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Avalement (Absorption) Animated! - Page 2

post #31 of 49
There is a definite opening of the ankles between frames 3 and 4 - the shin to boot angles are quite different.
post #32 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
But it is important to understand that "pushing the feet ahead" absolutely does not need to entail "opening his ankles" (plantar flexion), nor does pulling the feet back require dorsiflexing the ankles--as Stickman and the bump skier demonstrate. We can demonstrate it ourselves--stand up and lift one foot off the floor. Now move that foot forward and back. The movement comes not in the ankle, of course, but in the knee and/or the hip. And without ankle motion, your foot tips toes down when you pull it back, and toes up when you push it ahead--just as it needs to when absorbing a bump.
Bob,

In general, I like everything you're saying here and the animations are great .

However, your example above is using a top-down open kinetic chain movement with the foot in almost terminal plantarflexion.... That doesn't apply to the bottom-up closed kinetic chain (assuming your skis are on the ground) mechanics of skiing where the foot is in a position of relative dorsiflexion.

I like your 'cuff neutral' approach to bumps, but I would argue that outside of modelling - in the real world on hill - that there are multiple, fast, small range of motion movements of the ankle (some active, some reactive) that occur in order to keep you cuff neutral. An EMG study would probably help to clarify this .
post #33 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
Once I reach the end of the range--in other words, once I'm pressed up against my boot cuffs--it's gone, and I've effectlvely locked up my ankles. When that happens, any further flexion or extension must occur higher in the kinetic chain. When a skier gets bucked forward at the waist by a bump or a big pile of heavy crud, that's what happens--he hits the "wall" of his boot cuffs, which pushes his legs back while his upper body continues forward. Tumbling "over the handlebars" may amuse onlookers, but I prefer to do it rarely!

So I seek to develop movements of my knees, hips, spine, and arms that allow me to remain "cuff neutral"--or to move my ankles independently as needed--at all times, on every part of a bump, and every phase of a turn. That's what the "backpedaling" animation shows. Like the bump skier in the photosequence you referred to, "Stickman" moves his feet forward and back beneath his hips--a lot.
I think I am the pink guy

I try to stay centered and wind up driving my knees forward into the cuff. So my reaction is to soften the boot more.

Tuesday at Mad River the bumps were incredible. I was moving my feet into the troughs and forward naturally. In the past, when I was aware of this forward movement I tried to correct it and stay centered. At MRG I did try to correct. I have always believed it to be wrong. Allowing the feet to move forward is a natural movement.

Great discussion.

The cuff neutral discussion in 4ster's MA worked great. See if I can get it to work in the bumps too.
post #34 of 49
Thread Starter 
Hi Paul--now would be a good time to check out the spring sales for a new non-pink outfit! Yes-give yourself permission to let your feet get out from underneath you at times. The dogmatic "conventional wisdom" that we should try to keep our hips over our feet is--and always has been--a mistake!

Best regards,
Bob
post #35 of 49
Thread Starter 
Quote:
I like your 'cuff neutral' approach to bumps, but I would argue that outside of modelling - in the real world on hill - that there are multiple, fast, small range of motion movements of the ankle (some active, some reactive) that occur in order to keep you cuff neutral.
Yes--that's exactly what I'm saying, Jdistefa. The movements that allow us to stay "cuff neutral" are the "default" patterns that good skiers must develop, as a base for the infinitely variable situational requirements of real skiing. Only when you can remain cuff neutral do you have the freedom to shift pressure forward or back at willl, any time, as needed!

The same is true of the static exercise I described above. As you move your lifted foot forward and back beneath your hips, or even move it in the "reverse pedaling" circular motion of the Stickman animation, it is the same motion, involving the same joints, as the actual movement pattern in bumps. The foot tips up as it moves forward--just as it must when rising up a bump--and down when it moves back, with no ankle motion required whatsoever. So the ankle is free to move independently to adjust fore-aft balance and to react to the little "non-sine-wave-like" irregularities of real snow.

Best regards,
Bob
post #36 of 49
Thread Starter 
Quote:
There is a definite opening of the ankles between frames 3 and 4 - the shin to boot angles are quite different.


