Same, based on what I’ve learned from FasCat plans and coaching. While on paper it doesn’t seem like a big difference, finishing up a workout at 65-75% (mid to upper z2) appears to have provided me with more benefits at very little extra ‘cost’ (in terms of recovery). Nothing I can prove, just telling you what I believe based on my training history.

if my last INSCYD test is accurate, 50% FTP clears about 0.35 mmol/l/min versus 0.45 at 68% FTP (my max clearance). And those work intervals accumulate about 1.2 mmol/l/min, so my quick math for Engeler’s 6x2-min with 4-min RBI is:

- 6 * (1.2 * 2-min - .35 * 4-min)
- about 6mmol/l of lactate accumulated at the end of 6x(2-min @ 117%, 4-min @ 50%)
- note: the last 4-min are taken out of the 22 minutes, leaving 18 minutes

which for my lactate estimates, 50% FTP is enough to clear that remaining 6 mmol during those last 18 minutes. So then I believe the question becomes about making those 18 minutes productive and not impacting subsequent workouts. Speaking for myself, in general that would be doing the work at endurance/zone2 power of 65-75% FTP and not at active recovery power of 50%.