Bekele's 5K (12:37) or his 10K (26:17)?
Will someone not named KB run 12:37 first or 26:17 first?
Is sub-13 harder or sub-27 harder? Despite the 5K record being only 23s faster than 13, whereas the 10K record is a whopping 43s faster than 27, I see that sub-13s have happened many more times in history than sub-27s (223 times vs. 66 times, according to
http://www.alltime-athletics.com/men.htm
). So this seems to indicate that sub-27 is harder.