Several decades ago, possibly in a text written by Guyton or Bernstein, I
learned of this well-known physiological aphorism: "The body knows of
movement, not muscles" and I periodically have reincanted this in various
articles or seminars, but I have always entertained some reservations about
its validity in general.
Why should I have doubted its correctness? After all, it was emphasized by
world authorities such as the late great Russian scientist, Bernstein! Now I
no longer am willing to accept anything at face value, possibly because I
have become increasingly skeptical about many of the "facts" that are taught
in sports science and therapy.
There are a few reasons why we need to re-examine this saying:
1. Bodybuilders in their posing routines are able to "flex" various muscle
groups without moving any joint or limbs. They can "bounce" their pecs,
tense their quads and calves, select parts of the abs and tense them
alternately without any trunk action. In short, by focusing specifically on
certain muscles they eventually gain a large measure of control over certain
muscle groups without the need for any limb motion.
2. EMGs that have been taken of certain muscles have shown that the muscles
can tense in anticipation of any movement that is about to take place (as in
jumps from a height). In other words, the "virtual reality",
feedforwarding", "imagineering" or anticipation of movements or muscle
activation can stimulate muscle action before any movement takes place.
3. Biofeedback training, especially using EMG as an intervention, can teach
a person how to control specific muscle action without any movement taking
That is why in more recent times I have preferred to state that "the body
usually knows more about movement than muscles, but there are exceptions to
this general rule that may be important in motor control." So, before we
reflexively repeat that old saying, let us think very carefully about the
exact situation and context in which we believe it to apply, for we may be
neglecting some important exceptions to the "general rule."
Dr Mel C Siff