What is?

Hey i have question. What is the diferance betwen “special speed” and “speed endurance”. Well i allready know what speed endurance is but i dont know what special speed is.

Speed: 0-8 seconds
Special Endurance I: 8-15 seconds
Special Endurance II: 15-45 seconds

Speed | Alactic Power: 0-7 seconds
Speed Endurance | Alactic Capacity: 7-20 seconds
Special Endurance 1 | Lactic Power: 20-40 seconds
Special Endurance 2 | Lactic Capacity: 40 seconds- 2 minutes.

I don’t go by distance because every athlete is at different stages of development and what is SE I for one athlete might already be SE II for another as far as distance is concerned.

Thanks for the answer.