it's a practice of undoing all of the negative habits we have learned. largely intriguing how the body is connected to itself, with one element affecting another.
for example one thing that i learned was that if, while playing, i made a large move up the fretboard (toward the bridge) with my left hand moving from a major shape to a minor shape (regardless of if i was using those tonalities or not), than my left fore arm would tighten, my left shoulder would tighten, my neck would tighten up, and my lower back would lose it's posture. my head would also drop and my breathing would be restricted. thus being aware of this i slowed my practice down and have now come to terms with the motion and, at least, i now am a bit more relaxed with the motion and still breath while making the leap. quite fascinating.
here's some information on it. i highly recommend reading about Mr. Alexander as well and talking to someone about it.
http://www.alexandertechnique.com/mu...o%20Guitarists http://www.alexandertechnique.com