To begin, lie down with your back pressed against the floor or on an exercise mat (optional). Your arms should be fully extended to the sides with your palms facing down. Note: The arms should be stationary the entire time.
With a slight bend at the knees, lift your legs up so that your heels are about 6 inches off the ground. Contract your abs and bring your back slightly off the floor This is the starting position.
Kick both legs outwards, as if you were opening a pair of scissors. Bring your legs back to the center and cross them over each other (closing scissors).
Perform the scissor kick in alternating fashion, keeping your abs flexed at all times.