Yeah, unless your doctor really understands what you are about to undertake, I would listen to your body. About 30 years ago I had a doctor that also did IMs. With him, it was a straightforward conversation since he "understood". One time I sprained my ankle really bad (stepped on a door handle in the sidewalk) his statement was "You should not run on this, but on the off chance you decide to ignore me then you should........" We both knew I was going to run on it and he wanted to make sure I didn't take any additional risks".

Good luck in the race!

Mike