Lumbar manipulations or adjustments (like I am performing in this video) involve specific positioning of the patient’s body and a specific movement (direction, magnitude of force and amplitude) by the practitioner that often leads to a cavitation or ‘pop’ of the underlying joints.
What you should know is that the popping sound you hear when having a joint manipulated is nothing more than a pressure change within the joint capsule. It has nothing to do with correcting the alignment of the bones.
The pain reduction that comes from these techniques is thought to be neurophysiological in nature and related to changes in nociceptive processing within both the peripheral and central nervous system divisions. Placebo is also a major contributor to any reductions in pain that are seen with manipulation.
At the end of the day, research has demonstrated time and time again that manual therapy can be helpful, but the effects are largely short-lived. A long-term recovery program should focus more on active interventions (movement & exercise) as these have stronger evidence in terms of promoting more permanent changes in both function and pain.
Reference: Gyer, et al. Spinal manipulation therapy: Is it all about the brain? A current review of the neurophysiological effects of manipulation. J Integr Med. 2019.