From the crunch, come back to the tabletop position with your legs lifted, knees directly over your hips. Bring your knees and feet together.
Press your arms and lower back into the mat.
Keep your big toes pressed together, and open your knees up wide like a book. Then bring your knees back together to complete the rep. Picture a string attached to your belly button pulling both knees in and out.
Continue for a minute, making sure your lower back is imprinted into the mat, performing about 20 reps.