OK, and I generally stay in good shape also. I used to be able to grab a full breath of air and sink in the pool.
1) I start with leg lifts, 6" high and bring the knees to your chest. Then I keep the legs straight and go 90* up (vertical, or a little past). (I've currently worked up to 20 of each) with sneaker on. If you have trouble with it, do it w/o shoes at first.
2) I do knee bends. When my back was still in pain I put my hands on a high piece of furniture to help keep my back straight and not strain it. I don't need to do that now. 30 seems to be enough. (The hands on the furniture was my idea, but my PT guy loved it).
3) Stretch your back and neck (be careful with this until you are feeling better). I start by arching back as much as I can, then I stand facing away from the wall and turn my neck as far as I can one way, then the other. I do 3 sets.
4) I then do push ups - had to start slow because of an injured shoulder, but I'm currently doing 25-30. A few years ago I could do over 60.
5) I then do leg stretches. Hands on a waist high piece of furniture then one knee forward and bent, the other straight back, do a few sets.
That is it … no equipment required and only takes 5-10 minutes. I do them after I get up, with the TV on, on a carpeted floor.
My brother started doing the same routine after I told him about it, and we both agree it seems to help a lot. A good deal of this was developed with my PT guy.
Good Luck everyone, and Happy New Year … back pain sucks!