2.5 ウェイト・チェンジについて

 

解説文

 

2.5 On Weight Changes

What is a full weight change? Does the non-weighted foot have to come off the ground?

Not necessarily. But if there’s so little weight on it that I *could* lift it, or move it, without any problem, i.e. if my other foot is providing all of the support for all intents and purposes, that’s a “full weight change” even though the non-weighted foot isn’t off the ground.

Many beginners haven’t learned to sense whether or not they’ve really made a full weight change. Sometimes it’s helpful to make them pick up the unweighted foot to force them to transfer all their weight (or else fall over). Better dancers know how to slide their feet horizontal to the floor with essentially no weight (or a controlled amount of weight, depending on the dance).

In some absolute sense, contact implies some weight. However, at dance speeds, the less than 1% of a person’s weight remaining on the moving foot is essentially insignificant with respect to the overall forces moving them about. And I would call the moving foot non-weighted if there isn’t enough pressure (really force) on it to move the dancer a noticeable amount (maybe just enough floor pressure to keep a dollar bill under the moving foot from getting left behind).

We are really incorrect to think of this in static terms — the weight transfers to the other foot and then back again. There is a brief period in there where it is *possible* to lift the foot off the ground with no additional “weight transfer”. The point is to not “slur” it — there should be a definite transfer of *almost all* weight, or none (as in a touch or point), but not in between.

Whenever we work on “grounding” my instructor says that if you don’t do a full weight change (or none) you are part-way over one foot and part-way over the other — which is never where you want to be. Now pay attention: One of the things we are very big on in teaching our WCS is that “&” steps are never steps where static balance is achieved. In other words, you don’t really stop and rest your CG over an “&” step. The “&” step is simply a transition to get you from the foot you are on back to the same foot.

You can put ALL your weight on one foot for a short period of time without having your CG directly over that foot. Try it.

  Stand completely on your left foot.
   Put the ball of your right foot on the floor about 6 inches back without weight.
   Press into your right foot hard enough to pick your left foot completely off the floor and slip forward about an inch without bobbing your head or body up and down. 

Congratulations. You have just done a “ball change” with complete weight change (or you wouldn’t have been able to pick up your left foot without bobbing down and up) but without your weight being over your foot (because your right foot was behind you and you moved forward.) This is completely within the laws of Newtonian physics. The only limitation is that the time your weight can be on the ball of you right foot is limited by knee and ankle flex, since your body will accelerate away from it. But if the music is fast enough, then the “ball change” will happen within the time of a comfortable amount of knee and ankle flex and body motion. This is why certain dances only feel comfortable at certain tempos.

And this is a problem with teaching dance. Where your weight is and where your center of mass is can be different when changing your direction of motion (accelerating). Try to explain that to a dance newbie. Let’s take for example the leader’s footwork on a whip: side-together-side, L-R-L.

When the man puts his weight fully centered over the left foot, then shifts weight to his right foot, in order to move his center over his right foot, he has to stop and reverse the direction he is traveling in. Try it. Stand in front of a mirror. Stand on your left foot. Then shift your weight to the right foot. Your center moves slightly to the right, doesn’t it?

If the man does this on the L-R-L triple, he teeter-totters from side to side and ends up looking robotic. What he needs to do is CONTINUE MOVING HIS CENTER to the left, in which case his “&” step on the right foot will not quite reach his center. ON THE OTHER HAND, for followers doing the run-run-run on a side pass, of course, the center is over the “&” step. The rule is not that the center does or doesn’t stay over the foot. The rule is, your center is what travels the smooth path. You don’t stop and reverse the direction of travel of your center just to get it over the foot.

There are plenty of examples of where it is appropriate for an “&” to be not directly under your center. There are also plenty of examples where it WILL be under your center. Most instructors teach that if you can audibly hear the anchor-in-place in WCS that you are being too severe in the weight changes.

出所：

2.5 On Weight Changes

What is a full weight change? Does the non-weighted foot have to come off the ground?

Not necessarily. But if there’s so little weight on it that I *could* lift it, or move it, without any problem, i.e. if my other foot is providing all of the support for all intents and purposes, that’s a “full weight change” even though the non-weighted foot isn’t off the ground.

