"What I have been describing is how to gain control over muscles that we are not even aware of. Clearly, any movement using stabilisers must seem powered by something else than muscles. In Chinese culture, qi is a cause of movement so it is not surprising that the kind of movement I've been describing would be attributed to qi. We have seen how this ‘qi' is trained by the mind (awareness) and activated by the mind. Sometimes ‘bone breathing' or ‘bone squeezing' methods are used to ‘congeal qi into bones'. This is just another way of gaining awareness of the deep muscular structures. Awareness of the stabilisers is felt like a tightness round the bones. Due to the structure of slow-twitch fibres, deliberate use of stabilisers produces more heat than is usual. This can be felt and it is different from a similar, but smaller, effect in the skin brought about by relaxation. Both of these effects, but especially the heat produced deeper in the body, are often taken as a sign of increased ‘qi' flow."
All very good. The main problem is that the control sought must necessarily be done by indirect means to learn what alters them.
What does alter them? A simply demonstrated one is repetitive stress. If you have had your hands that won't easily unclench after a good quarter hour or so of heavy raking, or after handling a rotary hammer or after pushing a particularly rough running lawn mower, you know exactly what I mean. [[@ Joep -- Those are the "stabilizers" David is talking about ( there are more complicated names, but that is the right functional description.]] Similarly, if you have had to shift awkward loads (like say bags of cement), the first couple seem very ungainly, but after two or three you have immensely better stability and can project them further, and you didn't consciously DO anything differently. Same action is occurring but in the larger and more central postural elements.
Now in traditional Aiki training we have interesting exercises in this light: furitama "spirit shaking", tekubi-furi "wrist shaking," and funetori "boat rowing" The first two are cognate to the vibrating machinery and the latter to tossing cement. We also beat on our bodies from thighs to finger tips to feel the impulses running through out the body. Done correctly, in all of them you sense resonance in the body and its various scales of movement, moving larger components with a small resonant rhythm, and conversely driving small components with a larger cycling mass.
All of these are directed at teaching the immensely quick spinal reflexes and the cerebellum and its more complex reflexes to modulate these responses in more "clever monkey" ways -- but importantly, in BOTH provoking AND in suppressing that response in variations and at need. An important caveat is that these tissues are hormonally provoked as much or more than they are by the sympathetic nervous system (which itself provokes the adrenal system if sufficiently activated. But these tissues are not responsive to adrenal homromones -- they are responsive to oxytocin (the "love" hormone) -- which suggests a strong empirical support for a certain attitudinal approach to training.
In provoking that response you are modulating the damping function of the structure to absorb and dissipate cyclic loads, and in suppressing it you are opening the body to transmit, more transparently, the same type of cyclic energy transiting the body. "Clear power" Sagawa called it, appropriately enough.
In dynamic form, angular momentum can transmit and concentrate for delivery tremendous kinetic loads in the human body. In static form the same "shape" and elements are adopted but in a "snapshot" as though the motion was caught in a video frame that provokes the stabilizing action but progressively to dampen (like pure alcohol suddenly and progressively turning to stiff molasses) the applied momentum -- ultimately using the summmed dampening potential of every connection in the whole structure to "eat up" the load. Otherwise "odd" aspects of aikido training like the tegatana arm form and the directly related forms and principles of asagao are fully comprehensible when you understand this perspective.