Not really, most of the top 800 guys are certainly not from a sprint background, Bucher and Coe being two obvious examples.
43.5 and 46.5 is a straight bullshit comparison, Merritt has never run 43.5, his PR is 43.75 then only two more sub 44 (43.96 and 43.98). ALL of these have been either in a major championship or later (he has come close to sub 44 pre this but again nowhere near 43.5), not early season or coming off high training loads. His season best pre world’s this year was 44.50, and he has not broken 44 this year.
SOME 800 guys can hit sub 46 at this time of year off MUCH higher volume training, other 800 runners will be 46mid which is about the same difference to the next tier of 400 guys who will be lucky to open in sub 45 early season and look to get below this by the major champs. To say a true 3 sec differential exists (43.5 vs 46.5) is simply untrue, it is more like 1.5sec maybe 2sec at a real stretch.
I do not think that 1 month of mileage running for merrit is responsible for any success/insuccess…just a small part of yearly training
Exactly, and weekly hour long road runs or long reps 600m+ for a general prep part of the year may not be such a problem for 400 guys looking to break 44, given what some middle distance runners with a fraction of Merritt’s talent over 400 can do with a program devoted to this work and with little focussed sprint training or speed background.