John Wesley Harding wrote:
In spite of his age, Farah ran 59:07 at the GNR in 2019. I realize that is a net downhill course but I still think the track would prove faster for a runner like Farah. At his very best, I believe Farah could have pushed this record toward 21,500m. Not that Haile couldn’t have run even further at his best—it’s a weak record.
I bet he runs 21,340, about 59:20 1/2 marathon pace, and breaks the record by 55m. As likely as he’s a cheater, he’s surely a professional and reliably shows up in good form.
You could be right but I think a significant factor that people are ignoring is the ability to relax in a half marathon on the roads. You can settle in and just keep rolling for 8-10 miles without thinking too much.
It's easier mentally; you run with a pack for 3/4 of it. That also makes it easier physically in terms of drafting.
You have a changing scenery (this is a real factor) which helps keep tedium at bay and motivates you to push.
And it's easier in terms of physics as you are running roughly in a straight line Vs 400 corners.
It will be very difficult to stay on pace past lap 40. Basically needs to run 67.5 the whole way. I think he will start slipping into 68s and 69s by 45 minutes.