Joint movement in the human body happens according to the principle of
antagonist contraction:
as the result of pairs of opposing muscles combining their tensions.
Rather than joint movement, could this combined tension
form a basis for the control of musical sound?
The answer is yes:
We can apply a force wave to the fingertip,
and then extract a scalar degree of freedom (DOF)
tracking finger tensing.
Moreover,
it is possible to then
implement tensing control
that occurs simultaneously with, but separately of,
fingertip control based on up/down movement.
This is
described here
(and, more precisely:
here, starting at p.137)
and
demonstrated in a video here.