Abs, Back, Chest, Core, Shoulders
1. Lie back on a bench holding a dumbbell with both hands over your chest. Brace your abs and pull down your rib cage, so your back doesn't arch.
2. Extend your arms behind your head until you feel a stretch in your lats, and then pull the weight back over your face. Make sure to keep your arms extended, without locking out your elbows.