AT had scheduled this workout for me this morning Engeler
When I checked out the intervals before jumping on the trainer, I was surprised to find that the final portion of this workout is 22 minutes @50% FTP. 22 minutes of a one hour fifteen minute workout. That seemed strange to me. I would have gone crazy! Opted to do Monadnock -2 instead.
Can anyone shine some light on why this might be?
Not unexpected to tag on a bit of endurance work after the intervals, but 50% would be too low (I’d be looking for 60-65%).
Could be a design error.
I don’t have any special insight into why TR selected that workout…but I can tell you why I’d ask an athlete to do that: to make sure blood pH normalized post workout (or, to make sure lactate was cleared from the blood). That would be more with an eye on tomorrow’s workout…no so much because 20 minutes at 50% ftp is going to cause adaptation.
Most non-pro athletes are going to clear 0.4 to 0.5 mmol/l per minute or something like that? So there is not going to be enough time between 2 minute intervals to clear accumulated lactate. Even if you are sitting at 10mmol/l at the end of the intervals 22 minutes at 50% ftp is probably going to get you back down to less than 2mmol/l or something like that.
So that would be one reason…but it’s probably not the thought process here. I presume you’re next workout is probably an endurace workout. 
It’s Sweet Spot actually. My workouts have all been prescribed by AT 
Thank you for your response. That would make sense and the ‘clearing’ process does seem like the logical reason.
are you in specialty? or build? Since AT was announced, TR introduced a lot of workouts with less stress. Rather than clearance - which tends to be solid z2 - my WAG is that the workout has easier recovery while still providing some maintenance/stimulus as you enter the final phase of building up to an event.
What’s strange about this workout? This seems inspired by polarized workouts, the additional time at 50 % at the end is to improve endurance while not adding too much training load. I reckon that similar, but harder workouts (in the sense that they will have a higher VO2max progression level) will have you work at a higher percentage of FTP at the end (65 % and up).
With Monadnock -2 you spend a few minutes above 50 % FTP at the end, but then you also spend some time between 40 and 50 %. It seems pretty much like a wash to me between the two workouts.
Maybe I wasn’t clear in my original post. I was questioning the need for 22 minutes @50% FTP when the work has been done. This might be where I’m missing a deeper knowledge of workout structure.
For me, and I do appreciate that we’re all very different, I don’t want to be spinning away on the trainer for any longer than absolutely necessary. That’s why I opted for Monadnock -2. Six VO2 intervals, 2 minutes, roughly the same percentage, boom! Job done. Once the intervals are done, that’s it for me. Workout done. 22 minutes @50% FTP is a waste of time, in my opinion.
That was until @Brennus gave me another perspective
I’m in the second week of the Build Phase. I did wonder if AT had introduce a few POL workouts but then I remembered that POL is still experimental and I don’t believe it, or the workouts, are included…?
Just looking a couple of weeks ahead, I also have this on my calendar EMMA
For clarity, I’m not saying these workouts are rubbish, I’m just trying to understand them better
Those are for your aerobic endurance and very much part of training. It makes you more efficient at in the higher zones and allows you to recover faster, for example.
It could be there for the extra clearing, but if I were prescribed this workout I would probably just manually bump the last 20min from 50% to ~65% so that (A) I actually have some resistance to push against and (B) I get similar cool down/recovery but with a hair more of an endurance bend.
Two thoughts:
22 minutes of any aerobic training, once, is a going to be a waste of time. But 22 extra aerobic minutes at the end of your intervals, twice a week, for fifty weeks a year, is an extra 36 hours annual endurance training. In exchange for very little except the time - probably no extra fatigue indeed you might feel better based on @Brennus point about lactate, and no extra effort in setting up/breaking down/laundry/mixing drinks/all that - you’re already sitting there, warm in your kit. I wouldn’t get up earlier and miss out on sleep or food for it, or upset the family by taking more time on a workout than you said you would, but the version of yourself who trains 36 more hours a year is going to be fitter, long-term, than the version who doesn’t, right?
there are tons of threads on here about fasted/low-glycogen/depleted/whatever protocols e.g. getting up first-thing to work out with no breakfast. Don’t know if you’re interested in that at all, and would depend on what other training and eating you’d been doing across the weeks, but I’m pretty sure that after 6 x 2 mins @ 117% FTP you’ll have depleted glycogen to a meaningful extent by the time you start that work at 50%. So maybe a more worthwhile stimulus than first meets the eye.
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:
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%.