I would say Last if for them, just finishing the race wasn't the goal.
First may go through more pain but has the adrenaline flowing and the thrill of winning is amazing.
I have been first a few times. I have been last or two or three places from last too...
Definitely, it was more often harder to finish towards the end - except, again, when just finishing was the goal. Then, I would mind finishing after last :d