Hi BigE--

I'm not convinced that what you see is evident in that sequence, and I have a larger, higher resolution version of it. His skis do tip up considerably between those two frames, as his shins become more upright. But I'd like to think you're right, because it supports my points a) that it is not necessary to flex the ankles (dorsiflex) as you absorb a bump, and b) that with proper movement patterns of the knees, hips, spine, and arms you are free to do with your ankles anything you need--including the plantar flexion ("opening the ankles") you refer to.

And with that, I'm on my way to Arapahoe Basin to take advantage of this cloudless blue sky spring skiing day!

Best regards,
Bob
post #37 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
Yes--that's exactly what I'm saying, Jdistefa. The movements that allow us to stay "cuff neutral" are the "default" patterns that good skiers must develop, as a base for the infinitely variable situational requirements of real skiing. Only when you can remain cuff neutral do you have the freedom to shift pressure forward or back at willl, any time, as needed!

The same is true of the static exercise I described above. As you move your lifted foot forward and back beneath your hips, or even move it in the "reverse pedaling" circular motion of the Stickman animation, it is the same motion, involving the same joints, as the actual movement pattern in bumps. The foot tips up as it moves forward--just as it must when rising up a bump--and down when it moves back, with no ankle motion required whatsoever. So the ankle is free to move independently to adjust fore-aft balance and to react to the little "non-sine-wave-like" irregularities of real snow.

Best regards,
Bob
Bob,

Thx for the reply, and I enjoy reading your stuff.

I would just repeat that you're going to get nailed by someone if you use an open kinetic chain example to explain a closed kinetic chain system .

Regards,
Matt
post #38 of 49
Thread Starter 
Quote:
you're going to get nailed by someone if you use an open kinetic chain example to explain a closed kinetic chain system
Ah--perhaps so, jdistefa. But such nailage will need to dig into how and why the one example might not be relevant to the other. The leg movements of my static example are identical to the movements of actual bump absorption, so I maintain that the example is fully relevant to the point, open and closed kinetic chains notwithstanding.

Furthermore, while I'm not a physical therapist and claim no expertise in the nuances of open and closed kinetic chain exercises, my limited understanding of the concept suggests that my static example and the "real skiing" situation it models are actually both open kinetic chain systems. As I understand it, in a closed kinetic chain exercise, the distal segment of the chain (in this case, the foot) must be fixed, to the extent that it doesn't move in response to the muscular effort applied to it. Since the feet are nearly as free to move forward and back beneath the body when sliding on the snow as they are when lifted in the air, I believe that skiing would qualify as an open kinetic chain situation, at least with respect to the fore-aft movements we're discussing in this particular situation.

Either way, I am not convinced that there is much point in distinguishing between open and closed kinetic chain in this case. Whether it is or isn't, has no bearing on the similarity of the movements used in my example to the skiing movements they are meant to simulate. It is merely to demonstrate this similarity that I described the exercise--don't read too much into it!

I'd be very interested in hearing from someone who has more familiarity with the significance and uses of open and closed chain exercises. Anyone out there care to shed some light on this?

Best regards,
Bob
post #39 of 49
Quote:
Originally Posted by BigE View Post
There is a definite opening of the ankles between frames 3 and 4 - the shin to boot angles are quite different.
FWIW, I see the difference in the angles as well. In terms of skiing more direct in the bumps, the coaching I got was focused on flexing and opening at the ankles.

And another FWIW, alot of wc bumpers alter their boot setup to get a softer a flex and to get more range. It seems the Lange boot is a popular design to alter to achieve the above. Then you have another group of bumpers who like the "open throat" of the flex comp and now full tilt/dalbello krypton; both men and women 06 Olympic mogul champs ski with that three piece cabrio design.

