Subject: The Activator® Adjusting Instrument – Biomechanical

Title: Biomechanical Characterization (fingerprinting) of Five Novel Methods of Cervical Spine Manipulation

Reference: Kawchuk GN, Herzog W. Biomechanical characterization (fingerprinting) of five novel methods of cervical spine manipulation. J Manipulative Physiol Ther 1993; 16(9):573-7.

Abstract:
Objective: To determine the biomechanical characteristics of five clinically common methods of cervical spine manipulation. Design: Descriptive study.

Setting: Human Performance Lab, University of Calgary.

Participants: Five volunteer practitioners treating symptomatic patients from their own clinical populations.

Intervention: Five commonly used methods of cervical spine manipulation: lateral break (LAT), Gonstead (GON), Activator (ACT), toggle (TOG), rotation (ROT).
Main Outcome Measure: Mean thrust duration (msec), normalized mean peak force (N), slope (N/msec), normalized mean peak force (N), slope (N/msec), force profile (graphic representation of the above values).

Results: Outcome measures for each manipulative technique were as follows: LAT = normalized mean peak force of 102.2 N at 86.7 msec. GON = 109.8 N at 91.9 msec, ACT = 40.9 N at 31.8 msec, TOG = 117.6 N at 47.5 msec, ROT = 40.5 N at 79.1 msec.

Conclusions: The observed differences and similarities in force profiles between the five techniques studied here may partly be the manifestation of how a particular technique delivers force to the cervical spine. The clinical significance of force profile characterization is not yet known. (J Manipulative Physiol Ther 1993; 16:573-577).


Key Words: Biomechanics, Force, Cervical Vertebrae, Manipulation, Chiropractic