1. Sit on an exercise ball with a 3- to 5-pound dumbbell in your right hand and a 5- to 8-pound dumbbell in your left hand. Straighten your arms and raise both at your sides to shoulder height. Bend left elbow so the dumbbell is parallel to the ceiling (as shown at right). Press your left arm up, straightening elbow. Then lower left arm to the starting position. Do 10 reps.
2. Switch weights to the opposite hands and do another 10 reps, leading with your right arm, to complete 1 set. Then do 2 more sets on each side, the first with 8 reps and the last with 6 reps.
3. Do the entire move 3 times a week, and you should see noticeable results in 3 to 4 weeksjust in time for sleeveless weather.