In which of the following fields is the 'Alexander Technique' considered extremely relevant?

The 'Alexander Technique', named after its creator Frederick Matthias Alexander, is an educational process that was created to retrain habitual patterns of movement and posture. Alexander believed that poor habits in posture and movement damaged spatial self-awareness as well as health, and that movement efficiency and improved carriage could support overall physical functioning and well-being.

Alexander began developing his technique's principles in the 1890s in an attempt to address voice loss during public speaking.

Frederick Matthias Alexander (1869–1955) was a Shakespearean orator from Tasmania, who developed voice loss during his unamplified performances. After doctors found no physical cause, Alexander reasoned that he was inadvertently damaging himself while speaking. He observed himself in multiple mirrors and saw that he was contracting his posture in preparation for any speech. He hypothesized that a habitual conditioned pattern (of pulling his head backwards and downwards) needlessly was disrupting the normal working of his total postural, breathing, and vocal processes.

With experimentation, Alexander developed the ability to stop the unnecessary and habitual contracting in his neck, displacement of his head, and shortening of his stature. As he became practised at speaking without these interferences, he found that his problem with recurrent voice loss was resolved.