Start: Lie on a bench with your head, torso, and hips pressed against it and your feet spread wide and flat on the floor. Grab the barbell with a full overhand grip. Place your hands slightly wider than shoulder-width apart., remove the bar from the uprights, and hold it with straight arms over your collarbone. Pull your shoulder blades together in back.
Finish: Lower the bar, slowly and I control, to just above your nipples. Then press it u and just slightly back so it finishes above your collarbone again. Stop just short of locking your elbow, and keep your shoulder blades pulled back.
If lower-back discomfort is a problem for you, put your feet up on the bench, or lift them up in the air. Even if you have no back problems, this is a fun variation to try; it requires more balance and forces you to maintain an abdominal contraction throughout the exercise.