Are you talking about sessions sort of like Andrews +1, Bays, Boarstone +1, Cheaha, etc.? The workout text for those mostly talks about improving muscle fiber recruitment:
to increase muscle fiber recruitment in an effort to grow your muscular strength
increasing your ability to recruit additional muscle fibers in an effort to grow your work capacity and lift your sustainable power
increase muscle fiber recruitment in an effort to grow your strength capabilities
I’m probably not in the demo you want feedback from (non-racer, super low threshold power), but I sub 'em in for regular Z2 rides when I’m feeling feisty.