I don't know if he's doping - I hope not - but talk of sub 1:40 is certainly insane, and his progression does need explaining a little bit. I mean, presumably he was already wearing super shoes in 2021 or perhaps 2020. The thing is it is odd that NOBODY here mentions Arop in doping discussions, even to the extent of the mods deleting posts and threads that do bring up his progression.
So age 19- 21 he went from 1:45.25 to 1:44.14
Age 22 to 24 he went from 1:43.26 to 1:42.85
Age 24 to 25 he went from 1:42.85 to 1:41.20 and now people say he can run under 1:40 at age 26 or 27?
If it does happen, then he is the most obvious doper of all time, and if he isn't, it's because he is Canadian and has a disarming grin.
Another thing is he is absolutely huge. If he wasn't a runner, I'm sure he could switch to at least a light-heavyweight boxer. Yet he is 'gaining confidence in the 1500m'.
At the start of the EPO era, all of a sudden you had 1500m men able to run world beating 5000m times, when just a decade before the likes of even Walker and Ovett had struggled to a greater or lesser extent.
Now all of a sudden 800m guys, even stocky or well-built ones, are able to run world class 1500m times. Perhaps something similar is happening?