Lie on your back with your legs stretched out in front of you, your hands on the ground out to the sides or beneath your lower back to make the move a little easier. Pull your abs toward your spine, trying to get your spine and lower back to touch the ground as much as possible.
Raise your legs toward the ceiling so they form a 90-degree angle with your upper body, or as close as you can get.
Lower your legs back down until they hover about an inch off the floor, or as close as you can get without your lower back lifting off the floor. Keep your neck relaxed and your lower back on the floor.
This counts as one rep. Repeat for two sets of 10 reps.