We can extend the violin bow <=> air column analogy mentioned before for the sound laying during its initial emission : the first push of the bow sets the air column into vibration, at the very moment when inhaling becomes exhaling, during the handover from the diaphragm to the transverse abdominus muscle.
The division between the “upper“ and “lower“ parts of the body vanishes when it gets unified by the tilt of the pelvis.
To hasten the awareness of your back muscles and integrate them quicker into your instrumental action, it is recommended to “imagine“ them, to develop their role, to locate them, to play them at will (…)
One who knows how to terminate a sound is sure of being able to resume it.
Breathing (…) involves the entire trunk, from the nose to the anus, in a complex and admirable muscular synergy that appears as a huge wave which rises and falls down along the trunk, without border demarcation between the “upper“ and “lower“ parts of the body.
Inhaling then consists of an active tension of the diaphragm, together with a relaxation of the abdominal and pelvic muscles, while exhaling develops as an active tension of those same abdominal muscles pushing up the then-relaxed diaphragm.
Dominique Hoppenot, Le violon intérieur
(translated by Guy Robert)