Immediate Effects of Manipulation Versus Stretching on Upper Trapezius Pressure Pain Thresholds

Inclusion Criteria: 1. Absence of current neck pain 2. Aged 18 - 70 years 3. Able to lie on stomach or back without difficulty Exclusion Criteria: 1. 'Red flag' items indicated in Neck Medical Screening Questionnaire such as history of a tumor, bone fracture, metabolic diseases, Rheumatoid Arthritis, osteoporosis, severe atherosclerosis, prolonged history of steroid use, etc. 2. History of neck whiplash injury 3. Diagnosis from physician of cervical spinal stenosis (narrowing of spinal canal) or presence of symptoms (pain, pins and needles, numbness) down both arms 4. Presence of central nervous system involvement such as exaggerated reflexes, changes in sensation in the hands, muscle wasting in the hands, impaired sensation of the face, altered taste, and presence of abnormal reflexes 5. Evidence of neurological signs consistent with nerve root entrapment (pinched nerve in the neck) 6. Prior surgery to neck or upper back 7. A medical condition which may influence assessment of pain or pressure pain thresholds (i.e. taking analgesics, sedatives, history of substance abuse, or cognitive deficiency) 8. Diagnosis from physician of fibromyalgia syndrome 9. Currently pregnant, or could be pregnant