A third FWIW, using a wc bumping montage to advocate a cuff neutral or a stiff boot approach is analogous to using britney spears as a spoke person to advocate morality in music videos.
post #40 of 49

ankle is where its at

I tend to agree with Jack97 here - the greater the ankle can flex, the easier to "stall" on the front face and maintain ski to snow contact on the
back side. if i skied bumps in doberman 150's i might have different ideas.
(an impressive feat in and of itself)


furthermore, more ankle flex allows the skier to remain taller (ie more vertical in the femur), which means the fore - aft dance of feet and hips does not take as much time - which means the the hips can get (back) over the feet sooner to be ready for the next mogul.

i think somewhat that WC skiers today let the shovel of the ski take a beating, then the ankles, then the larger ranges of motion find in the knee and hips.

i also think stickman would extremely fatigued after dropping his rear end so drastically for each mogul

but mostly i wish i was skiing hero bumps instead of getting a tan here in ohio were hit 84 yesterday

brad
post #41 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
Oh--and welcome to EpicSki, Bazza!
Thanks Bob - I love your animations; I sit and watch them for far too long than is good for me!!

I really struggled with bumps on my annual ski week at Easter. I feel superb at carving but don't seem to be able to carry it over to the bumps and off-piste. Yet I keep hearing the technique is the same.

These animations have really helped me see what I need to do to keep contact with the snow. But then I can't work out should I skid or carve? Or is it skid then edge? Then I see some stuff making it look like you should go over the bump then turn and some stuff looking like you turn before you get to the top of the bump.

I think I'm putting too much weight on the inside ski. Would I be right in thinking the weight should be on the outside ski (or the ski that is about to become outside) even in bumps and powder?

Also both these clips seem to advise get over the bump then turn?

http://uk.youtube.com/watch?v=xrkp0i...eature=related

I don't speak Danish but I think he's saying tackle them the way they were made.


http://uk.youtube.com/watch?v=J9P6IQxDLYg

I tried this one and got on okay but couldn't stay on my feet off-piste and really struggled with narrow paths with bumps - no room to turn and control speed.
post #42 of 49
Quote:
Originally Posted by docbrad66 View Post
furthermore, more ankle flex allows the skier to remain taller (ie more vertical in the femur), which means the fore - aft dance of feet and hips does not take as much time - which means the the hips can get (back) over the feet sooner to be ready for the next mogul.
So are you saying that you can't be cuff neutral and remain taller. Do these aspects apply to bump skiing: backpedaling, moving the feet forward approaching the bump, and staying off the cuff? Is it true that once you are up against the cuff, the ankle looses mobility? If we look at WC bumpers will we see some of this cuff neutral stuff in action? Or do they prefer to drive the knee into the cuff?

I think Bob's points are valid. I've been over the handle bars. I've lost ankle mobility from pressuring the cuff.

I guess the questiong that I still have is, what amount of cuff pressure is ok and at what point, is pressuring the cuff ok. I use the cuff to leverage the front of the ski too much, but some shin to boot does seem to work.
post #43 of 49
Quote:
Originally Posted by Paul Jones View Post
So are you saying that you can't be cuff neutral and remain taller. Do these aspects apply to bump skiing: backpedaling, moving the feet forward approaching the bump, and staying off the cuff? Is it true that once you are up against the cuff, the ankle looses mobility? If we look at WC bumpers will we see some of this cuff neutral stuff in action? Or do they prefer to drive the knee into the cuff?

I think Bob's points are valid. I've been over the handle bars. I've lost ankle mobility from pressuring the cuff.

I guess the questiong that I still have is, what amount of cuff pressure is ok and at what point, is pressuring the cuff ok. I use the cuff to leverage the front of the ski too much, but some shin to boot does seem to work.
Here's an article of Bob Barnes from the alternate universe (WP); he talks about using functional ankle tension (FAT) to pressure the front of the boots.

http://www.skinet.com/article.jsp?ID=1000041292


And the handle bar thing, IMO wc bumpers mitigate this by pressure management and a boot that will respond progressively to the frontal pressure. That's why they alter their boots or go with the cabrio design.

BTW, I have no bone to pick on a cuff neutral approach but using the WC montage to justify it is another matter.
post #44 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
Ah--perhaps so, jdistefa. But such nailage will need to dig into how and why the one example might not be relevant to the other. The leg movements of my static example are identical to the movements of actual bump absorption, so I maintain that the example is fully relevant to the point, open and closed kinetic chains notwithstanding.

