The British Medical Journal published (Aug 2008 - see link below) published a proper clinical trial of the effect of Alexander lessons on back pain.
It concluded that lessons in the Alexander Technique were both effective and cost effective.
Alexander lessons aim to deal with the possible underlying causes of the symptoms of back pain - to re-educate the wrong uses of our muscles to which we have become habituated. Improvement in our habits will have the effect of a general improvement in our balance as a whole. Symptoms of back pain are alleviated or they disappear because the general conditions, of which the back pain was a symptom, are improved.
This means that pupils should gain other benefits besides relief from their back pain.
Read more here:
>>Randomised controlled trial of Alexander technique lessons, exercise, and massage (ATEAM) for chronic and recurrent back pain.