A few weeks ago oboist Jennet Ingle wrote a post about the difference between the ways that string players and wind players rehearse. I thought that the comment I left today (somewhat edited here) responding to Jennet's question about teaching like a wind player might make an interesting post.
I always teach my string students about breath support, and how using the diaphragm can help with shifting and with saving bow. For students who have played wind instruments, I make analogies between the mechanics of the hand and arm and the mechanics of the air column and the tongue. I explain how the hand and fingers can be directly associated with the tongue, when you consider how we use our hands and arms when we talk, and when you consider how readily sign language becomes an instant vehicle of expression.
I suppose I will always think of phrasing like a wind player, unencumbered by the need to bow in either one direction or the other, but I also consciously take advantage of the fact that I can breathe during long notes when playing the violin or the viola. I believe that this extra-physical "power" is something that makes string playing compelling: string players can physically breathe in places that wind players and singers cannot. Heifetz used that kind of phrasing to great advantage.
String players often strive to phrase like wind players and singers. The idea makes a great deal of musical sense, but it is a physical impossibility, so string players have to create the illusion of phrasing like a singer. String players have to learn the physical sensation of having not enough air (in the case of the flute--in my experience), or too much air (in the case of the oboe and the recorder), and "translate" the experience into string-based actions. Running out of bow feels a little like running out of breath to me, but to someone who does not have the experience of being a wind player may not understand the sensation.
Wind players do not readily have the physical tools to make the kinds of contrasts in articulation and textures that string players can make, since all the mechanics for expression are on the inside, so wind players have to develop imagination. After years and years of having to rely on pure imagination in order to be able to have the colors and textures I wanted to have in my flute playing, that imagination still kicks in right away when I am teaching.
The pure string-playing approach to problems having to do with phrasing often takes visible physical elements into account first. Once those are under control (holding the instrument and the bow, the alignment and configuration of the left hand, the amount of bow being used and the location of that amount, the ease and comfort involved in getting from one note to the next), then we can concentrate on the relationships of notes within a phrase.
The wind-playing approach, as I see it, comes from creating a technique that is based on the relationship of the diaphragm to the throat and the tongue. When everything is in place, the diaphragm's role in taking in air opens the throat and lifts the soft palate. As long as the tongue remains in a forward position, there is air in the mouth. As long as the diaphragm remains strong and deep (without tensing the abdominal muscles), the air column will allow musical whims to happen, as long as the fingers remain efficient. Once the physical balance is set up you can spend a whole lesson on the musical aspects of the music at hand.
In my own string practice I find that I have to concentrate on the physical relationships of bow to string most of the time. If those physical relationships are working properly, then I can think about where phrases are going and how they relate to one another, but I find most often that I have to do something physical in order to make phrases come out the way I want them to. When practicing recorder (I don't have a working modern flute, so I don't practice that instrument) I find that once I am "set up" I don't need to do any physical "thinking" in order to have a phrase go where I want it to go.