Step by step instructions
Lie faceup on a mat or bench with knees bent and hip-width apart and feet flat, holding a dumbbell with right hand. Extend arm up to the ceiling in line with right shoulder, left arm extended down by side, bracing abs in tight.
Bend right elbow to lower end of dumbbell across body toward left shoulder (try to keep right elbow lined up with right shoulder). Return to starting position. Repeat on opposite side to complete set.