Pop that depends on age and illnesses. Like if you have bad knees, weight lifting isn't for you. If you have back problems, walking, weight lifting and so forth can cause more damage than you already have.I had a tech come over so he could help with some physical therapy and he ended up messing the stimulator that's in my back up. He told me 5 reps and they hurt but I was determined to do them. I ended up in bed with a broken lead in my back for a week+. So my deal was I had a therapist that didn't know what he was doing and I was too dumb for not stopping. I also told him about the stimulator and the leads. (the leads are long wires). You have to know whats good for you. Exercise cause wasted muscles to firm back up but the wrong kind can set you back.