Philosophical advice:
So, if you establish a threshold pace for workouts, in order to progress over the season, do you tend to increase the distance of the threshold at a given pace, OR do you advance the threshold pace itself? Specifically lets say 1500 runner. Your threshold pace should improve with time, but so will the distance you can do a given threshold. What do you guys use a rule of thumb? Do you just use 20 min +/- as your distance and as you improve decrease the pace (faster that is)? (based on perceived effort/HR etc..).
I have my kid doing 3 or 4 or 5x 1k thresholds (as cruise intervals <1min rest ). As she tolerates these workouts, do i increase distance or drop the pace or a little of both. Im trying to think of it from the standpoint of the purpose of the work out. If the purpose is to always be at that threshold in threshold workout, you have to drop the pace as you improve? No?