I have also trained for a sprint triathlon. However, about a month before the event - my right knee decided we weren't going to be running anymore. The ortho surgeon I worked with told me he could scope it & perhaps clean up any soft tissue damage in the joint - but I'd be out of work for about 6 weeks. Cause - I am also a nurse. I couldn't afford to take that much time off & even if I went forward with the surgery, the outcome was iffy. And for sure, I wouldn't be recovered enough to compete. It was basically a case of, "Doc, it hurts when I do this!" to which the doctor replied, "Then don't do that!" I still swim & ride my bike. But I walk instead of run these days. :)