Functional Performance Testing in Participants with Functional Ankle Instability and in a Healthy Control Group

Context: Functional ankle instability (FAI) affects a large part of the population. Inconsistent findings have been reported regarding the existence of functional performance deficits in individuals with FAI.

Objective: To examine functional performance in participants with FAI compared with participants in a control group during 2 hopping tests.

Design: Case-control study.

Settings: Athletic training research laboratory.

Patients Or Other Participants: There were 40 college-aged individuals who participated in our study: 20 with FAI and 20 without FAI. We defined FAI as history of an ankle sprain and residual episodes of "giving way."

Intervention(s): Participants completed 2 functional performance tests (FPTs): the single-limb hopping and the single-limb hurdle tests.

Main Outcome Measure(s): Time to complete each test was recorded. Following each FPT, participants were asked if their ankles felt unstable during the test.

Results: We found no difference between participants in the FAI and control groups for the hopping or hurdle tests (P > .05). When asked if their ankles felt unstable during the FPTs, approximately half of the participants in the FAI group and none of the participants in the control group reported a feeling of instability. Subsequently, a secondary analysis of variance was calculated with participants grouped into 3 categories: control participants, FAI participants reporting instability symptoms during FPT (FAI-S), and FAI participants not reporting instability symptoms during FPT (FAI-NS). Results revealed a difference among the 3 groups for the single-limb hopping test (P < .01). Post hoc analysis revealed a difference between the FAI-S participants and both the control and the FAI-NS participants. No difference was identified for the single-limb hurdle test (P = .41).

Conclusions: The FAI-S participants had performance deficits during the single-limb hopping test. Therefore, clinicians could use this simple hopping test as an additional method to determine the presence of FAI.