Controversial aspects of skeletal muscle tone.

It is being proposed that "muscle tone" comprises at least two mechanisms: a) reflex, neurogenic ("extrinsic") tone which is graded by reflex pathways and mediated by action potentials, and b) resting, myogenic ("intrinsic") tone which is not mediated by conducted action potentials, but is dependent upon local conditions in the muscle and is given by the number of sarcomeres and their mean length.