Our purpose is to examine the combined effects of thrust mobilization of the ankle joints in conjunction with a six-week rehabilitation program on functional performance in subjects reporting chronic ankle instability (CAI).

Joint mobilizations are reported to increase range of motion (ROM), postural control and proprioception, and decrease pain in individuals with CAI. However, there is no research supporting the combined effects of thrust mobilization and exercise on function in this population.

Inclusion and exclusion criterion have been established utilizing the International Ankle Consortium guidelines. Using a convenience sampling, participants will be randomized into the exercise only or mobilization (experimental) and exercise group. Both groups will undergo 12 supervised training sessions across a six-week period. The mobilization (experimental) group will also receive high-velocity-low-amplitude (HVLA) thrust mobilizations at the talocrural, proximal, and distal tibiofibular joints prior to the first three treatment sessions.

An examiner, who is blinded to involved limb and group allocation, will perform a baseline and six-week follow-up examination of joint mobility, range of motion, and functional performance. The participants will complete subjective outcome measures at baseline, 2 weeks, 4 weeks, and 6 weeks including the Foot and Ankle Ability Measurement (FAAM), FAAM-Sport, Ankle Joint Functional Assessment Tool (AJFAT), and the Cumberland Ankle Instability Tool (CAIT). Participants will also complete baseline and six-week follow up assessments of the figure-of-8 hop test, side hop test, and three directions of the Star Excursion Balance test (SEBT).

The exercise protocol is a modified version of the balance training program described by McKeon et al. Participants will complete this protocol twice a week for six weeks. Treatment sessions will last approximately 30 minutes. Participants will individually progress on particular exercises if zero errors are observed. In addition, all participants will be given a home exercise program (HEP) to complete every day of the week excluding treatment days.

The mobilization (experimental) group will receive HVLA thrust mobilizations at the three joints stated above for the first three sessions prior to completing the exercise protocol. Each mobilization will be performed one time at each joint. The order of joint mobilizations will be randomized prior to administering.

Data analysis will be performed using International Business Machines Statistical Package for the Social Sciences (SPSS). Alpha level will be set p<0.05. Expecting to utilize separate 2 x 2 repeated measures analysis of variance (ANOVA) to assess changes in the FAAM, FAAM-Sport, AJFAT, CAIT, figure-of-8 hop test, side hop test, and three directions of the SEBT.

As adapted from the position statement from the international ankle consortium.

Inclusion Criteria:

• 18-35 years of age
• A history of at least 1 significant ankle sprain (The initial sprain must have occurred at least 12 months prior to study enrollment, associated with inflammatory symptoms (pain, swelling, etc), created at least 1 interrupted day of desired physical activity)
• The most recent injury must have occurred more than 3 months prior to study enrollment.
• A history of the previously injured ankle joint "giving way" and/or recurrent sprain and/or "feelings of instability."
• Cumberland Ankle Instability Tool (CAIT) < 24
• Foot and Ankle Ability Measure (FAAM)42: ADL scale < 90%, Sport scale < 80%

Exclusion Criteria:

• A history of previous surgeries to the musculoskeletal structures (ie, bones, joint structures, nerves) in either limb of the lower extremity.
• A history of a fracture in either limb of the lower extremity requiring realignment
• Acute injury to musculoskeletal structures of other joints of the lower extremity in the previous 3 months, which impacted joint integrity and function (ie, sprains, fractures) resulting in at least 1 interrupted day of desired physical activity