This seems simple enough but up, as used in the Alexander Technique, is not necessarily up towards the sky. ‘Up’ is always referring to a lengthening flow through our bodies, up along our spine, whatever direction the spine is assuming at the time. So if you are lying down, up is actually a horizontal lengthening.
Importantly, it is a refusing to pull down and contract or shorten the neck, spine and torso, which would interfere with our primary control and general functioning.
As Alexander researched the causes of his vocal problems he found that
'the best conditions of my larynx and vocal mechanisms and the least tendency to hoarseness were associated with a lengthening of the stature'... and that 'it was necessary that my head should tend to go upwards, not downwards, when putting it forward; in short, that to lengthen I must put my head forward and up'.