I run half marathons, several a year. Beginning in December I had my second toe begin to hurt half way through the run. THis seems to happen each time now....once in January, twice in FEbruary, and on a 10 mile run today. In addition, I have been finding myself incredibly fatigued just a few miles into the run .....today I walked on the 10 mile run. I don t believe that I have ever had to stop and walk during a race, but did a few weeks ago on a training run too.