Thanks for posting this. I'm registered for a marathon in November and dreading it plus looking forward to it.  I just ran a 10k with my 10 year old and he's done a bunch of 5ks but didn't listen to me when I warned him to pace himself. He left me behind -- and then I found him waiting for me at mile 3. He was pretty tuckered out and I ended up walking a lot of the 2nd half with him. It doesn't sound as challenging as it is.  At the same race, a 37 year old collapsed and died at the finish line. He was a pretty big guy and it was a hot, humid day.