Not able-bodied volunteers may have long standing back or neck pain or pain symptoms as recently as several days after a date of injury. This more immediate window of pain will be allowed to include acute events but not until or unless the individual is able to perform the nine movements necessary for the MPR testing procedure. The outer time duration of pain was chosen to include individuals with more chronic complaints, but not if other compensatory or secondary gain issues appear present such as may occur with Worker’s Compensation claims, disability claims, or litigation. It is the desire of investigators to include appropriate acute, sub-acute, and chronic neck or back pain sufferers.