Block periodization, comment my plan

I’m interested in your plans here. Plan Builder has me going SSB1>SSB2>SusPB>SSB2>XCM Specialty

I was thinking about replacing the Base 2 from just before Spec with a VO2 block.

Why do you guys go five workouts week one then only one per for subsequent weeks?

Have you found your muscular endurance to decrease as a result of a VO2 block? And if so, how have you countered this? Should I include one long SS workout per week (90% 2*45min or something along those lines)?

search for Block periodization - its a periodization approach that got good results in some studies by doing this. It’s not for everyone and has a lot of risks and potential returns, so worth a read of the original study and what some of the experienced coaches say about using it.