So many of us suffer from poor posture, which is one of the most prominent physical challenges that my students face while learning how to use their singing instruments. Posture affects everything (Breathing, tone production, range, flexibility, you name it), so I spend a great deal of time working with each individual student on finding their body's most natural alignment. This often involves customized stretches, acupressure work, massage work, and strengthening exercises, which I try to incorporate into lessons as much as possible.
If we think of our bodies like the tube of a flute, having poor posture would be like bending the flute in several different places, and expecting it to sound pretty, and play easily. The more lined up our bodies are, the more our muscles can relax, and the more open our instruments will sound. Bad posture also results in massive amounts of asymmetrical tension in the body, which will be discussed in more detail in another post.
If you suspect that you might have poor posture, have someone take a few pictures of you from the side. Notice if the head wants to be in front of the shoulders, or if the shoulders want to roll forward, and if the chest wants to cave in. Notice the position of the hips - are they underneath you, or are they in front/behind you? Notice your lower back - is it crunched up, or is it long and open? These are all things that I go through with each of my students, so we can design a bodywork regimen that is suited to each unique instrument.