In reply to Doghouse: A stress fracture..
There is too much emphasis on not DNFing.. look at the ludicrous reactions to Radcliffe..
She's seen as a failure.. look at the comments when she retired.. yet she ran 2:15.. fastest woman ever..
We are in a ludicrous position where we'd rather never DNF than run good times..
I had a welsh coach say to me 'ultra runners never quit'.. which we do.. all the time.. we just learn from it and run faster next time..
Bigger picture.. bigger picture.. the moment your long term running is underthreat DNF.. its very very simple..