Effects of Foot Orthotics on Dynamic Postural Control Tasks in Subjects With Chronic Ankle Instability

The purpose of this study is to determine the effects of orthotics on dynamic balance tasks in subjects with chronic ankle instability. The dynamic balance tasks will be a single limb task called thc Star Excursion Balance Test (SEBT) and a double limb stance on the NeuroCom SMART Balance Master callcd the Limits of Stability (LOS). Twenty subjects with selfrcported chronic ankle instability (CAr) will participate in this study and complete three test occasions (I familiarization session and two test sessions). Our hypothesis is that the use offoot orthotics will improvc reach distances in subjects with CAr during the SEBT and that directional control and endpoint excursion will be improved in CAr subjects during the LOS test. All subjects will complete a health history questionnaire as well as a CAr questionnaire. Each testing session will consist; of a 5 minute warm-up on a stationary bike stretching exercises, 6 practice trials of the SEBT, 3 test trials ofthe SEBT, 2 practice trials of the LOS, and 2 test trials of the LOS. Subjects will bc fitted for neutral scmi-rigid orthotics on the first testing session. On subsequent test sessions subjects will perform each tcst with and without orthotics and the order will be counterbalanced. This study is a multiple test occasion repeated measures design. The independent variables are Condition (orthotics, or no orthotic) and Time (Week I and Week 4). The dependent variables are reach distance in the SEBT, and endpoint excursion and directional control in the LOS tcst. Three 2 x 2 repcated measure ANOV A's will be performed for the SEBT and LOS. The expected outcomes include: I) Increased reach distances in all directions of the SEBT with the use of orthotics, 2) A decreasc in side to side SEBT reach differcnces within subjects with the use of orthotics, 3) An increase in the perccntage of dircctional control in the LOS with the usc of orthotics, and 4) An increase in the percentage of endpoint excursion of the center of gravity in the LOS with the use of orthotics.