Singing is all about movement which creates sound and silence. Music is all about this sound and silence.
We make good music as singers when we learn how to allow the vocal muscles and the air to move, and even to stop moving in a healthy and rhythmic manner so as to not violate the laws of nature.
The vocal muscles move; achieving a balanced equilibrium is the healthy goal. The air moves. We breathe in and out without attempting to hold or “control” the flow. The muscles and air move together in balance as well, neither dominating the other.
Over-muscularity stops the steady flow of air, and blowing too much air upsets the balance between the muscles.
So, we breathe in and sing out. If the muscles are responding well, then they will find balance given what is musically needed and respond with free vibration.