A simple "move", but quite difficult! Place your hands wide on an exercise ball, starting with your feet close to the ball. Step your feet back one at a time until you are at an incline, keeping your arms straight. Try to keep your body straight, and not in a pike position. The harder you want the isometric hold to be, the further your feet want to be from the ball. Try it and see! Gradually try to go for longer periods of time.