Good for you! I can only go really hard 2-3 times a week, otherwise I am physically and mentally too exhausted. Since I do not have much time, I have to use it in the most efficient way. Therefore the workouts are optimized on my personal power profile - I can give everything and get the optimal training effect.

Even better for you! Not everybody has access to such training methods. If they are not built-in in you training software, one has to find other solutions.

You are totally right! However, most of these workouts are just calibrated on the single dimension of FTP. For me either they are too intense and I break down before I can finish - or they are not hard enough, wasting my time.

Copy the *.zwo files into your CustomWorkout folder. you will then find the workouts under the "Custom Workout" section in Zwift. If the folder is not yet available, just generate one custom workout directly from within Zwift. It will be saved in the correct location.

The workout ideas came from different sources like Allen & Coggan and various scientific papers (see e.g. Most Effective Intervalls? by Dylan Johnson) There are now two ways to perform such workouts: do not prescribe any power at all for the intervalls and just let the athlete train based on feeling (apply the steady power you can hold for all intervalls) or you set the power to be applied with ERG mode of the trainer. The first approach requires good knowledge of the own ability and is hard to apply consistently, while the second approach requires accurate power setting. Otherwise the athlete will exhaust too early or not train hard enough. These workouts try to solve the problem for the second approach: based on individual power profile, the relative power-to-weight ratio of critical power and the absolute anaerobic work capacity (AWC) are used to calibrate intervall intensity (under the conditions to have overall exhaustion down to remaining AWC levels of 25% and total stress points of around 100 per hours - this means a really hard hour of workout without being totally wrecked-up). A quadratic solver is used to adjust intervall intensity. FTP is assumed to be 95% of Critical Power (see Karsten 2021 for validation of assumption)

There are free converters for the provided workout file format (e.g. at What's on Zwift?). Just upload your *.zwo or *.erg file and convert it to *.mrc or *.fit.