As mentioned in "A Different Paradigm", our vertical spines are routinely subjected to forces and postures that are essentially non-physiologic. The most common and ubiquitous is that of sitting--described medically as "Flexion Stress". There are also common spinal conditions that cause muscle group contracture or tightness that result in regional or segmental flexion, with some combination of side-bending or rotation.
Therapeutic Postures (TP) attempt to counteract distortions and restrictions of body movement by directly engaging tight muscle groups contributing to these restrictions. Many spinal conditions are degenerative in nature, have evolved over years to decades, and have become significant "pain generators". Pain of this nature generally causes a reflex muscle contracture, mediated by spinal cord nerve cells, that is sustained and involuntary. TP can address the muscle contracture component associated with many spinal conditions, but on account of the sustained nature of this dysfunction, deserve to be repeated many times a day to be effective.
TP can be effective in helping resolve "flare-ups" of spinal pain, such that medication and / or a trip to a doctor's office can be avoided. TP are safe, as they do not exceed physiologic barriers. They can be more specific if an examination has been performed, to better identify and classify what combinations of muscle group dysfunction are present.
Recommended TP may be altered as a condition is treated and progresses. However, given the frequency and sheer magnitude of hours most of us spend flexed (sitting), performing postures that result in some form of sustained extention--regularly--can be an effective way to prevent most spinal conditions from getting severe, or becoming chronic. This is one reason why people who practice some form of Yoga tend do not have back pain, or when they do, it is not as debilitating or limiting to them.
An osteopathic bio-mechanical exam can identify what segmental motion disturbances are present, and what treatment by the doctor (OMT) and by the patient (TP) will help to promote resolution.