I know Kansas goes through a "hell week" at the beginning of practice. I know I always had to go through that for sports in high school too. Probably not a bad idea.
I went to a small school and was lucky enough to play football, basketball, track and baseball. The first week of basketball practice was the worst. Give me two a day football practice any time over the first week of basketball. Our high school had a ramp that connected the commons to the halls for classes. That ramp was torture for a week. Basketball uses so many different muscles. I agree, I don't think we need to concern ourselves with these guys having a baseline of fitness.
Also considering they are in shape I don't think 30 second 200s and 75 second 400s would be over taxing them to much. That said, it would be a ***** to complete.