Sounds interesting. I know "Cursor" was writing about the build-up program last year but honestly when you look at the program it seems relatively easy. Sure there is many kilometers of running every week but only at "easy" pace. As I understand it, "easy" should be th pace when you can still comfortable speak to another person the whole time, which in my case is about 135 bpm on average.
A question about 65% and 75% effort. Is it so that it is the percentage of your HR interval between HRmin and HRmax? In that case, since my HRmin is 62 and HRmax 182, those should be 140 (65% effort) and 152 (75% effort). do I get it right?