Disclaimer: non-physicist!
In the anatomical literature, they refer to one hertz as a complete cycle of the movement. e.g. Extend your elbow, then flex it back to the starting position — that’s one hertz. If you’re a hummingbird, flap down, flap back up to the starting position. And so on.
Of course in picking terms, each directional half of the movement plays a note, so you get two notes for every cycle.
In the lab tests, they chose a take where John happened to play around 11hz - 12hz. And I believe they averaged over several seconds somewhere in the middle of that take, as his movement is slightly different both before he gets going, and after he begins to tire. You can see a bit of that footage at the end of the trailer we put up:
In the clip I posted upstream, I just picked a one-second interval somewhere in the middle of one take of a batch of practice footage. I would guess John’s actual speed probably fluctuates somewhat throughout that take, and across different takes.
The greater picture we’re seeing here, particularly when compared anecdotally to the drum contests, is that the 300bpm ballpark — give or take a couple notes per second — is probably close to the limit of human performance for deliberately actuated muscle movement.
