1. Lie face up on floor, holding a single dumbbell in front of chest with both hands, elbows bent out to sides.
2. Bend knees out to sides and place soles of feet together.
3. Crunch up, lifting shoulders and heels off floor a few inches.
4. Maintaining crunch position, pass dumbbell to left hand and extend left arm across body to reach dumbbell to right knee, rotating torso to right as you go.
5. Return to center crunch, pass dumbbell to right hand and repeat (extend right arm across body and rotate to left) to complete 1 rep.
6. Do 20 reps, alternating sides, without lowering shoulders or heels to floor until finished.