Cervical spine manipulation (CSM) is utilized by many health care practitioners in the management of patients with neck pain and headache. How CSM works is not understood however, most researchers agree that there is likely a combination of mechanical, neurophysiological and placebo effects. This study will test for possible neurophysiological effects by examining for changes in a person's ability to reposition their head and neck in space, and maintain their balance following CSM.

Consenting participants will have their proprioception tested through a joint repositioning error test for their cervical spine, and also have their balance tested through a Neurocom Balancemaster. Following these pre-intervention measures, they will receive in a random order, either a cervical spine manipulation (CSM) or a sham manipulation, and then have tests repeated to analyze for changes and differences between interventions.

Inclusion Criteria:

• healthy individuals between the ages of 18 and 60

Exclusion Criteria:

• current neck pain/symptoms; neck pain symptoms within the last 6 months; confirmation or possibility of pregnancy; dizziness; vertigo, or nausea; history of cervical spine surgery; rheumatoid arthritis; osteoporosis; osteopenia; ankylosing spondylitis; cancer; or vertebral artery insufficiency.