It's a simple way for you and the patient to feel and somewhat quantify how well the lateral chain can stabilize single leg stance. I use it after I have restored ability to load the lumbar spine according to the Lower Quarter Clinical Practice Patterns I teach in MMT Premium and Seminars. Lateral chain stability should be part of your stability phase of rehab after the patient is pain free, but before you're ready to discharge. If their is a difference, one of my favorite exercises would be unilateral Farmer's Carries with the kettlebell or dumbbell placed in the hand opposite the side of stability loss.
Let me know what you think!
blog post here https://goo.gl/n2PXrZ