Fartlek, my foot!
Tonight's track workout was all of forty minutes of fartlek running: around the track for forty minutes sprinting the first forty yards of each straight and jogging the remaining 320 yards of the track. I managed fifteen minutes before my insides turned to intense jelly balls of pain. I stopped for a minute to let the balls disappate before running around the fields and finding a couple dogs to chase for my sprinting - much easier and far more fun to chase.
I'm not sure what's so special about the first fifteen minutes of a long distance run. I had a very similar problem last week, running the dish: bad cramps at the beginning of the run, only to have them disappear after a minute break, and a good run following. This has to get easier. I can't keep running like this and not have it get any easier.