Aargh. That's not a speed-endurance situation. I really don't want to be argumentative, and caveat -- I am not even close to being an expert. But I don't get why everyone keeps using that term for anything related to maintaining a faster than jog pace.
Workouts examples likely needed for OP:
- Weekly long run. Starting out as LSD long slow distance run, build up to 90 min, once per week, about 1 min/mile slower than easy pace. With fitness, build up to 30 sec slower than easy pace, then over time run at easy pace. Eventually, make it an 80/20 progression run with the last 20% at steady-state pace aka light/moderate tempo pace.
- 5-8 x 1000m @ LT pace with 2 min jog, done nearly every week for 1-2+ years.
- 8 x 400m @ current mile pace, with 400m jog, working down to, say, 64 sec over time, then increase reps to 10 but back off rep pace to 66, then working rep pace down to 64-63-62-etc over time. Done every week, each year after base phase, right up to peaking / late season when it's time to back off volume and sharpen.
- 5 x 80m hill accelerations. Done weekly during base phase. Walkdown rec, 3 min total rest.
- 5 x 60m, run as "flying 30's". Done weekly up to mid-season. 5 min walking/standing.
- 4 x 150m in spikes @ 400m effort on the curve, faster down the straight. 5+ min walking/standing. IMO, OP should aim for 17-18.x sec, without a full sprint effort off the line. Eventually down to 16-17. Done mid thru late season.
Of these examples, only the last one is speed endurance.