In 2001 I did the London marathon. I'd never done much running before, and looking back it was a silly thing to have done. Inevitably I pushed myself in training and so injured myself 3 weeks before the big day. I still "ran" the marathon but was in pain from about 2 miles in. I spent part of the time halucinating I was up a mountain because I was in so much pain!!
I've often wished I'd done it as a walking marathon rather than a running marathon. I don't think I would have been much slower and I would have enjoyed the training and the event a whole lot more.
If that idea appeals to you, I've just published an article on how to prepare to walk a marathon:
http://www.sportandme.com/docs/sports/walking/guide/walking_marathon.html
happy walking!
