I am a gastroenterologist and I have also been a runner for over 40 years. I started running when I was in medical school and had run nonstop since. I retired about three years ago and I started running more than ever. I ran so much that I actually ran a hole in my left knee. I saw a surgeon and he felt that it was not an operative situation, but I had no way of really getting relief from the discomfort, and I was really limited in terms of what I could do.