What You'll Need
A bench and a set of dumbbells make the world go round. Or, maybe just this exercise, but hey.
Why You Should Be Doing This Exercise
Great isolation work that will challenge your chest, shoulders, and arms. Well, perhaps that makes it a little more than isolation work, but its a nice change of pace for those less crazy about doing standard barbell bench press reps all the time.
Lying face up on the bench, and grab a set of dumbbells and extend your arm above your chest. Your palm should be facing forward, i.e. towards your toes. What should I do with my left arm, or the arm not holding a dumbbell? Good question. Its really your call. Either keep it up in the air or close to your chest, but make sure you're holding both weights in your hands throughout the set.
You'll want to extend your arm up without locking your elbow out as you alternate between arms. This will require you taking your time to ensure balance. But you've committed to yourself, so you've got time. Once you've extended one arm, repeat the movement for the second arm.
On the way down, don't allow your lovely elbow to drop past your shoulder. In other words, your elbow should be at 90 degrees with your shoulder, and no lower. And once there, it's time to hold and then press that weight back up.
Alternating dumbbell bench press is no joke. Your body will want to compensate for its lopsidedness, and do all sorts of odd things. Resist and use your core to compensate Keep your feet planted, keep your back on the bench, and don't lock out your pressing arm. Got it? Cool.