There are already a lot of good comments here. Just keep moving is #1 for just about everyone. I would also add make sure you are eating a healthy diet and you are getting enough high quality protein. Your muscles cannot repair and rebuild without good, high quality, balanced protein. If you need help with exercises for your back and for your legs, it might help to see a PT and/or a trainer. If that is not in the budget then walking can do miracles. Start with small amount and keep adding a little bit a day, and/or just try to go a little bit faster every day. You might want to break the walking up into small amounts, but more times per day, for a while. I hope this helps.