As you know, the sore butt is the process of it healing from the workout, so it will get better.

The knee might be a concern. When I had knee pain, my doctor told me to do leg lifts while on my back, lifting only a short distance. I never would have guessed that that's what I need. My knees give me difficulty descending stairs, so I should try that again. I was diagnosed with chondromalacia when I was 24. I'm about to turn 65, so I guess I've been doing well so far. The pain has never been severe as far as I can remember. My iphone tells me about my stairs climbing. It shows that I go up faster than I go down. I bet the high school students think I walk like an old man. Well, I am an old man.