A high-velocity low-amplitude thrust (HVLAT) manipulation or commonly known as a spinal manipulation, is an intervention frequently used by physical therapists and other healthcare practitioners as an alternative treatment to help relieve spinal pain The mechanism by which HVLAT manipulation modulates pain remains undefined, although this does not contradict the clinical effects from HVLAT manipulation. Furthermore, there is evidence that suggests analgesia after HVLAT manipulation. There is a variety of observed and proposed phenomena that can explain the mechanisms for the psychological, mechanical, or neurophysiological responses from a HVLAT manipulation associated with alterations in pain processing or sympathetic and motor systems' excitation.