This last year (2019), I began to figure out (due to instability in flexion and extension) that some of the exercises I was being proactive in doing were doing more harm than good. I got a new Medicare Advantage plan and requested Home Health Physical Therapy to teach me how to do the correct exercises.
I was right. I was told NO TWISTING OR SHEARING. This cut out a chunk of exercises I had been doing.
No situps or pelvic tilts. I was taught how to do abdominal bracing (tucking my belly button to my spine), bottom squeezes, squats using both while holding onto my sink, slow marches while sitting (with abdominal bracing), and some others.
No stability ball exercises. It would be too easy to 'rock my boat' of spondy.
No leg extensions (kicking back).
A walker can't be used as a wheelchair. Brakes must be on when sitting on the seat.
No traction. I had an inversion seat. Since the area is unstable, traction is never a good idea.
I also had to modify upper body exercises due to nerve compression in my right shoulder. Whenever I raise my arms above chest level, make sure my thumbs are facing up. Palms down rotates the shoulder and compresses the nerve.