Step 1: Lie on the back with legs extended.
Step 2: Bring both knees in so legs are at 90 degree angle. Hold for 1 count.
Step 3: Push out through heels to starting position in controlled manner.
Tips: Keep the legs parallel to the floor the entire time. Don't let them flail up and down (core is all about controlling the movement). Keep the lower back flat against the ground by not letting up on the core and keeping the shoulder blades lifted from the surface.
Link™ to Exterior: Attached to external anchor
Stance: Lying on back. Legs fully extended