Polorized, how focused?

When doing a polorized training leading up to a race block. Is is better to focus on only one energy system for the interval workouts (ie only do MAP intervals for both of your hard workouts each week), or is working on multiple energy systems acceptable (doing one day at MAP and one day upper ZN 4)

map and z4 should be pretty much the same thing. adding sprints will give you a stimulus of the top end (PCR). however, that energy system will not improve much. it will make your type 2 muscles stronger.

For the high intensity stuff I would focus on what appears to be more relevant to your race and maybe also consider time of the season.

In winter as I am also riding on the track, I focus more on 3-5min efforts and also add sprints. Closer to the grand fondo season I drag myself into those 16min and more ones.

Listening to Seiler and looking at the research it doesnt seem to matter all that much physiologically, but I feel mentally its really hard to stay on for longer intervals…