What a great addition these have been. Having done 2 Intermediate 12-week plans back to back I was starting to lose motivation and then it was suggested to do the Building Blocks.
And what a difference: did a 3 week block for sprinting and now on a 4 week FTP block. Really enjoyable and now feeling really refreshed and raring to go on a new 12-week plan starting December.
Really recommend these mini plans and, while still hard, I actually feel stronger now then when I started them.