Leg scissors is an exercise which is an attempt at working the lower
abdominals. In addition to the lower abdominals the hip flexors are worked
extensively. Since the leg scissors exercise is technically a hip flexor
exercise your mental focus is going to determine whether or not you work your
lower abdominals more than anything. In order to work your lower abdominals as
much as possible make sure you keep your lower back in contact with the floor.
This can be done by making sure your pelvis (hip bone) is rotated posteriorly
(not arched). Keep your core drawn in and mentally focus on working your
abdominals and make sure you keep your legs off the ground high enough so your
lower back does not come off the ground but low enough so you can feel the burn
in your lower abdominals