The aware practicing of your central nervous system fosters proprioceptive images, which facilitate the flow of your inner vibrating sound towards your instrument. This vibration is directly fed by your quiet natural breathing, and may be visualized as being softly laid on your deep sound source.
Then, your sensation of being seated on the sound actually links your brain to your musical speech, making you forget about your body (the expression tool) and your instrument (the vibration amplifier).
Practicing at the piano is mainly practicing of the central nervous system, whether we are aware of it or not.
Du Bois-Reymond said that motor activity of the human body depends upon the proper interaction of muscles more than upon the force of their contraction.
[Steinhausen on the psychic origin of technique : in 1905, several months after the appearance of Rudolf Maria Breithaupt‘s Die Natürliche Klaviertechnik, Dr. Friedrich Adolph Steinhausen’s Die Physiologische Fehler und Umgestaltung der Klaviertechnik (“The Physiological Misconceptions and Reorganization of Piano Technique“) was published.]
Since every movement is initiated in the central nervous system, practicing is, first and foremost, a psychic process, the working over of accumulated bodily experiences and the adjustment to a definite purpose.
(…) Through practice we can learn to move our fingers at the right time and in exact succession in accordance with a given musical figure. We can also achieve the ability to make fine gradations of tonal volume. But this learning is mental and has nothing in common with the degree of muscle development.
“A quantitatively small alteration in the brain has much greater importance than the most significant muscle enlargement.“
(…) Technique is the interdependence of our playing apparatus with our will and our artistic intentions.
Repeated application of the unconditional stimulus (movements of the playing apparatus) diminishes the extent of irradiation and helps to concentrate excitation. This will then affect only the concerned cells of the cortex’s motor region. For best results this application should be carefully controlled : movements must be watched and unnecessary muscle contractions must be avoided.
George Kochevitsky, The Art Of Piano Playing