Why does holding your hands up, help you balance?

Question

I just thought about that, why?

Answer 1

It changes your center of gravity.  Keeping your arms out allows you to adjust the position of your arms, and thus adjust that center of gravity more easily (i.e. when you swing your arms around when you lose balance)

Answer 2

actually, what it does is allow you to move them to counter some inertia, as you start to lean.

having them straight out allows you to move them up or down, to counter some rotation, without changing your center of gravity, left or right, and having to also think about that change also.

if you were to hold them straight up, over your head, (A) it would be less comfortable, but more important, (B) when you moved them, it would counter the start of a lean, however, your brain would also have to calculate the change in the center of gravity, since your hands were no longer equally distributed from one side of your body to the other.  so, it's just easier for you to do the mental calculations if your hands are held out to the sides.

another thing to think about, is sometimes you twirl your arms, to regain your balance.

what's happening then is, when you get off balance, your body begins to circle around the spot where you feet contact whatever you're standing on.

twirling your arms is an effort to counter that rotation.

and your brain has to figure out how much to counter the rotation, and actually make you lean a bit the other way, so that when you stop, the stopping process restores you to standing straight up.

cool, huh.