Robin McKenzie (1931 – 2013) a physical therapist from New Zealand developed the Mechanical Diagnosis and Therapy system, called the McKenzie Method and it was published in 1981. He stressed that body bad habits of sitting affect the fluid nucleus to move posteriorly. As well as some repetitive movements and lifting may produce episodes of back pain. 

Back extension, as explained in details by McKenzie, reduces the stress on the posterior annular wall and simultaneously causes the fluid nucleus to move anteriorly. This is important in the treatment of back pain, according to McKenzie, who also explains how Centralization and Peripheralization are sings to know if the symptom of pain is getting better or worse, respectively.  He created a form of exercises and movements sequence to centralize back pain until a complete resolution of symptoms. 

In this case, an individual can determined immediately when the Pyraback™ is beneficial because the effects of centralization of pain. 

The Pyraback™ is also based on the physiology of a trigger point, as explained by Janet G. Travell, M.D and David G. Simons, M.D. in their 1992 book, “Myofascial Pain and Dysfunction: The Trigger Point Manual. Vol. II, (2nd ed. Baltimore: Lippincott Williams and Wilkins). A trigger point knowing as a contraction of a small part of the fiber is defined as a “Highly irritable localized spot of exquisite tenderness in a nodule in a palpable taut band of muscle tissue”. A trigger point feels like a knot or a small lump that can range in size from a pinhead to a pea (see it as red dots in the sarcomeres drawings). In the long muscles, a trigger point feels like a short piece of cord and can easily be mistaken for a tendon.