Trust me, that's back tension shooting with a thumb trigger style release..........and as good as it gets form wise. (Not to mention perfect bow balance as well geez) You're hand compresses the instant the release trips.....it's just relfex.
Look at how still everything is at the explosion of that shot. No head movement, no grabbing the bow, just straight forward , straight back motion of the opposing forces of bow arm and release arm position.
That's BEEAUTIFUL.
I mean he doesn't even blink. You think he's done that a time or 2.[:-]
Dave is shooting a Carter 3 finger "Just Cuz" or "Target 3" I think the hand movement you are seeing is him settling in on the release getting his pinky in position, from there it's just pulling through.
That's the precise form that I try to emulate in my shooting......still working on that.