Many beginners haven’t learned to sense whether or not they’ve really made a full weight change. Sometimes it’s helpful to make them pick up the unweighted foot to force them to transfer all their weight (or else fall over). Better dancers know how to slide their feet horizontal to the floor with essentially no weight (or a controlled amount of weight, depending on the dance).

In some absolute sense, contact implies some weight. However, at dance speeds, the less than 1% of a person’s weight remaining on the moving foot is essentially insignificant with respect to the overall forces moving them about. And I would call the moving foot non-weighted if there isn’t enough pressure (really force) on it to move the dancer a noticeable amount (maybe just enough floor pressure to keep a dollar bill under the moving foot from getting left behind).

We are really incorrect to think of this in static terms — the weight transfers to the other foot and then back again. There is a brief period in there where it is *possible* to lift the foot off the ground with no additional “weight transfer”. The point is to not “slur” it — there should be a definite transfer of *almost all* weight, or none (as in a touch or point), but not in between.

Whenever we work on “grounding” my instructor says that if you don’t do a full weight change (or none) you are part-way over one foot and part-way over the other — which is never where you want to be. Now pay attention: One of the things we are very big on in teaching our WCS is that “&” steps are never steps where static balance is achieved. In other words, you don’t really stop and rest your CG over an “&” step. The “&” step is simply a transition to get you from the foot you are on back to the same foot.

You can put ALL your weight on one foot for a short period of time without having your CG directly over that foot. Try it.

  Stand completely on your left foot.
   Put the ball of your right foot on the floor about 6 inches back without weight.
   Press into your right foot hard enough to pick your left foot completely off the floor and slip forward about an inch without bobbing your head or body up and down. 

Congratulations. You have just done a “ball change” with complete weight change (or you wouldn’t have been able to pick up your left foot without bobbing down and up) but without your weight being over your foot (because your right foot was behind you and you moved forward.) This is completely within the laws of Newtonian physics. The only limitation is that the time your weight can be on the ball of you right foot is limited by knee and ankle flex, since your body will accelerate away from it. But if the music is fast enough, then the “ball change” will happen within the time of a comfortable amount of knee and ankle flex and body motion. This is why certain dances only feel comfortable at certain tempos.

And this is a problem with teaching dance. Where your weight is and where your center of mass is can be different when changing your direction of motion (accelerating). Try to explain that to a dance newbie. Let’s take for example the leader’s footwork on a whip: side-together-side, L-R-L.

When the man puts his weight fully centered over the left foot, then shifts weight to his right foot, in order to move his center over his right foot, he has to stop and reverse the direction he is traveling in. Try it. Stand in front of a mirror. Stand on your left foot. Then shift your weight to the right foot. Your center moves slightly to the right, doesn’t it?

If the man does this on the L-R-L triple, he teeter-totters from side to side and ends up looking robotic. What he needs to do is CONTINUE MOVING HIS CENTER to the left, in which case his “&” step on the right foot will not quite reach his center. ON THE OTHER HAND, for followers doing the run-run-run on a side pass, of course, the center is over the “&” step. The rule is not that the center does or doesn’t stay over the foot. The rule is, your center is what travels the smooth path. You don’t stop and reverse the direction of travel of your center just to get it over the foot.

There are plenty of examples of where it is appropriate for an “&” to be not directly under your center. There are also plenty of examples where it WILL be under your center. Most instructors teach that if you can audibly hear the anchor-in-place in WCS that you are being too severe in the weight changes.

Back to table of contents.

Go to the next section.

Go to the previous section.

This file is part of the lead/follow FAQ list. These are articles compiled from the newsgroup rec.arts.dance by Mark Balzer. Html-isation by Victor Eijkhout, victor at eijkhout dot net. See also the Rec Arts Dance FAQ list Copyright 1996/7/8/9 lies with the compiler, the maintainer and the contributors of various parts.

You may link to this page and make copies for private use in any form, but reproduction in any means, including book or CDROM, is not allowed without permission from the copyright holders.

It goes without saying that the maintainer and compiler of this FAQ take no responsibility for any inaccuracies in the information presented here or for any use or abuse of this information. They are neither a doctor nor a lawyer.