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Center of Mass work in bumps today

post #1 of 14
Thread Starter 
Today I happen to hit the jackpot on conditions for working on Center of Mass movements in my own skiing. The prediction was for an ice storm followed by rain so the ski hill was empty. That storm really didn't materialize but the bumps were none the less a solid ball of ice this morning. Now I cannot resist bumps of solid ice so I ventured in.

These bumps are irregular tight diamond shaped with ruts on a green/blue run (by western standards) and very typical of midwestern bumps. The bumps were fairly smooth with clickety clack type ice in the morning gradually giving way to slush in the afternoon.

I started out with a couple of runs through to get the feel of the conditions and then proceeded to working on Center of Mass movement by means of one footed skiing and skiing with no poles.

When the conditions were icy, I found it easy to ski on one ski in the bumps as there was little resistance to making a round buttered turn. I found it easy with no poles and ran into difficult skiing when I ditched the poles and skied on one ski. I am not sure what my problem on one foot is with Center of mass movements once the poles are gone but I did discover new meaning about turn shape and center of mass movement.

As the bumps became slushy and others started to ski them I found it very difficult to ski on one ski even with poles because the resistance underfoot made it difficult to run a round line through the bumps. Without that ability to set a round line I found it difficult to release the Center of Mass into the new turn and my speed would increase until I was in the back seat and had to put both feet down. Once both feet were on the snow, a round line was once again possible and center of mass release and speed control was easy but them slushy bumps were substantially more work than when the bumps were an ice cube.

Now I realize the reason that skiing became harder on one ski in slush is because you do not have the ability to fulcum between your feet but that was not the issue.

My issue was one of when skiing a round line, the center of mass was easy to release by pulling the foot back and letting the center of mass go but when the round line was restricted, I found it nearly impossible to draw the foot back underneath me.

My question now becomes Does release of the center of mass facilitate a round turn or does a round turn facilitate the release of the center of mass?
I am aware of the fact that skiers who do not release their center of mass into the new turn never seem to ski a round turn so I was assuming that release of the center of mass facilitated a round turn but now I am not sure.

Could it be that my observation is confusing me just because and idiot who isn't strong enough tried to ski slushy bumps on one ski or am I missing something?
post #2 of 14
Quote:
Originally Posted by Pierre View Post
When the conditions were icy, I found it easy to ski on one ski in the bumps as there was little resistance to making a round buttered turn. I found it easy with [no] poles and ran into difficult skiing when I ditched the poles and skied on one ski. I am not sure what my problem on one foot is with Center of mass movements once the poles are gone but I did discover new meaning about turn shape and center of mass movement.

I'm assuming you meant to say: I found it easy with poles and ran into difficult skiing when I ditched the poles and skied on one ski.

So, how exactly are you buttering that turn on one ski then, if you removed the other leg to turn against?????

A bit of counter-rotation perhaps, that works quite nicely (maybe not too easy to see) on that low friction icy surface? That wouldn't explain the poles though, eh! Would explain why it collapses in the slush though, when the surface resists your ski twisting.

Were you dragging your poles? That pole contact will replace your lifted leg as a fulcrum mechanism! Then when ya put them away you lose your fulcrum.

Of course, a plain ole blocking pole plant would do it as well.
post #3 of 14

COM switch?

Quote:
Originally Posted by Pierre View Post
... icy bumps... and then proceeded to ... one footed skiing and skiing with no poles...
Pierre, you forgot to try doing them bacwards... (I still have to see that).

I believe I have seen you in the bumps without the poles . At the time you complained they were not icy enough to your liking. (It was hard fo me to relat to that. ) I can imagine you on one ski, but backwards?
Or were you pulling my leg?

May be I should join you at ST this week to see all this in person and analyze the cause and effect? I do not think there will be many takers for lessons after those rains...

Your friend,
AE
post #4 of 14
Thread Starter 
Quote:
Originally Posted by cgeib View Post
I'm assuming you meant to say: I found it easy with poles and ran into difficult skiing when I ditched the poles and skied on one ski.

So, how exactly are you buttering that turn on one ski then, if you removed the other leg to turn against?????

A bit of counter-rotation perhaps, that works quite nicely (maybe not too easy to see) on that low friction icy surface? That wouldn't explain the poles though, eh! Would explain why it collapses in the slush though, when the surface resists your ski twisting.

Were you dragging your poles? That pole contact will replace your lifted leg as a fulcrum mechanism! Then when ya put them away you lose your fulcrum.

Of course, a plain ole blocking pole plant would do it as well.
cgieb I am aware of the fact that the minute you have one foot off the ground you loose the ability to steer by means of independent leg rotation and must replace this with something else (body rotation) in anything but runing the arc of the single ski.

