I also had L4-L5 degeneration in discs, and one herniated disc. Every week Physio worked with movements and techniques designed for strengthening the core muscles. I was weak before THR from living in the pre surgery out of shape stage.This was the strangest exercise and helped so much. I'll try to explain it in case next time you go to PT ask about it if interested. A movement pressure gage was placed on my stomach kind of like a round tire Gage with needle to measure on the numbers for movement. While laying on my back knees resting on pillow, I was instructed to squeeze my glute and stomach muscles without making any movement that would show up on the gage on my stomach. This took a lot of muscle control and once I learned how to move each muscle in the bum,back & stomach area it becomes easier and strengthens all the core muscles and the lower back. The best muscle exercise for my back was sitting in a chair or laying flat knees supported and flex those glutes and start with 15 glute and stomach squeezes move up to thirty repeat 3-5 X's a day. It was like magic. After a few weeks my back was so much better. Also did massage and acupuncture and water exercises for strengthening back muscles and legs & also helps with IT band issues as I had all those little micro tears in mine . It all eventually comes together. As the saying goes practice makes perfect. So true...