I’ve recently learned about the value of long threshold intervals e.g. 2x20 or 1x40 @ FTP.
Almost by definition, at the end of a threshold (read: Steady state) interval, I’m usually not cooked. I’m capabable of punching out 1-3 minutes at 110-120% VO2 max depending on how I paced the interval. Particularly on the last interval of a set where I don’t need to worry about saving myself for the next interval.
Is it beneficial to actually do so? I figure why not add some VO2 max adaptation to the back of a threshold workout if I can. But I’m not sure if adapting the two energy systems simultaneously makes physiological sense.
One obvious alternative is to use those same energy reserves to push 2-5% above threshold power for the entire duration of the interval, but I feel like the psychological toll of this is much higher, as it’s the difference between spending 30-40 minutes at MLSS and 1-3 minutes above it, and probably literally spending about 30-40 minutes at increasingly high lactate levels above MLSS. The ‘roll on’ of pain over a long period is pretty mentally crushing.
The other alternative is to just not do any VO2 max work in the FTP interval, thus saving yourself for the next days workout, but if real life forces more than adequate levels of recovery, that’s not always useful.