Inclusion Criteria:

• History of ankle instability
• Ages 25-65 yoa

Exclusion Criteria:

• Recent surgery, have any unstable or fused joints of the cervical spine.
• Medications, prescription or herbal muscle stimulants, relaxants.
• Any previous cervical spine injury, surgery or condition affecting range of motion of the cervical spine.
• Any local infection, injury or other malignancy.
• Congenital conditions affecting the cervical spine, i.e. block vertebrae, Klippel feil syndrome.
• Any systemic illness that has an adverse effect on the cervical spine.
• A history of dizziness, light headedness or passing out.
• A history of neck or back injury.
• A history of serious automobile accident.
• Any spinal manipulation within 48 hours before testing or during the one week of testing.
• A score of less than 6 out 10 questions answered yes on the Functional Ankle Instability form (Appendix E) will disqualify the candidate for acceptance into the study.
• History of knee surgery and degenerative knee condition.