Something I find interesting is how the body loses movement without you even knowing it. For example, when my low back was stiff and flat I automatically sat on the floor on my left side. I never gave it a thought but once I got better movement in my spine one night I sat down on the floor to play with my cat and plopped down on my right side. That's when I realized I had lost the ability to sit on the right side without pain. This time around my PT started me out with side planks. At first I couldn't see how they would help but now when I ski I using my right side (an issue that my instructors had worked with me on 4 yrs ago) and when I pedal my bike there is definitely more power coming from my right side. I'm also standing more on my right leg and my hip doesn't jut to the side as much when I stand on one leg. The plank on the right still needs work. I have to be very careful with squats as they can still irritate my low back. Oh, I also discovered I can do single leg squats. Not low but when I did them for PT a year and a half ago I couldn't do them without a fit ball and it's something I quit doing because they irritated my low back.