To do the Peek-A-Boo, lie on your back and stretch your straight legs up toward the ceiling. Reach your hands back overhead if you want then let your legs open up to the sides as if moving to do the splits. As your legs open up, crunch up and reach your hands through your legs. Crunch your shoulder blades up off the ground. Lower back down and bring your legs back together. Keep your legs as straight as you can the entire time. Repeat crunching back up as you open your legs back up. Beginners can bend their knees or leave out the upper body crunch and just perform the leg portion.