The motion is not merely slow but controlled - all areas interplay to create a constant state of tension. However, the head and neck are essentially still and motionless. To achieve this and avoid unnecessary movement, the shoulders, by contrast, should be relatively relaxed. When the heels are drawn slightly in before stepping forward, the balls of the feet remain "stuck" to the floor, creating additional torque and tension. Movement both forward and (especially) backward is led by the trunk or hips, not by the legs or arms.