Lie down on the floor with your legs fully extended and arms at your side, palms on the floor. Your arms should be stationary for the entire exercise.
Lift legs up so that your thighs are perpendicular to the floor. Keep your knees together, bent at 90-degree angles.
While inhaling, use your core to pull your knees toward your chest. Move your legs toward the torso as you roll your pelvis back and you raise your hips off the floor. At the end of this movement, your knees should be touching your chest.
Hold for a second and move your legs back to the starting position while exhaling.