There are also those who say that rotary is passive and totally unecessary for skiing. If that is the case, then one footed skiing should also apply.

I remain totally convinced that independent leg rotation is a very useful powerfull tool especially is short turns involving crud and slush. No way would I eliminate this tool from my tool box.

cgeib I know your level of understanding and what you are fishing for, I do the same thing in Epicksi when I think someone is missing the boat. Many high level instructors here are convinced that upper body rotation must be present on one ski as independent leg rotation is gone. I respect those views and have no problem with them prevailing.

For myself, I am not convinced there is not a way to tip the ankle and release the CM into the new turn in such a way that the technology in the ski is the turning force and not some upper body rotation. One ski skiing is the only sure way to prove this. When conditions are right for my level of balance, I can definitely feel an engagement of the inside tip and my upper body quiet while skiing into counter. I use a light pole touch no different from my normal skiing. I think the pole touch is simply a third balance point in this case. I was not dragging or using a pole plant as a fulcurm mechanism. Outside of the bumps I can feel this tip/pressure/tip engagment in slightly larger turns than would fit in the bumps.

Why bumps then? Upper body rotation in the bumps is a guaranteed loser every time its tried. I believe things started breaking down on one leg for me because the turn dynamics/speed and my strength to maintain balance and effect the right tip/pressure. With that in mind, upper body rotation/counter rotation had certainly crept in.

Which came first, the chicken or the egg? When the turn dynamics would allow for tip and pressure, I am pretty sure that upper body rotation was not the turning mechanism but, how can I be certain?

If tip and pressure was the turning mechanism then there is ligitemacy to what HH says. In all practicallity though, tip and pressure seems to have its limit built around conditions and be a much weaker turning force than independent leg rotation. Tip/pressure seems to be more energy efficient while independent leg rotation seems to be more effective and unavoidable in the long run. This greatly increases my understanding of the relationship of tip/pressure and blending independent leg rotation.

For a living I am and inventor and as an inventor I will not jump to conclusions that there was no upper body rotation in the effort to make tip/pressure/ski design a concrete turning mechanism. Certainly in theory the idea should work but human bodies don't always follow theory. I will be convinced if I can ski easily on one foot with no poles through the bumps while feeling good CM release, tipping and pressure with tip engagement to turn the ski. Until then I am only 97% convinced HH is also right.
post #5 of 14
you a ****ed up guy pierre and I mean that in the best way possible.
post #6 of 14
Thread Starter 
Quote:
Originally Posted by BushwackerinPA View Post
you a ****ed up guy pierre and I mean that in the best way possible.
You appear to be in the 97% majority according to my latest observation.
post #7 of 14
Quote:
Originally Posted by Pierre View Post
There are also those who say that rotary is passive and totally unecessary for skiing. If that is the case, then one footed skiing should also apply.
Do you (they) mean it is "passive and [intentionally adding rotary] totally unnecessary"? Or that rotary is total unnecessary - regardless if it originates passively or actively? ...and, further, are you saying that statement concludes that rotary does not occur when one footed skiing?

In any event {whether on one leg or two}, to say "rotary happens passively" is not the same as saying "it does not occur"! Agreed?

Quote:
Originally Posted by Pierre View Post
cgeib I know... what you are fishing for...
Good thing one of us knows!

I think exploring the potential interaction of the poles is fair, don't you?

I understood your initial post to indicate using the poles you were successful and when you discarded them unsuccessful. And, knowing your analytical background, I'd have expected you to mention if any other variables changed. Right? If the only thing that changed is the poles, then it's logical they played a part. No?

Quote:
Originally Posted by Pierre View Post
For myself, I am not convinced there is not a way to tip the ankle and release the CM into the new turn in such a way that the technology in the ski is the turning force and not some upper body rotation. One ski skiing is the only sure way to prove this.
This "technology in the ski" being the sidecut and flex allowing it to decamber and scribe an arc in the snow, yes? Yet, you indicated you were "...making round buttered turn[s]".

Isn't it fair to ask "How you buttered those turns?" "What is the technology in the ski that butters a turn?" "Why does it only work on icy conditions with poles? (how does the ski know if you have poles or if it is now slushy?)"

Isn't it fair to question whether the icy (near frictionless) surface allowed you to reposition or rotate your ski to compensate for inaccurate/incompatible movements/direction of the ski and core ...in comparison to this option being restricted when the ski sinks into the slushy (high friction/suction) surface later?



