Hip abduction with isometric extension against gym ball (Hip abduction with extension rolling ball up/down against wall, in side lying; 01)

Lie on your good side with your back to a wall and your affected leg on top.
Bend your bottom leg for stability but keep your top leg straight and in line with your body.
Place a stability ball against the wall behind your top leg.
Push the back of your heel into the ball against the wall.
Lift your top leg up and roll the gym ball up the wall.
Make sure you do not roll your body forwards or backwards.
Return to the start position and repeat.