It is actually very difficult to drop out of the New York marathon, as I found out after six miles.
Everything was going along very nicely in the early stages, the thigh injury had settled down because I hadn't run the week beforehand and I was enjoying running with Paula Radcliffe's husband Gary Lough and friend Tony.
Then, out of the blue at six miles, I got a calf pull and thought I couldn't run. I actually sat down on the ground because of the sharp pain.
I had a wander for a medical tent and it is virtually impossible to go off course, largely because the crowds are incredibly deep even after only a few miles.
As it happened, I managed to hobble along again and got into a rhythm of eight-minute miles, which is pretty slow for me.
In the end I got round in three hours 27 minutes - about half an hour slower than I would have liked but not too bad.
The injury made me enjoy the event even more in some ways, as I was able to stop thinking about running and soak up the atmosphere.
The course wends through all these different communities and there are wall-to-wall spectators. It is phenomenal, it really is.
"The hype surrounding Lance Armstrong was really quite unbelievable"
I was met by Paula and Gary at the end and Gary wanted to know if I was all right but I wanted to know how fast he'd gone after he was bouncing along at the start.
He clocked two hours 41 minutes - a lot faster than I would have been capable of and a respectable time for someone who has been retired for some time.
Gary said he won't do it again but it wouldn't surprise me if he did because he ran well - though he will have his hands full in January when their first baby is due.
Hats off are also due to Lance Armstrong, who managed to dip under three hours.
He said it was tough and, even though he had some impressive pacemakers in the shape of Alberto Salazar, Joan Benoit Samuelson and Hicham El Guerrouj, he still had to push himself really hard.
The hype surrounding him was just unbelievable. I felt a bit sorry for the elite athletes - no-one knew who won the race but everyone knew how Lance had done.
I'm pretty sure he won't do it again - I think he realised he won't run much faster unless he trains really hard because even though he is a great cyclist the skill does not transfer that easily.
At the front of the field, Jelena Prokopcuka was a popular winner in New York. It was obvious no-one was going to go with her when she broke away. She is a tough character, the course suited her and she is one of the best around.
Brazil's Marilson Gomes dos Santos was a bit of a surprise winner in the men's race but I found out afterwards that in the pub the night before the race - and of course I wasn't in the pub the night before because I was tucked up in bed - one or two in the know were tipping him to run well and win.
As for me, I'll definitely be back. I'd love to have another go and I don't think three hours would be too much of a problem. I've been hobbling for a few days but can walk properly again now - so that's a start already.