Pushing against two walls makes arms float... how?

i’ve never done this myself, but people say that if you stand in a hallway or something for a while and press against the walls, and the put your arms down, they’ll float. so, how does this work?

Don’t know. I just spent 5 minutes looking like I was trying to hold up the house.

My arms didn’t float. They didn’t feel like they were floating.

So, how long are you supposed to do this?

If there is something to this, I imagine it might be similar to how I feel like I’m walking 20 miles an hour after I get off a treadmill.

The trick is to stand with your side close to a wall or doorpost (your hip maybe 30 cm away from it) and try to push yourself away from the wall by pressing with the back of your hand against the wall. Keep your arm straight. Your whole arm should feel the tension.
Keep this up for one or two full minutes.
Then step away from the wall, and relax your arm, let it hang limp at your side. After maybe 20 seconds, it will raise itself in the air without conscious effort, as if flying up by itself. After maybe 10 seconds it will come down again, but the effect is quite funny.

Now go try it, and tell me if it worked!

The explanation is that your arm has adapted itself to the "counterpressure"of the wall. When that counterpressure is gone, the arm overcompensates and lifts.

And when you do this in a doorpost, with both arms, then of course both arms will “fly up”

Or how about the clenched fist over a finger for 30 seconds followed by slowly opening the fist.

Oh wow. I had completely forgotten about that for the last like… fifteen years.

"clenched fist over a finger "

I take it you mean putting your left forefinger inside your right fist, through the right forefinger and thumb, then squeeze?

I tried that, nothing happened.

Your hand should lock up.

That happens to me when I carry heavy things (like pieces of a drum set–I hate living with drummers!)