Great rehab program. I am a 50-yr old mother of 3, I eat healthy and am not overweight - but I don't exercise other than occasional walking. I had a non-existent core. :) My lower back began hurting more and more...when I'd wake up I could barely bend over. It became a burden to even unload the dishwasher, get clothes out of the dryer, etc. I'm 50, not 90, I thought, so here I am doing RehabZone. Best purchase ever - I would be paying THOUSANDS for physical therapy which I'm sure is what my doctor would've recommended. I am on phase 2, workout 2. I feel strong now (a feeling I've never had) and can easily bend over, do household chores, yardwork, weeding, hacking down bushes, etc. All the things I used to do. I feel like I just got a new lease on life. I LOVE that the videos don't just focus on your abs, which is what I thought "core" was. There is arm work, leg work, shoulder work...the videos really do tone your whole body. I do the workout faithfully 3-5 times a week before moving on to the next one fot the next week. The videos start slow and weren't overwhelming for me. They're about 20 minutes...who doesn't have time for that, when you're investing in your health and your body? You are up and down a lot, so if that's difficult for you, you may have to hit pause. Also someone with knee problems may have a problem with the up and down. Give these a try - they were a life changer for me!!