1. Hold a 5lb dumbbell in your right hand and stand next to the bottom step of a staircase or a sturdy stool.
2. Step up onto the step with your left foot and raise your right arm to the side until it's parallel to the floor.
3. Lower your arm and step down. Repeat for a total of 15 reps on your left side.
4. Switch sides for another 15 reps. To get your heart pumping, do three sets on each side without resting. Do the move three times per week for best results.