I found this article:
Now, although some individuals will try to tell you that increasing the sensitivity of motor neurons will enhance your "tone" by keeping muscles partially contracted even at rest; don’t be fooled; this isn’t possible.1234
Now, is he saying that you can't increase the sensitivity of motor neurons, or is he also saying that muscles are NOT kept partially contracted even at rest.. The first one I could believe, but the second one? I'm sitting upright now.. but I'm not thinking about keeping my neck muscles partially contracted so my head doesn't fall down..
Perhaps it is just that this resting muscle tone (motor neuron activity even at rest) is not something that is constant, but constantly changing in adaption to the needs. We have some reflexive loops, we all know of the typical short-loops like spinal stretch reflex (hit the knee cap with something and the leg will extend) but according to Rose & Christina (2006) there are "long-loop reflexive adjustments" these go further than just the spine, they reach "more distant subcortical and cortical levels of the CNS in order to connect with structures such as the motor cortex and cerebellum"
"the second type of long-loop reflex pathway is more involved in the regulation of more proximal muscles that subconsciously produce movements such as maintaining balance or performing gross body movements..."
Maybe this is what resting neural activity actually is.. not something that is constant, but something that changes depending on the need. For example in sports, you're still maintaining a good posture, but it probably requires more work than when you're just sitting still. So instead of calling it resting muscle tone, maybe one should just call it unconscious muscle control or something like that. But then again, this could be different from resting muscle tone. As I've always thought the nerves kept a constant small degree of activation in order to be able to act faster should an unexpected situation arise where you need immediate muscle action. Maybe I'll just have to wait until my next semester when I'm gonna take neurophysiology and ask someone there
Sorry for dragging this out, I really though we kinda reached a conclusion by post 19 and 20, but then I read that article..
but I think that article might be wrong, I've googled around and found a bunch of stuff referring to muscle tone as a degree of constant activation of the muscle. for example here:
