https://www.researchgate.net/publication/377361433_A_randomized_controlled_trial_comparing_different_sites_of_high-velocity_low_amplitude_thrust_on_sensorimotor_integration_parameters

Over the last 30 years of practice I have often found myself answering the same question many times over. 1 of those questions is why I seem to only be adjusting only one side and only one very specific spot, when patients may have had previous experiences with chiropractors or other manual therapist that showed a much broader contact, and adjusting multiple areas of the spine on both sides. With the addition of Dr. Steve as my esteemed colleague and associate, I realize I'm not the only one answering that question. Dr. Steve and I have very similar approaches and background in manual adjusting, (more specifically we both had most of our training in the Gonstead technique and system), which means that on occasion we will both bemoan the drift of our profession away from specific and systematic manual adjustments based on a system of analysis that aims at isolating the main segment(s) of spinal dysfunction that should be adjusted, while leaving the rest alone.

There are good scientific rationales behind that approach: the spine is a very dynamic system of action and reaction based in gravity. What happens in one area of the spine will often lead to broad compensations in a different area, and it takes some clinical investigation to make sure you address the root cause rather than waste your time (and your body's limited healing energy) on areas of compensation.

There is also good and pretty solid research to validate the specific approach. I was thrilled to come across this wonderful paper by our colleagues from down under in New Zealand (especially Dr. Heidi Haavik who has been a workhorse of basic science chiropractic research for well over a decade). The nuts and bolts of the study was to measure the brain-based motor response of an adjustment in a randomly selected area of the spine across the test subjects, versus a specific spinal segment determined by chiropractic analysis including static palpation, palpatory tenderness, abnormal motion segment etc.). The results were statistically incredibly different between the 2 interventions.

The moral of the story is that chiropractic care is most likely to give you longer-lasting neurologically integrated results if your provider spends time to specifically isolating the main problem area and adjusting it according to best biomechanical correction principles.