I find I have the opposite problem: after playing some Theremin (which requires very fast, precise movements, but otherwise very little strength), my hands are too jumpy and jittery to do much of anything else.
I would guess there's a series of limiters, filters, negative feedback, stuff like that -- in the path between motor cortex and muscle. With proper training (and a bit of warm-up or meditation to refocus), I expect you are exerting control over those systems -- which allows you to do very precise movements, or very large movements, but not usually both at the same time.
It's not merely analogous to, but directly the case that, you are changing the characteristics of the servo system; different amounts of open-loop (fast, imprecise; requires lots of practice to pre-compensate) and closed-loop (precise, slower; incorporates proprioception as well as touch, visual, etc. sources) control, as well as the dial on how much gain we're working with (lifting takes strong activation signals, placing SMTs not so much).
I expect if there were a way to measure activation of these systems, someone like Bruce Lee would've absolutely pegged on all counts!
Tim
(Disclaimer: I am not a trainer.)