Furthermore, while I'm not a physical therapist and claim no expertise in the nuances of open and closed kinetic chain exercises, my limited understanding of the concept suggests that my static example and the "real skiing" situation it models are actually both open kinetic chain systems. As I understand it, in a closed kinetic chain exercise, the distal segment of the chain (in this case, the foot) must be fixed, to the extent that it doesn't move in response to the muscular effort applied to it. Since the feet are nearly as free to move forward and back beneath the body when sliding on the snow as they are when lifted in the air, I believe that skiing would qualify as an open kinetic chain situation, at least with respect to the fore-aft movements we're discussing in this particular situation.

Either way, I am not convinced that there is much point in distinguishing between open and closed kinetic chain in this case. Whether it is or isn't, has no bearing on the similarity of the movements used in my example to the skiing movements they are meant to simulate. It is merely to demonstrate this similarity that I described the exercise--don't read too much into it!

I'd be very interested in hearing from someone who has more familiarity with the significance and uses of open and closed chain exercises. Anyone out there care to shed some light on this?

Best regards,
Bob
Bob,

You're right, skiing is complex in that the platform can be relatively fixed (loading phase of a purely carved turn) vs. very fluid in multiple planes (powder, crud, steered turns, bumps). In other words, things can vary from a closed kinetic chain system to a gray area in the spectrum between closed and open chain systems.

Obviously jumping converts things to open chain .

To avoid further minutaie-itis, I'll PM you for further discussion.

Regards,
Matt
post #45 of 49
Quote:
Originally Posted by jack97 View Post
functional ankle tension (FAT) to pressure the front of the boots.
BTW, I have no bone to pick on a cuff neutral approach but using the WC montage to justify it is another matter.
So WC bumpers do not like the cuff neutral approach. I thought that the montage demonstrated cuff neutral nicely. I'll have to watch for it in the vids.

Don't know what FAT is.

I feel that Bob is on the money in this discussion in so far as the issues and problems that I have experienced in my more traditional bump skiing. My boots are the Nordica 130 - softened. I can relate to his explanation of the ankle being imobilized by cuff pressure.

I also can't quite see how my turns would fair without some pressure on the front of the ski. But this is probably more limited thinking on my part than fact. Over the years I have hit the cuff to leverage the ski, to turn. Over the years I have also gone over the handle bars:

All of the cuff neutral concepts that I have picked up on Epic have been functional and clearly make a difference in my skiing. I need to take this out with me and try it in the bumps.
post #46 of 49
Quote:
Originally Posted by Paul Jones View Post
So WC bumpers do not like the cuff neutral approach. I thought that the montage demonstrated cuff neutral nicely. I'll have to watch for it in the vids.
IMO, it seems that he putting alot of pressure on the front before and after cresting the bumps. But I still see a difference in ankle flex in that montage.


Quote:
Originally Posted by Paul Jones View Post
Don't know what FAT is.
Per the article of Bob Barnes of Winter Park, lift the toes, it makes the shins pressure the boot. Evan Dybvig made me do it more bluntly, tense the tibialis muscle, this forces the ankle to flex.


Quote:
Originally Posted by Paul Jones View Post

I feel that Bob is on the money in this discussion in so far as the issues and problems that I have experienced in my more traditional bump skiing. My boots are the Nordica 130 - softened. I can relate to his explanation of the ankle being imobilized by cuff pressure.
I think Bob Barnes of Keystone is spot on with cuff neutral when it comes to stiff boots or boots that hit the wall in terms of flex. In this case it will limit ankle range and in another case, the bumps knocking you to the backseat if your flexed too much.
post #47 of 49
Thread Starter 
Mornin' everyone! I only have time for a few quick notes, but there are some points that I fear may be getting lost.

First, the Backpedal animation is definitely not about advocating "cuff neutral," or any other particular fore-aft stance. It is about the movements of the knees, hips, spine, and arms that are required to maintain any fore-aft relationship on your skis. Whether your preference is cuff neutral, light contact with your boot tongues, heavy pressure on your boot tongues, or pressure on the backs of your boots, the same cyclic fore-aft movements are needed to maintain any of them. Only with these movements as a foundation will you have the ability to regulate your fore-aft pressure as you choose, when you choose.

