This move kills two birds with one stone: You'll get a great looking upper back and lean arms all at once! 1. Sit with your belly button pulled in and arms are your sides bent at a 45 degree angle. Concentrate on squeezing you shoulder blades together. 2. Lift arms up so the dumbbells are level with your ears. 3. Raise your arms straight up so that they are parallel with your back. 4. Slowly lower back to the starting position.