Further, if the excursion could be preset or remotely controlled without the knowledge of the DC, blinding of the doctor could be achieved as well. This instrument is a prototype which delivers an electronically controlled thrust and which senses the positional, force and velocity parameters of the adjusting stylus and makes them available to a computer for monitoring, storage, analysis and display. With this device, it is possible to study a wide variety of questions about precision adjusting and material properties. We therefore chose to study whether changes in the adjustive thrust are important to outcome. Preload is defined as the static force between the stylus and the tissue of the neck prior to delivery of the thrust.
Excursion is defined as the distance the stylus moves during the thrust.
Generally, the greater the preload and excursion, the more force encountered by the stylus. This work hypothesizes that the greater the preload and excursion, the more effective would be the adjustment. Participation was contingent upon passage of the clinic physical and signing an informed consent. Except for controls, subjects were blinded to their group assignments but were aware that group differences existed. Note that in the Zero preload groups, the stylus is moved back far enough so that it never contacts the skin.