A recent article reports a synthesis of literature concerning PAIVMs & stiffness, including the results of different modelling studies as well as in vivo measurements.

Spinal PA movements behave ‘as if’ there are limitations of local segmental mobility and are large enough to be perceivable by manual palpation: A synthesis of the literature, Tuttle N, Musculoskeletal Science and Practice, 2018.

Have a look: https://doi.org/10.1016/j.msksp.2018.04.005

Véronique