It was a benchmark routine they used in training. Something to they essence of "I was able to complete it" I wouldn't call it a routine to do at all.
I'm extremely impressed with the training they did, but it was to look good really, nothing to do with baseball.
Quoted from link at the bottom:
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. By the end of our four-month project 17 people had done the workout (Logan and I were two of them). This constitutes about 50% of the cast and stunt crew. We supervised every test, evaluated each rep for quality and only counted those that achieved our standards for form and range of motion. Like many workouts “300” is not hard once you’ve done it but the apprehension built up ahead of it – something we encouraged – was enough to make some guys fear it to the degree that performance was compromised. This workout was a crucible that some passed through and others still have hanging over them.
25x Pull-up +
50x Deadlift @ 135# +
50x Push-up +
50x Box Jump @ 24” box +
50x Floor Wiper @ 135# (one-count) +
50x KB Clean and Press @ 36# (KB must touch floor between reps) +
300 reps total
Article can be found here: http://www.gymjones.com/knowledge.php?id=35