At first I thought that the 28:46 time was the average time for 10k and I said, damn that's fast, then I re-read and saw that 28:46 was the average 5k time.
I'm a little surprised at that time, I was never a star runner, yes I did get down to 4:12 for the mile and 14:44 for 5k in college and I started running as a slow, short, uncommitted freshmen in high school and my slowest 5k ever was 25 and change.
I ran the 25 and change 5k virtually untrained and post-collegiately I once ran a sub 20 off of three weeks of running prior to a race and zero miles logged before that three week training block. And also ran a 17:32 5k two years later off of 6 weeks of training prior to a race and zero miles logged prior to that training block.
I never thought that I was any good event hough I was seeded 7th in the indoor 3k at the Atlantic-10 Championships in college although I got injured prior to the race.
I never thought that my best 5k was over 14 minutes faster than the average 5k. Well I now think more of myself as a runner, which is great!