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

Which is worse  lifting and twisting or twisting alone ? Or was the 10960’s dance, the twist, actually safe as long as you didn’t lean forward

This study investigated the role of “repeated dynamic axial torque/twist combined with repeated flexion on the disc herniation mechanism”

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