I am not of the same ilk as the others posting here but I have read over many threads and had opportunities to apply what I have learned. Just a brief synopsis of some quick relevant tips germaine to your posts
When you think of 2-3 wk blocks of time also consider how many meters your athletes are running in total, per intensity categories (hi-lo-med), recovery between hi-intensity days
400 M Relay work is part of your hi intensity meter tally. If you have an athlete that is also multi-event, LJ, TJ, etc, the speed they use on approach, drills, all serve as short speed work and therefore tally up as well.
Just because an athlete has their regained their wind during relay reps or sprints doesn’t mean that their CNS is ready to fire again. When they say they are ready for another rep, give em a bit more time.
A couple thoughts on speed endurance- 1. coaches sometimes think speed endurance is only achieved by placing reps one after another. The idea is to develop the ability to maintain one’s top end for longer durations. When athletes fatigue after a couple of close reps they are increasing the threshold but what percentage of their true top-end speed are they maintaining. Its similar to when a coach has an athlete do “killers” on a basketball court and call it speed endurance. After they run a couple times (acceleration included) they are not working speed anymore, just the duration of that pace.
If you have less time for GPP then its okay to extend GPP into the season so as long as you aren’t expecting quality performances all the time. Your athletes, for the sake of their confidence, must understand to some degree that they are under load. Use meets as a speed endurance workout with quality tempo (ON GRASS in flats if possible) the day before and after the meet. This is for their health.
Hope this makes sense