The use of 120 bpm has plenty of scientific evidence supporting it. Most coaches can't cope with that idea though, they think the rest has to be 2 minutes or something and that MORE is better. Physiologically these workouts might work, but in a mechanical world they don't, the runners breakdown and never recovery. Tempo work is lactate work, extensive or intensive, it just ends up being the degree to which you work the system. I would be in department of saying you overtrain your athletes. 10x300m for 400m runners at this time of year is crazy. When will they approach 3000m even in race conditions? Why jog when you should be doing some sort of dynamic flexibility or mobility between? "Bring the muscle heads back closer together" what the heck is that supposed to mean? Are you talking sliding filament theory with A and Z bands? "Flush the toxins out", what toxins and be specific? I no longer believe in mileage, I see it hammered in to young runners today and they break. I believe in adequate stimulus for adaptation and I think that is intensity based.
Learning how to glide? That is a momentum idea and belongs in a speed-endurance or maximal velocity session not a workout that is intensive tempo.