Custom running workouts based in times

Hi all, I used to train running using based in times custom workouts but I thought that zwift didn´t permit design (even editing manually the zwo file) this kind of workouts for running. You can design time based workouts that finally are transformed in a distance based workout.

Recently I have viewed in zwift new running workloads based in times:

  • example: in the “less than 30 minutes to burn” section, we can see “Down and up the Ladder” running workout.

As you can see, this workout has designed its intervals by times. If you put your mouse pointer above the first interval, you can read “8 minutes warmup (or similar)”.(as far as I know it´s no possible to download a .zwo file from a non-personalized workout to copy the structure of the .zwo file, isn´t it?).

Then, if it existes this possibility, how could we create our own personalized running workouts by times?. I understand that the creator of that running workout must use a determinated structure in the .zwo file, isn´t it?.