The purpose of this study was to investigate the relation between preload and peak forces during Spinal Manipulative Therapy (SMT). Forces during clinical trials of SMT were measured on the sacroiliac joint, the thoracic spine, and the cervical spine using a thin, flexible pressure pad (EMED Inc.). Preload forces were found to correlate well with peak forces during SMT, suggesting that the force required to move the joint of interest to the end range of passive motion (i.e., the preload force required) influences the magnitude of the treatment thrust. Furthermore, the change in force from preload to peak (∆F) also correlated well with peak thrusting forces for all SMTs tested, suggesting that the stiffness of the joint of interest at the limit of passive range of motion may be related to peak thrusting forces. Preload and corresponding (∆F) forces were not correlated highly.
Journal of the Neuromusculoskeletal System. 1993; 1(2): 52-8.
Author information: Herzog W, Kawchuk GN, Conway PJ. Human Performance Laboratory, Faculty of Physical Education, The University of Calgary, Calgary, Alberta, Canada.