I think THIs wrote:
McMillan calculator is useful, but shouldn't be used as an indicator by any means. It reallllly depends on your training and what kind of runner you are.
I was a 14:25 5k guy (focus on 5/10k), which says I should have been at:
1:51
4:09
8:12
when in fact I only ever ran:
2:00
4:17
8:18
Could I have run 8:12 and 4:09 by training for it specifically? Yes, I think so. But I was always doing 10k training. I could never run under 1:56 though probably, I just don't have the wheels for it.
However, this also predicts 29:56, 1:07, and 2:20 and I ended up doing 29:34, 1:05, and 2:18.
this ^ !
some people are naturally quicker, some people are naturally more strength/endurance based.
besides, you are only what 9 seconds over the course of 3 miles? so out of 1000 seconds (16 minutes x 60 seconds + 40 seconds) you are only "off" by 9 - mcmillan seems pretty darn accurate to me...