The Alexander Technique teacher does some of the same things, that is, 
she observes with her eyes what movements you are making. But mainly she
 feels with her hands what you are doing. The process is not in fact so 
localized, but rather her hands act as the terminals of a neurological 
circuitry between your body and hers that helps her to recognize with 
her more finely tuned apparatus what is going on in yours. Different 
distributions of muscle tension give characteristic patterns of strain 
or ease. When muscle fibers contract, pulses of energy are given off. 
Relaxed muscle is quieter. Recognizing the best mix of quiet and noisy 
muscle in a body is the equivalent of recognizing from experience the 
optimum consistency for a cake mix, or the qualities that render a 
sonata more musical.
Using her hands to bring your attention to different parts of 
yourself, the teacher guides your musculature towards a new consistency.
 She uses some verbal instruction, but mostly she is showing you with 
her hands where you are holding where you shouldn’t be and where you are
 not holding where you should.
The tension mix is felt by the teacher’s whole body which in turn 
counteracts the wrong pulls with messages from her own better balance. 
Like many things that are evident in life nobody really knows quite how 
it works. But experience confirms that when the hands of a body that is 
opening out – or, in Alexander language, one that is “going up” – are 
placed on the muscular wrapping of someone who is shortening and 
narrowing, they stimulate it to release and open out. The experience can
 feel much like relaxing but without collapsing into a sagging shape. It
 would seem to be a sort of recognition response similar to the one that
 spreads smiles or yawns through a group.
A good pair of Alexander-trained hands gives you a feeling of load 
shedding. Lengthening and widening gives you an experience from where 
you can discover what you habitually do that pulls you down. You learn 
how to tune in to your body so you can collect more reliable information
 from your proprioceptive and kinaesthetic senses. The teacher’s aim in 
tuning in to her pupil’s body is the same as that of the tennis player 
who is acquiring the fine co-ordination that will hit the ball plumb in 
the middle of her racquet every time.
Continue reading : American Society for the Alexander Technique