"the 30 and 40 age groups tend to outperform younger runners"
Source on that? This seems to show the opposite: https://marathonhandbook.com/what-is-a-good-marathon-time/#:...
Source on that? This seems to show the opposite: https://marathonhandbook.com/what-is-a-good-marathon-time/#:...
That's Strava data and also tracks with my personal experience, no idea where that site get's its data from.
Here's some particular data from Boston, NYC and Chicago also bearing that out.
https://www.runtri.com/2012/01/marathon-finish-times-by-age-...