Forces measured during spinal manipulative procedures in two age groups.

Objective. Manipulation techniques have a prominent, yet controversial, role in the treatment of back pain. Their use varies widely between the professional groups and between individual therapists, with no accurate method of standardizing or quantifying the treatment administered. Methods. An instrumented mobilization couch was developed to measure and characterize typical forces used during spinal manipulative therapy. The couch was used to measure the forces applied to the lumbar spine of 30 young healthy subjects during five mobilization techniques, and to a clinical sample of 31 patients, aged between 45 and 65 yr. Results. The magnitudes of the mobilization forces were found to be similar for the young and the older groups. Median forces of 164 and 168 N, respectively, were recorded during a Grade III procedure. However, the forces applied to the older group exhibited a smaller amplitude and higher frequency of oscillation than those applied to the young group (P< 0.001). Conclusion. Objective measurements can be used to characterize manipulative forces for both evaluative and teaching purposes.