We will now explore the problem of balancing while simply standing, walking, or turning.
To stand without falling means that the centre of gravity has to stay over the small rectangle between the toes and heels of the right and left feet. Bending, picking up objects, or shaking hands all move the centre of gravity.
Walking and running also involve momentum in the direction of travel. This momentum primarily affects the effort involved in starting and stopping.
Turning involves rotary momentum.