Hi! Here's the deal- I was born with some issue in my left knee and when I was 6 I had surgery. It has bothered me throughout the years. So last July I was doing Power 90 and I injured my knee while doing lunges/ squats. It didn't hurt at the moment, but I could feel something was "wrong" so I stopped doing the workout. Well, within about 5 hours I was in significant pain. So much, that I went in to see my Dr. He said everything is fine, if you're not better in 6-8 weeks come back. Well, I wasn't better in 8 weeks so I went back and he again said I'm fine. The knee joint feels stable and I probably just "agitated" my knee. His advice was to not do anything where my knee is bent and I'm putting weight on it. So...no lunges or squats at all. I tried to find an alternative, and what I found were my stairs! I put one leg on the floor, and the other on the 2 or 3rd step. I bend my front leg, making sure my knee doesn't go beyond my ankle, and it's a nice little modified lunge. Well, as of this morning, my knee started popping while I was doing that. That is bad. It doesn't hurt now, but I have no idea if this is going to hurt in a few hours. Is there anything else I can do? How do I work those muscles without doing the lunges or squats? Would walking up and down the stairs get the same benefits (or something close)??? I really want to continue my workouts and make progress, but my silly knee is wussing out. Help? Thanks!