Second, cuff neutral, or any other relationship, does not preclude "functional ankle tension," which I agree is a critical component of good skiing.

Third, yes, skiing a stiff, snug-fitting boot like the Dobermann 150 will certainly highlight the need for these precise, accurate movements. Make a mistake in bumps, and you will pay for it. And you will make mistakes! Softer boots are, without a doubt, more tolerant of errors, and that forgiveness is a benefit in high-speed, competitive style bump skiing. But I maintain that it is not to enable the ankles to flex and extend as fundamental "default" movements that competitive bumpers like softer boots--it is simply to decrease the demand for absolute (and unattainable) precision--to tolerate inevitable "errors." Your mileage may vary.

Ironically, extremely soft boots will also heighten the requirement for the moves in queston. If your boots give you no support, no ability to recover from imbalance, you'd better be accurate! Skiing with boots unbuckled, soft boots or boots set in "walk" mode to unlock the cuffs, or skiing bumps on telemark gear, all highlight the importance of these movements.

Fourth, the photo sequence of the bump skier--who is, in fact, a World Cup competitor in competition--may well show a slight extension ("opening") in the ankles between the third and fourth frames. I think appearances may be deceiving here, since his skis tip up as they hit the bump, keeping his ankles more consistently flexed than it may look at first glance. But either way, it certainly doesn't appear that he is flexing (dorsiflexing) his ankles at that moment, which supports my point that dorsiflexing the ankles is not required to absorb a bump and that proper movements of the entire body give the skier the freedom to do whatever he needs or wants with his ankles, at any time.

Carry on!

Best regards,
Bob
post #48 of 49
Quote:
Originally Posted by Paul Jones View Post
So are you saying that you can't be cuff neutral and remain taller. Do these aspects apply to bump skiing: backpedaling, moving the feet forward approaching the bump, and staying off the cuff? Is it true that once you are up against the cuff, the ankle looses mobility? If we look at WC bumpers will we see some of this cuff neutral stuff in action? Or do they prefer to drive the knee into the cuff?
my comments were in relation to stickman, whose "femurs" go nearly horizontal while (by design) is cuff neutral.

furthermore, i think "against the cuff" is perhaps not as well defined as it sounds, as well as being boot dependent. when i teach never-evers i often lean way forward and then way back to show them that they really can get there hips up over their feet. (i do this at the base of the bunny hill, not while moving). my boots are snug enough that my i am contact with both the tongue and the rear cuff, but soft enough to allow a range of motion in my ankle, which translates to a very large range of motion of my head, it being almost 6 feet away from the pivot point.

as for wc, i think they need to "manage speed" by keeping the skis on the snow (particularly on the downhill side of the mogul) by:
getting the tips on the snow as soon as possible (open the ankle)
driving the knees to the inside of the turn, which includes pressure
on the cuff


brad
post #49 of 49
Quote:
Originally Posted by Bob Barnes/Colorado View Post
First, the Backpedal animation is definitely not about advocating "cuff neutral," or any other particular fore-aft stance.
I agree, the backpedal animation has nothing to do with cuff neutral.


Quote:
Originally Posted by Bob Barnes/Colorado View Post
Third, yes, skiing a stiff, snug-fitting boot like the Dobermann 150 will certainly highlight the need for these precise, accurate movements. Make a mistake in bumps, and you will pay for it. And you will make mistakes! Softer boots are, without a doubt, more tolerant of errors, and that forgiveness is a benefit in high-speed, competitive style bump skiing.
But when making statement as the above, it leaves room for question.

I know from first hand wc bumpers don't like stiff boots not b/c it gives them less room for error, they hate them b/c they don't have enough range for flexing. When these guys are doing the drills below, its about applying pressure to the shins to control the descent.

http://www.youtube.com/watch?v=rdpqkmXUGX0

Also, some have been know to go several sizes down in the boots when competing, they want the precision when making the turns but still allow a softer flex to apply the front pressure. A softer flexing boot does not imply more room for error.
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