Jack Laumer used to always talk to me about how string players produced sound using the bow. Pretty much on every aspect of playing, I try to imagine how they would use the bow on different articulations, volumes, and timbres - the length of the bow string being the amount of air used, the length of actual bow used in one motion being the volume, and the combination of both creating different timbres. A very natural motion for a first attack on violin is to raise the bow up (off the string) and then down onto the string in one fluid motion. If the violinist were to raise (inhale), pause, then lower (exhale), the attack would be unclear, lack good tone, and most importantly - be out of time. Our bodies love to be in rhythmic sync within it's own body parts. Efficient playing starts when the exhalation, lip tension, tongue, and fingers are in the exact same place and time. That's why it's important to breathe in some sort of tempo and release without pause. This windup prepares the body to be in sync just as a golf swing, football throw, or pool cue strike would need to be successful. None of those physical motions contain a pause.