What does an adjustment do?

Adjustment is the conglomerate term Chiropractors use to describe a set of modalities (treatment tools).  They vary enormously from so called 'low-force' techniques to the traditional HVLA adjustment (High Velocity Low Amplitude (short distance)).  In the hands of a clinician who is trained and experienced at knowing not just what but when and how to apply it these approaches can be very effective for various neuromusculoskeletal disorders.

Sometimes people will ask "what does it do".

Here's a list of some effects which have been observed during neuroscience research (courtesy of Matthew Long CDI)

• Engages mechanoreceptors to open mechanically gated ion channels and initiate a current flow into the largest and fastest primary afferent neurons.
• Uses a rapid lengthening of muscle to activate the dynamic components of the muscle spindle receptor to fire 1A afferents at a high frequency in order to modulate central neurology (greater than 200 Hz).  
• Alters the gain on the muscle spindle system to change muscle tone via the action of gamma motor neurons that innervate the intrafusal muscle fibres.
• Produces a ‘novel’ blend of sensory input that alters the state of the dorsal horn and shapes the responsiveness of spinal cord neurons to future inputs.
• Induces plastic changes in neural circuits via long-term potentiation and depression, depending upon the type of circuit i.e. manipulation can produce long-term depression of the projection neurons of the pain pathways.
• Alters the genetic responses in spinal cord neurons and those in the higher centres.
• Produces a propagated response in neurons in the ipsilateral cerebellum.
• Alters the frequency of firing of lower motor neurons to produce a change in muscle tone, joint stability, position and motion.

Doug Scown