Disc

“Damage to the annulus of the disc (herniation) appears to be associated with fully flexing the spine for repeated or prolonged period of time. In fact, herniation of the disc seems almost impossible without full flexion. This has implications for exercise prescription particularly for flexion stretching and sit-ups or for activities such as prolonged sitting, all of which are characterized by a flexed spine. Some resistance exercise machines that take the spine to full flexion repeatedly must be reconsidered for those interested in sparing the post annulus portions of their discs. Furthermore the mechanism by wich the process can be interrupted appears to be postural dependant, providing more insight into the mechanism of the Mckenzie approach.”
McGill, Stuart. Low Back Dissorders Eidence-based Prevention and Rehabilitation. 2. Champaign,IL: Human Kinetics, 2007.47

“Clearly Herniations are a function of repeated full-flexion motion

cycles.”
McGill, Stuart. Low Back Dissorders Eidence-based Prevention and Rehabilitation. 2. Champaign,IL: Human Kinetics, 2007.46

“We have found that the herniation process begins from failure in the innermost annulus rings and progresses radially outward. The layers of the annulus delaminate and fill with nucleus material . We now have proof that the extended posture can drive the nucleus material that is in the delaminated pockets of the posterior nucleus back tward the central part of the disc.”
Scannell, J., and McGill,S.M.(2005) Spinal Disc Prolapse caused by flexion can be reduced by extension: an into study of disc mechanics. Canadian Biomaterials Society, Waterloo: May 26-28.

“It would appear that the disc must be bent to the full end range of motion in order to herniated.”
Adams ,M.A., and Hutton,W.C. Prolapsed intervertebral discs: A hyperflexion injury Spine,7:184

“Disc herniation is associated not only with extreme deviated posture, either fully flexed or bent, but also with repeated loading in the neighborhood of thousands of times, highlighting the role of fatigue as a mechanism of injury.”
Gordon,S.J., et al.(1991)Mechanism of Disc Rupture- a preliminary report. Spine 16:450

“Epidemiological data link herniation with sedentary occupations and the sitting posture.”
Videman, T.,Nurminen,M., and Troup, J.D.G.(1990) Lumbar spinal pathology in cadaveric Material in relation to history of back pain, occupation and physical loading. Spine,15(8):728