J Manipulative Physiol Ther. 1992 Jun; 15(5): 275-8.

Forces generated during spinal manipulative therapy of the cervical spine: a pilot study.

Kawchuk GN, Herzog W, Hasler EM.

Faculty of Physical Education, University of Calgary, Alberta, Canada.

OBJECTIVE: To determine the forces imparted to the cervical spine using direct sampling methods during a clinical episode of spinal manipulative therapy. DESIGN: Quantitative study. SETTING: Human Performance Laboratory, University of Calgary. PARTICIPANTS: Two doctor/patient pairs. Patients were selected by the treating chiropractors from their existing patients pools. INTERVENTIONS: SMT to the cervical spine (toggle method) on three separate occasions over a 2-wk period. The clinical relevancy of the treatment was assessed via before and after measures of tissue compliance. MAIN OUTCOME MEASURE: a) Forces during manipulation: preload and peak forces. b) Duration of applied forces. RESULTS: a) Mean peak force = 117.7 N (+/- 15.6 N). b) Mean duration of force = 101.7 msec (+/- 14.7 msec). CONCLUSION: The forces obtained with direct sampling methods compare favorably to previous measurements obtained from indirect sampling techniques, yet the force duration times are smaller (faster) using the direct method.