Alexander technique is nothing but, securing the length and widths of neck, head, torso, legs,hands in sitting, stand ,bending, walking
OR
In any movement as a whole body use for the mindbody satisfactory movement.

1) the spine is not straight like a pencil.
2) the very edge back of the skull or head , the very edge of the thoratic spine, the very edge
of the sacrum spine are in one line.
3) the head compresses the cervical spine
the cervical spine compresses the thoratic spine
the thoratic spine compresses the lumbar spine
the lumbar spine compresses the sacrum spine
the sacrum spine compresses the pelvis,hip joints and to legs , to hands.
SO,
the head compresses the total body.
ALEXANDER TOLD CONCEPT AND IDEA IS PROVED.
4) if the head stays where it should be based on the design of the body no problem at all.
even one centimeter back and down of the skull or head may paradoxically disturb the freeness
of the total body.

one imortant point i noticed in you comment is:

WHEN THE SPINE IS POINTED, THEN THE SPINE IS IN LENGTHENED STATE.
WHEN THE SPINE IS NOT POINTED, THEN THE SPINE IS IN A COMPRESSED STATE.

when we bend consciously for picking the object on the ground making the spine compressed, we have a chance and choice of ,making the spine pointed after picking the object from the ground.

when the head forward and up back lenghten and widen , then the spine is already in pointed state.

when we keep one big straigh stick touching from back of the head to the sacrum, then
cervical spine, lumbar spine not touches to the stick. but
the back of the head,the thoraticspine, the sacrum spine touches the striaght stick.
IN THE ABOVE POSITION THE SPINE IS IN A POINTED DIRECTION.

i beleive the MEANSWHEREBY gives us the sensory and imaginative true lengths of the spine in the space.
the degree of the sensory awareness depends on the degree of the satisfactory physcophysical state of the body.
with out doing,and relating to the end and practicing the meanswhereby on a general basis, creates the satisfactory imaginative position of the humanorganisms or parts in the space .

thank you for your tip.