Lie down on a bench, your feet resting comfortably on the floor. (If you don't have a bench you can use a step, or you can lie flat on the floor.) Grab your dumbbells and extend your arms toward the ceiling, shoulder-width apart, palms facing away from you (so that the dumbbells are positioned directly over your shoulders).

Bend your elbows about 90 degrees, gradually lowering the weights until they are above and a little beyond your shoulders.

Now push the dumbbells up with an arcing motion until they're back in the starting position.