Breaking into the mid 15s would be…
Just out of interest. I was looking at the record time for various age groups on the concept website. There are only 3 times that dip below 16 minutes:
Event – Category-Name ——— Gender — Weight — Age — Country — Record —- Season
5000 – 30-39 – Rob Waddell —– M —— Hwt —– 32 —- NZL —– 14:58.3 —- 2008
5000 – 19-29 – Matthew Pinsent – M —— Hwt —– 25 —- GBR —– 15:11.0 —- 2000
5000 – 40-49 – Nik Fleming —– M —— Hwt —— 40 —- GBR —– 15:57.6 —- 2009
Now, I’ve not heard of two of them but I seem to remember the middle one was a bit handy in his prime, so yeah I reckon sub 16 minutes would be pretty tidy.