Ya, when I was recovering from surgery, the elliptical really helped. Started off only doing a few minutes slow before my back would tighten and my foot would go numb, but it was easy to progress slowly. I think it is because it really works your hips without much impact. After a couple years I could finally do HIIT on it again.
Yea I think keeping the hips moving loosens up the back. I'm going to try as long as I can to stay away from weights. I want to see if my back will heal any further. I have been stretching my hamstrings a lot, which also seems to help.
Today I just did:
Pullups 5 sets to failure
Dips 3 sets to failure
3 min warm up on row machine
17 mins on stair master (intervals)
Bird dogs
Curl ups
Side bridges (love these)