These seem to fall into two camps, either stuff like 4x4, 5x4 or very short 30/30 or 40/20. What's the consensus? One kind a waste of time? Or both equivalent and good to interchange.
If this time last week someone would have suggested doing 1.5 hrs low end Z1 I would have thought they were taking the ... However, todays session was exactly that. Trust in the coaches / process !! Hope everyone manages to hit todays goals.