Speed Endurance specifics

For an advanced athlete, will speed endurance only be gained by sprinting at or very near top speed for the desired distance ie. 80 to 150m or can the following scenarios still aid?

  1. sprinting under an already fatigued state but still attempting to sprint at top speed eg. with little rest between reps

  2. sprinting up a slight incline ie. 10 degrees or less of sufficient length to induce fatigue

  3. performing SE1 in an attempt to gain speed endurance

There is a place for most approaches but moving into competition readiness, I’d say 3 is the only way to ensure speed is in place. Just being fatigued is only a guarantee of being fatigued.
Concept 1 might work if it fits the description of a split run within the parameters of 3. An example would be 60+60.

Thanks Charlie, and actual speed endurance of 150m or below would be better than SE1 during competive season, CNS fatigue issues aside?

Just another consideration, outside of the actual distance and effort of the rep(s) -Mechanics has such a vital part to play in speed maintainance: Therefore having the strength in place to maintain the structure under the pressure of fatigue is basic. Apologies if I’ve missed your point or diverted the conversation.

I was really meaning that although Charlie stated point 3 would be the most reliable out the 3 points, speed endurance itself would be better than SE1 but that may sound obvious.

However, relating to “having the strength in place to maintain the basic structure” was along the lines I was meaning ie. by using the 3 points to describe other ways or by way of a foundation to gain speed endurance.