Deep core in bent knee fall out ("Knee fall out" Core/abdominal stabilization, supine; 03)

Lie on your back with your knees bent and your feet flat on the floor.
Place your hands on your lower tummy, just inside your hip bones.
Gently tighten your tummy muscles.
You should feel your back flatted on to the floor.
Do not hold your breath.
Allow one knee to slowly fall out to the side.
Do not allow your back or pelvis to move.
Control the movement as you bring the knee back up to the starting position.