Not An Expert
This is one of those things that really shows the difference between absolute world class runners and the rest of us. I don't think that I could ever, even at my most fit, run 8 x 1k @ my 3k pace w/ 5:3 (work:recovery). That's what a long period of high-level training will do for you: allow you to handle these sort of workloads which in turn allows you to run world-beating times. The workout Ramzi describes, even watered down to my own pace with the same recovery ratio, is damn impressive-something I could write down on paper for a workout plan, but never complete.
I think the closest to this I've ever come is 8 x 1000 @ 5k pace w/ just less than equal recovery (this was hard, but not a race effort).