Posture, and balance.

One of my bad habits when playing the theremin, is tending to lean forward at times, or slouching. The old fashioned posture training method of standing tall, with a book balanced on ones head comes to mind.

I usually find myself leaning forward if I make the mistake of looking down at the theremin, evin when using the tai-chee stance.

I seem to get better balance when keeping my head tilted back slightly, as if making eye-contact with people in the back of the room, in the back balcany, or looking at a wall clock.

I have to be wide awake and full of energy. If I'm tired I tend to sway and move arond way too much.

I sort of plant my feet and stand at a bit of an angle, keeping my lower body stiff while trying to keep my upper body relatviely loose and flexible.

Thomas, I tend to do the same... in my case, I think the impetus isn't looking down per se, but the temptation to watch my hand (not to mention a lifetime of mediocre posture).

I also wonder if my combined experience as guitarist, pianist, and conductor makes it feel thoroughly unnatural to keep my right hand at shoulder height. It tends to drift down toward waist level, and I have to concentrate to move it upward to mid-antenna level.

This is all true regardless of stance (firmly planted, tai-chi, or sitting).

As for fatigue: When I'm tired, my pitch stability and accuracy go right out the window, such that posture and balance are the least of my concerns.

One thing I've learned the hard way, is that if I slouch, I get tired very quickly. I have to give myself a mental nudge to get the posture right. On my practice schedule I can't let slouching happen if I want to get at least 6 hours of practice time in.

Letting that pitch hand drop too low causes you to have to fight gravity, and that will also wear you out quickly. I agree, a lifetime of techniques used in other musical disciplines can affect, at least for the near term, ones techniques on the theremin.

I suppose 30 years of choral singing in which one has to assume a singing posture may have helped me in this regard, I could be wrong.

I would suggest deliberately bringing your pitch hand much closer to your shoulder than you normally would for a while when playing to see if that helps train your pitch arm to stay where you want it.

Oh, Diggy, a few cups of coffee helps too. ;)

something that helped me from the start
was to play singing bowls standing up.
it got me balanced, standing grounded
through the heels, and in the zone.
now the theremin does that,
usually in a few notes.
i feel really lucky
for them both.

Thomas, thanks for the suggestion, which I'll try to hold myself to for the next month or so.

About slouching: Perhaps because my training as a singer is so far in the past (vs. comparatively recent yoga classes), what I find to work best is simply to fill my lungs with air. That is, if there's any resistance to doing so, it's a sign of muscles to loosen and bones to move out of the way... and most of all, to draw my head high and my shoulders apart, so as to allow the maximum lung capacity.

The trick, of course, is holding that open posture, even as the urge to control! control! control! the hand motions leads to an unwitting contraction of arms and torso and head. Still working on it...

I like that yoga method. That's a lot like breath control for singers. It does take time, but it eventually locks in.

Looking out is useful; and letting the head raise/float upwards and tilt slightly forward encourages the spine to lengthen and lift upwards; holding a backwards head tilt tends to promote imbalance with a leading/lifted chin, backwards arch in the neck and compression in the spine There's helpful info in the forums here in TW, and searching the web for info on violin or public speaking posture is helpful too;
it will def. help you out of bad habits.
It probably won't take too long and is well worth the investment. We are always constantly adjusting every hinge in our body as we play. I often revisit it and it's always refreshing.

Omhoge is right, I should have pointed out that you don't want to tilt your head back too far. I perform best when my head is level, or slightly tilted back. (Like Clara Rockmore), as it seems to provide better balance for me, anyway.