Impact of Practitioner and Instructional Set on Subject Perceptions and Expectations of Cervical Spine Manipulation

Inclusion Criteria: 1. age 18-65 years; 2. must report having no current episode of mechanical neck pain; 3. must be willing to participate; 4. must indicate they have not had their neck manipulated by a physical therapist, osteopath or chiropractor within the last 5 years. Exclusion Criteria: 1. 'Red flag' items indicated in your Neck Medical Screening Questionnaire such as: history of a tumor, bone fracture, metabolic diseases, rheumatoid arthritis, osteoporosis, severe atherosclerosis, prolonged history of steroid use, heart disease, and stroke. 2. History of neck whiplash injury. 3. Diagnosis from your physician of cervical spinal stenosis (narrowing of spinal canal) or presence of symptoms (pain, pins and needles, numbness) in both arms. 4. Presence of central nervous system involvement such as exaggerated reflexes, changes in sensation in the hands or face, muscle wasting in the hands, altered taste, and presence of abnormal reflexes. 5. Evidence of neurological signs suggesting nerve root entrapment (pinched nerve in the neck). 6. Prior surgery to your neck or upper back. 7. A medical condition which may change your sensation of pain or pressure pain thresholds (i.e. taking analgesics, sedatives, history of substance abuse, or cognitive deficiency). 8. Diagnosis from your physician of fibromyalgia syndrome. 9. Currently pregnant, or think you may be pregnant.