The Alexander technique (AT) teaches people how to stop using unnecessary levels of muscular and mental tension during their everyday activities. It is an educational process rather than a relaxation technique or form of exercise. The Alexander technique has been shown to help with back pain, which is often caused by repeated mis-use of the body over a long period of time. The purpose of the Alexander technique is to help people shed/unlearn bad physical habits and return to a balanced state of rest and poise in which the body is well-aligned.
The technique is named after actor Frederick Matthias Alexander, who developed its principles in the 1890s as a personal tool to alleviate breathing problems and hoarseness during public speaking.
As for me, the emphasis in an AT lesson is on relationships: between the different parts of the body, between the body and its surroundings, and between the mind and the body.
In order to bring a change in the body, we first learn to pause between a stimulus that elicits a movement and the habit-based response. We then modify the thought process, the intention to move, and finally allow the new intention to be embodied. The AT provides tools for changing habits, for changing from a body that is held and constricted to an expanding, freer entity.