I walked most of the half, and most of the full. My training was sporadic at best.
The important thing to remember is that the last person to cross the finish line gets the same medal as everyone else.

You have to maintain a 16 minute mile (although there is a little fudge factor built into that) or they "sweep" you off the course. I have to say, I was at the very back of the pack for mile 17-20 of the marathon (at which point I lost my companion and picked up some speed) and the "sweepers" were all super supportive and encouraging.
Someone else can probably give you a better sense of what it would take to actually *run* the 13.1 miles. But highly recommend it. Wonderful experience--except for the year it snowed

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