Movements of the Spinal Column

- 6 elementary lumbar movements:

Flexion
Extension
Right rotation
Left rotation
Right tilt
Left tilt

The last two are also called lateral pushups.

Shutterstock posterior: the spinal erectors. During this movement the nucleus pulposus of the intervertebral disc is pushed forward, stressing the anterior portion of the fibrous ring.

of the abdominal wall, but it is actually carried out by the spinal erectors which, gradually lengthening, counteract the force of gravity preventing the trunk from falling sharply forward.
During this movement the ligaments and the posterior muscles are stretched, the nucleus pulposus is pushed back causing a stress on the posterior portion of the fibrous ring, until it is fixed and broken with consequent migration of the nucleus.

and by some back muscles in synergy with the spinal erectors; the work of the latter will be all the more intense as the spine is bent forward, precisely because of their antigravity function.

The erector spinal muscles being involved in all movements of the spine undergo a shortening over time, with a consequent increase in pressure on the intervertebral discs.