Originally Posted by
Buffalobiian
No idea. What determines that? We had a match of speed that showed us lung capacity determining endurance. I don't know what you can do to lengthen time-till-muscle-cramp.
My point is that Miyata found a trick that seems to be easily replicated. You can't just copy the other girl because lung capacity is genetic. Miyata needs something that has a genetic barrier, or a technique that requires so much dedicated practice that others can't easily pick it up.
The anime portrayed it as if she only needed one night, if not a week tops to get to 30 seconds.