All You Need Is 1 Dumbbell For These 20 Intense, Muscle-Building Moves

Working one arm at a time makes the core work more to stabilize your torso while you work your chest.

• Lie on your back with your heels about a foot away from your butt. Hold a dumbbell in your left hand and bring both hands to the ceiling.
• Bend your left elbow, lowering your upper arm to floor. Exhale and straighten your elbow, pressing the weight back to the ceiling to complete a rep.
• Perform the same number of reps on each side.