QuickChick wrote:I will let Holly answer for herself, but I would think it would be because most trail races aren't exact distances- for example the 5 Peaks races have distances like 12.6km. Or because they're weird distances, like 28km, or because the courses are so distinct that the wouldn't compare to another course with the same distance. You could probably think about pb's for each race, though, when you're comparing each race to itself.
Yeah, all of the above.
There's more than an hour difference between my slowest 50k and my fastest 50k, and they're both faster than the 44k race I did. If I were to run 50k on a road it would be faster (but way less fun).
Lots of people will count their pb for a specific course... that's about as specific as you can get though!
And for me, personally, the time it takes me to do a trail race is secondary to the race experience.