There's reported cases of children and even grandchildren of polio survivors having similar symptoms of polio without having contracted it. One of the symptoms are aches and pains in the joints, and that's what I have. I've always had aches in the back of my knees, and occasionally in my elbows, and I can't run for very long without getting tired out quickly.
Looking this up, I think this is Post-polio syndrome. I hear there are ways to treat this, but I don't know what those are. I've been finding interesting articles about it, though. It's a pain (ha) to deal with when it presents itself, which is rare these days since I graduated high school, but I'm not one to complain. Even then, as long as I'm not over-weight or having heart problems, I'm fine with what I do. Seems to work for me just fine.