Alex,
HIIT A is straight forward. From #1 to #21 it goes from 20/40 to 30/30 finally to 30/15’s in 1, 2 or 3 sets and 6, 8, and 10 reps.
What is the purpose behind HIIT B? The logic doesn’t appear as straight forward as understanding HIIT A. It is also not used in any of the Coach Jack plans.
Dave
Hi Dave, oh my… 
A complete oversight? I will have to revisit what it was supposed to be and fix it.
Alex,
Sorry, I didn’t mean this as critical in anyway.
As we talked about previously I’m going to do fun outside rides until it gets cold out in northern Illinois. I’m reviewing options for what to do after that.
I thought the Coach Jack HIIT A/HIIT B may be options for intensity levels that would allow for growth while not being so hard that I can’t recover adequately / lead to burn out.
Dave
Oh no sorry Dave I was trying to be funny with the faces… HIIT B is totally not right (BROKEN) and I need to fix it. It’s been this way since the beginning and no one said anything. It’s not the end of the world, meaning many platforms do odd sequences and this would still likely cause results but as you know we just try to keep ours very systematic / logical in our progressions. Originally we designed HIIT B very logical but somehow I never inputted the data correctly.
Yes 2 HIIT a week can be a reasonable solution for your needs. I will see if I can’t get it fixed soon. It should not take too long.
Oh, I just reviewed again and I was wrong. HIIT-B are correct, I just looked too quickly.
They are more typical 30/30s but just progress in the number of intervals. They are also lower intensity and focus more on total duration. I believe they get harder faster than the HIIT A.