they are over the feet? Funny how that increases the pressure felt under the foot and yet the weight on that foot hasn't changed.
Why don't you tell me what causes the increase of pressure you feel under the foot Max?
post #77 of 167
Quote:
Originally Posted by BigE View Post
There are three types of mucle contractions:

1) Concentric contraction: the muscle shortens
2) Isometric contraction: he muscle stays the same length
3) Eccentric contraction: the muscle lengthens
For more detailed info:

http://www.twu.edu/biom/3591Labs/Ele...ontraction.htm
post #78 of 167
Quote:
Originally Posted by RicB View Post
Why don't you tell me what causes the increase of pressure you feel under the foot Max?
Heck, how would I know? I'm just a dumb PMTS dude.
post #79 of 167
Wow! I've never been accused of trying to be perfect. Nothing could be further from the truth though. What I have written here is pretty common stuff that has been around for a very long time. Refining your balancing skills allows you to be more centered more often. Those who can do so all of the time put forth the effort to become that good. Give them their due instead of assuming that something cannot be done because you cannot do it.
post #80 of 167
Quote:
Originally Posted by justanotherskipro View Post
Wow! I've never been accused of trying to be perfect. Nothing could be further from the truth though. What I have written here is pretty common stuff that has been around for a very long time. Refining your balancing skills allows you to be more centered more often. Those who can do so all of the time put forth the effort to become that good. Give them their due instead of assuming that something cannot be done because you cannot do it.
If its any consolation JASP I do teach on the snow what you have been saying. But we ain't on snow we are in cyberspace. :
post #81 of 167
A semantic issue presents here- the use of pop-fitness culture terminology to argue against literal, physical terminology is muddling some terms.
Putting that aside, there is no effective reason for "pulling" a foot back, this runs contrary to solid form and balance.
sometimes, the little tricks define a skier's departure from working on truly efficient, smooth delivery.
This represents such a scenario.
remember that pressure is always measured by weight, but in execution, the two needn't be synonymous.

"Weight", for the purposes of Skiing mechanics, refers to static (passive) load.

"Pressure" entails an active, movement-generated (however subtle) load.

Both are forms of weight, one active, one passive.
post #82 of 167
Quote:
Originally Posted by RicB View Post
Why don't you tell me what causes the increase of pressure you feel under the foot Max?
Gravity pulling pulling you down the fall line while your ski carves up?
Think G-forces etcetera.
Granted, once pressurised the unweighted foot won't remain unweighted unless you pull it up even more and then the presuure falls again.

It is however perfectly possible to get pressure on a previously unweighted foot without transfering any body weight or pressure to that foot. Terrain does that.
post #83 of 167
Pressure is measured in mass/area, like pounds/sq ft.

An unweighted foot cannot be pressured.
post #84 of 167
Quote:
Originally Posted by william blake View Post
Putting that aside, there is no effective reason for "pulling" a foot back, this runs contrary to solid form and balance.
sometimes, the little tricks define a skier's departure from working on truly efficient, smooth delivery.
This represents such a scenario.
Are we talking in terms of everyday recreational skiing (The way to ski), learning situations/ teaching a student or specialized circumstances such as racing?
post #85 of 167
Quote:
Originally Posted by BigE View Post
3) Eccentric contraction: the muscle lengthens
Being a non-native English speaker I have to admit that a lengthening contracting sounds a bit contradictive.
The Dutch equivalent of to contract means to pull together, to shorten.
It is possible that contraction the way you guys use it is a standardised expression for a muscle delivering force.

We would use eccentric force or eccentric power.

However I'll gladly take eccentric contraction for what it is in your definition though!
My understanding of the English language has once again been improved!!
post #86 of 167
post #87 of 167
Quote:
A semantic issue presents here- the use of pop-fitness culture terminology to argue against literal, physical terminology is muddling some terms.
The only pop-fitness culture terminology is coming from those who refuse to accent the science of physiology.

Look muscles are like big cylinders. the cylinders contain myofibrils, which are filled with two proteins, Myosin, and Actin. the muscle also have repeating units called sarcomeres. So think of a sarcomere as a pair of stiff bristled hair brushes. the bristles have one of two types of bristles exsclusively, with one type being coated with myosin and the other type is coated with actin. When charged the two protien coatings on the bristles attract each other and pull the brushes together. How many muscle fibres are recruited determines how strong the pull of the muscle is. Here where eccentric contraction comes into play. The attraction of the bristles towards each other does not go away when the force acting on the body is greater than the contracting force of the muscle fibres. The brushes are simply pulled apart. How fast or slow is directly dependant on the resistant forces acting on the body versus the force of the recruited muscle fibres. The muscle contracts as it gets longer.

We use this mechanism to control the influence of outside forces as well as to control our own movment by balancing and controlling our intended movement. Muscle fibres are either on or off. They can't half contract. We only have control of movement through this balancing of one muscle shortening as it contracts and an opposing muscle contracting as it gets longer. This remains true whether you are here in America, Europe, Africa, Asia, or in outer space.
post #88 of 167
RicB,
Well said! Resisting but not stopping the lengthening of the muscle!!!
post #89 of 167
This is exactly the action we called replemont, or passive flexing.
post #90 of 167
jhcooley,

Quote:
We might note also that attempting to ski in perfect balance at all times can lead to some very boring, static skiing. We move to balance, but we rarely stay there.
I couldn't disagree more, balanced skiing is fluid, exciting skiing. Are you able to swich from carving around a turn, to stepping at any point in the turn you want? Are you able to go from terminal velosity long carved turns to short turns at any time? Able to ski any pitch and snow condition effectivally? If not, there is a big balance issue. Once you can get balanced and keep balanced, skiing gets totally fluid, exciting and dynamic.

Lessons that don't force the student to find balance on skis lead to boring, static skiing. Most recreational skiers are so out of balance they can hardly do any effective movements, only try to make corrective movements. Most ski instructors are in better balance, but few understand how to balance on a ever varing pitch or incline as their skis pass the fall line, leaving them out of balance to make the next turn. The sooner they regnigize it, the sooner they can be on the path to balanced skiing (with some coaching). Hopefully some day you will understand what I'm talking about.

RW
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