Marshall LW and McGill SM. (2010) The role of axial torque in disc herniation. Clinical Biomechanics, 25(1):6-9. you can review an abstract here
1) Axial torque/twist in combination with repetitive flexion extension motion, regardless of order, encouraged radial delamination within the annulus .
2) Alternatively, repetitive flexion motion alone encouraged posterior or posterolateral nucleus tracking through the annulus.
3) Axial torque/twist alone was unable to initiate a disc herniation.
4) X-ray images with (contrast and computed tomography) are not good at detecting radial delamination
The problem this paper gives me is whether or not “twisting exercises” ( without flexion) should be removed from back exercises . It concludes afterall that “Axial torque/twist alone was unable to initiate a disc herniation”. Ill try and find out