The most boring choice would be "section", and boring might be good here.

We could borrow from military strategy, not for the first time, and call it a "maneuver". More sporty, and pointing to the repeating nature, would be "round".

I wish the word "sprint" could be used for "this will call for an unsustainable amount of effort. we will be calling in dinner a few times. this isn't normal, and can't be normal, and everyone gets to rest after, but it's something we have to do".

Instead it's just a way of saying two weeks.