Anyone knows if you want to, when you are sitting down, and angle the balls of your feet and angle your knee at a specific angle, you can get your leg to vibrate at a high speed. Anyone know what causes that?

You're probably pinching a nerve or something. I wouldn't make a habit of doing it.

(January 3, 2018 at 8:52 pm)Chad32 Wrote: You're probably pinching a nerve or something. I wouldn't make a habit of doing it.

No no no, I am not talking about personal maladies, I am talking about a specific angle when sitting you can choose to get your legs to vibrate at a high speed.

Well you know how some people tap their feet when they're bored? That's the cruise control.

Been sitting here twisting, dorsi-flexing, plantar-flexing, abducting, adducting. No shakes. I will try again in the a.m. after 3-4 cups of java!

google muscle fasciculation

If you get your leg in a position of unstable equilibrium, any impulse one way or the other takes a small amount of energy. Small energy inputs are easy to reverse, so the frequency can be fairly high. I'm betting that that "high" frequency is somewhere around 2, maybe 5 Hz.

For an example of unstable equilibrium, think of a ball at the top of a hill, exquisitely balanced so that the slightest impulse one way or the other will cause it to roll down the hill. Look at your leg(s) when they are in a position where you can repeat the motion, and notice how easy it is to make it go one way or the other. You are oscillating about a position of unstable equilibrium, most likely.

At my age probably arthritis.

I thought it was because I had weak-ass chicken legs

(January 3, 2018 at 8:45 pm)Brian37 Wrote: Anyone knows if you want to, when you are sitting down, and angle the balls of your feet and angle your knee at a specific angle, you can get your leg to vibrate at a high speed. Anyone know what causes that?

Reflex.  Kind of like when the doctor hits your knee with the little Fisher Price hammer.