Force-Time Characteristics of Posterior-to-Anterior Thoracic Spinal Manipulations under Simultaneous Longitudinal Axial Distraction of the Spine

M.R. Gudavalli and J.M. Cox (USA)


Spine, Thoracic, Forces, Chiropractic, Low velocity, Spinal Manipulation


The objective of this paper was to collect force-time data while delivering posterior-to-anterior thoracic spinal manipulations. A portable system consisting of three dimensional force transducers, laptop computer, and custom developed software was used for this study. The system was used to quantify the forces during PA spinal manipulations delivered at low velocities while the spine is simultaneously subjected to longitudinal axial traction. A total of five patients were treated by an experienced clinician and delivered cross bilateral spinal manipulations to the thoracic spine. The forces applied in the posterior-to-anterior direction, and the duration of the cycle time, rates of loading and unloading, and the forces in the other directions, as well as the forces under the both hand contacts of the doctor-patient were analyzed. The thrusting hand average forces in the PA direction were 169N and the stabilizing hand forces were 106N. The inferior-to-superior forces were 30N, and the lateral forces were 3N. Average manipulation cycle time was 2.54sec, average rate of loading was 147N/sec. Compared to high velocity low amplitude spinal manipulations, the forces were smaller and the duration of the manipulation is larger and the rates of loading are smaller. This is the first study to report on the force-time characteristics of a PA low velocity manipulation delivered under simultaneous longitudinal spinal traction.

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