SMH to those who do not know what an FKT is. LOL. But for those among us, it stands for "Fastest Known Time". The two key words being "fastest" and "known".
You usually have to pick a route that is a legit path (so me being the fastest to run from my house to the farm shop in Lower Shelton does not count, though I have filled in the forms to get funding to make it a national trail). You have to run it the fastEST, so not necessarily fast. And it has to be known, ie on Strava.
But what to choose? There are so many. The Pennine Way? The Bob Graham Round? The South West Coastal Path?
It would be more impressive if I set myself an FKT that no one had ever dared to do.
I have seen a few signs for the "Clay Way" on some trails near me. I usually steer clear, as they seem covered in this weird type of mud that gets really slippy in the wet and then dries into rock-hard lumps in the summer. It is great for making pots and pans but lousy for running.