When i'm waiting in line at grocery stores, or waiting for a script at the drug store, bus stop, wherever, I hook one leg behind the other, and just stand on one foot.. Other people barely notice if you hook the foot just round the back of the ankle of the supporting foot..
You can feel all your tiny intricate supporting muscles and tendons firing one by one to keep you balanced.. Eventually they strengthen up and you can stand pretty much perfectly still on one foot for as long as you like..
The next step is to go up onto the ball of your foot while staying balanced.. Slowly raise up, pause, and then slowly down... Again, when you first do it you'll feel all your supportending tendons pulling one way and then the other to balance you. But eventually they all work together and you can raise up and down, or stay on the ball of your foot for any amount of time you like, without anyone even noticing (i.e. your not wobbling around everywhere like a retard)..
I just mentioned this one as I find myself waiting around, A LOT, and it's boring.. This distracts you a little, and strengthens many of your supporting muscles that contribute to your balance..
Bookmarks