I suspect that ultra endurance is somewhat different from the other sports. It seems reasonable that conditioning requires loading mileage like crazy, even compared to marathon or triathlon. Maybe microcycles (1 week) are unnecessary.

Modern preiodization was scientifically discovered by Russians in the 60s and it seems to work in every sport when correctly applied. Do you have have mesocycles (2-5 weeks) or macrocycles (6-12 month) in your training plans?

https://en.wikipedia.org/wiki/Sports_periodization