if you are referring the test/challenge that was by invite only for the actors training for the movie 300, then it was a test/challenge not a workout they did periodically. it was motivation to push every one harder so they could get invited to do it.
the idea was to time how long it took to complete the entire 300 reps. not to time how long it took to do each segment. you can read about it from the people that trained the crew:
and top quote a small part of that article for those that dont want to read it all:
The second misconception surrounds the idea of the Spartan workout, aka "300", how frequently it was done or who actually finished it. "300" is a one-time test, an invitation-only challenge undertaken by those deemed ready for it.