Quote:
Originally Posted by Pierre View Post
Why bumps then? Upper body rotation in the bumps is a guaranteed loser every time its tried.
Why? Because it's a dang pain to get the timing of that winding/unwinding and sluing around to workout properly with the frequency of the bumps, eh! Of course, a lot of people force it to work if they have a pole to stuff in the ground now and then

Quote:
Originally Posted by Pierre View Post
Outside of the bumps I can feel this tip/pressure/tip engagment in slightly larger turns than would fit in the bumps.

Why bumps then? Upper body rotation in the bumps is a guaranteed loser every time its tried. I believe things started breaking down on one leg for me because the turn dynamics/speed and my strength to maintain balance and effect the right tip/pressure. With that in mind, upper body rotation/counter rotation had certainly crept in.

Which came first, the chicken or the egg? When the turn dynamics would allow for tip and pressure, I am pretty sure that upper body rotation was not the turning mechanism but, how can I be certain?

If tip and pressure was the turning mechanism then there is ligitemacy to what HH says. In all practicallity though, tip and pressure seems to have its limit built around conditions and be a much weaker turning force than independent leg rotation. Tip/pressure seems to be more energy efficient while independent leg rotation seems to be more effective and unavoidable in the long run. This greatly increases my understanding of the relationship of tip/pressure and blending independent leg rotation.

For a living I am and inventor and as an inventor I will not jump to conclusions that there was no upper body rotation in the effort to make tip/pressure/ski design a concrete turning mechanism. Certainly in theory the idea should work but human bodies don't always follow theory. I will be convinced if I can ski easily on one foot with no poles through the bumps while feeling good CM release, tipping and pressure with tip engagement to turn the ski. Until then I am only 97% convinced HH is also right.
I'm not clear where HH entered the picture here? Nor what position of his you are attempting to validate or invalidate?

I thought your question became:
Quote:
Originally Posted by Pierre View Post
My question now becomes Does release of the center of mass facilitate a round turn or does a round turn facilitate the release of the center of mass?
Anyway, I'm not sure at this point what I'm responding to or why. In the end, I guess I can simplify my prior post to:
How were you buttering/shaping your turns on one ski/one legged through the bumps?

After reading your reply, I think it boiled down to you saying you were ultimately using rotation, even though you were trying not to? (though I'm not certain)
post #8 of 14
Thread Starter 
cgieb I think you may have pointed me to my own answer by bringing up these questions.

I started out to work on subtle center of mass movements and simply overlooked the obvious when relating to round turns.

I was able to do the one leg sking on the flats with slush but not in the bumps. There were ruts in the slushy bumps that simply stopped my ski while the center of mass continued. Of course the turns were not round and of course the movement of the center of mass was interupted. Not because of turn shape but because of mechanical stoppage. The poles simply kept me upright and when both feet were on the ground I simply had more balance dah. I guess I did not realize this at first because the soft dynamics of these turns were such that the turn just stopped with no noticeable jarring when I hit the wall on the side of the rut.

The answer of course is that release of the center of mass facilitates a round turn. Interupting the center of mass interupts the round turn. The subtle movements that I was working on would have worked fine without the ruts.

I will answer some of your other questions when I don't have many exciting things going on. There is no way for me to concentrate right now which is probably the reason I confused you in the first place. Work has gotten very interesting and the stakes are high. I need a break and that will happen next week in Colorado.
post #9 of 14
I think that difficulty with one ski skiing is often because the ski is not being unweighted at the beginning of the turn. In icy conditions this is less of an issue because the ski can slide across the the hard surface of the snow. As the snow becomes softer this is more difficult.
post #10 of 14
Pierre,

Moving the CM over your feet is hard for many skiers in the bumps. Pivit-slips are a good drill for moving the cm into the new direction. If the skis form a small wedge during the pivot, the cm is not moved enough to release the edge. As for rounding the turns, after releasing the edge, your ankles must be open to turn the legs easily. Do pivot slips from a tall. open ankle stance for easy leg rotation.

While skiing bumps, if you are retracting while changing direction (over a bump), keep your sholders back so your ankles are open as you retract, move your cm and pivot your skis while you extend.

Your pole plant should be close to your foot to allow room for your skis to turn and allow better allignment as you move your hips to release.

Too bad you wern't here today, 4" new soft snow over packed bumps (the coral ice will come soon enough).

RW
post #11 of 14
How about keeping your center of mass stationary and moving your feet or foot in this case under the center of mass?
post #12 of 14
Thread Starter 
Ron that is pretty much what I teach.
post #13 of 14
Have a great trip to CO, Pierre!
post #14 of 14
Peirre,

Quote:
Ron that is pretty much what I teach.
Nice to know we are on the same page. Enjoy your trip!

RW
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