Brian MF Sell wrote:
No one has mentioned the GOAT blue collar runner Brian Sell!
Dude couldn't break 10 min for the 2-mile in HS. PR of 2:10:47 at age 29. At age 30 runs 2:11 to finish third in the 08 Olympic Trials and goes to the Olympics.
Dude didn't train in HS.
The difference in most of these examples are is that they aren't of guys who trained hard from 15-35 and were like 2:12 (i.e. Sara was a national class runner for a long time) marathoners. And then over the next 2 years they went from 2:12 to 2:07. We have lots of examples of talented guys who took the sport up late and ran fast in their late 30s/40. See like John Campell or Jack Foster.
If you go down the US marathon list there are some people who said their PRs in their mid to late 30s. But a lot of them were running either close early on or just moved to the distance.
You are going to need a combo of a person being good enough at short distances to stick with it (i.e. you are running like 13:25 5ks and think you are on the edge of breaking through) , the ability to up training (going from 80mpw to 110 if what I read is right), and then it turning out the longer distance is your event. That combo isn't going to happen much.
If you expand to look at late 20s guys, there are a bunch that went from OK 10k guys (call it 29 mins) to much better marathoners (2:12) when they switched up their training. But obviously that isn't quite the same. They are younger and not as high of level.