Stand with your feet shoulder width apart, and hold a dumbbell in each hand. The right dumbbell should extend down at your side. Your left arm should be extended up from your shoulder and bent at the elbow at a 90-degree angle, so your dumbbell is next to your head.
With your right hand, curl your dumbbell up and in toward your shoulder. At the same time, press your left dumbbell up over your head until your arm is fully extended.
Continue to do bicep curls on your right side while doing an overhead shoulder press on your left for 10 reps.
After completing your reps on one side, perform 10 reps on the other.