Rehabbing the lower back by... Bill Starr
I started doing this routine after injuring my lower back (muscle injury) and found it made all the difference in how my back felt the rest of the day. I still try to do a short version in the morning or as part of my warmup.
If I'm going to be back bridging, I warm up further with a few sets of deadlifts, 3-5 reps at about 80% of my 1RM. I'm not sure why, but my lower back gets really unhappy if I don't.