Does hyperextension have an unloading effect on the intervertebral disc?

A stadiometer (a device to measure the overall height of a subject) was used to determine the effect of hyperextension in rehydration of the intervertebral disc. Hyperextension for 20 minutes in a prone posture was compared with the prone posture alone for 20 minutes. The stadiometer measurement was made after the subject was exposed to 10 kg of loading applied to the shoulders for five minutes and after each of the recovery postures. It was found that hyperextension gave a significantly increased height recovery compared with the prone posture.