I just had an idea: maybe some of the stuff you see in the John Wick movies (particularly 2 & 3) is kind of a good representation of high mitochondrial fitness? Like that The Quick & The Dead book?

Then again, maybe it's aerobic? I heard that that's what gets someone back up to speed when they get tired.

I know, I know: "Focus, determination, and pure will." But if we're taking fitness & physically how that sort of ability would be built, what do you guys think it would be?