In my program, CNA skills were taught but not emphasized. First, we learned skills such as rolling and lifting properly with mannequins in the lab. We are supposed to practice these skills in the clinical setting as we did our LTC rotation, but many people did a minimal amount of lifting. A common attitude is that it isn't a skill we would use much as nurses in the field, so it didn't matter as long as you skim through clinicals. My job requires me to frequently help the aide with lifting and moving bed-ridden patients. Personally, I'm glad I learned those skills.
I have an old back injury from a car accident a few years ago. Regular chiropractic care has helped immensely in keeping my spine aligned. I've also been known to get an occasional massage (some people use massage therapy on a regular basis, and may even get their insurance to pay for it). You are less likely to acquire new injuries if you can keep your muscles relaxed rather than being too rigid. I also weight lift at a gym in order to keep my body strong. It may not seem related, but it does help to stay in shape to keep your body working at its peak.