Postural control deficits in participants with functional ankle instability as measured by the balance error scoring system

Objective: To determine if postural control deficits are present in participants with functional ankle instability (FAI) as measured by the Balance Error Scoring System (BESS). Design and Setting: We used a between-groups design to assess postural control. All testing was conducted in a university athletic training facility. Participants: Sixty collegiate Division I athletes were included in this study. Thirty participants had functional ankle instability and thirty participants had no history of ankle injuries. Main Outcome Measurements: Postural control was measured using the BESS. The BESS test battery requires participants to stand unsupported on two different surfaces (firm and foam) in three different stances (double, single, and in tandem). Each condition lasted 20 seconds. The number of errors were calculated for each individual condition and then summed to produce a total BESS score. Results: We found a significant group by condition interaction (F-5,F-290 = 5.12, P < 0.001) and significant main effects for group (F-1,F-58 = 16.01, P < 0.001) and condition (F-5,F-290 = 228.88, P < 0.001). Post hoc analyses revealed that subjects with functional ankle instability scored more errors (poorer balance) on the single stancefirm condition (2.9 +/- 2.1 versus 1.6 +/- 1.3 errors), tandem stancefoam condition (4.3 +/- 2.4 versus 2.7 +/- 1.6 errors), single stancefoam condition (7.0 +/- 1.6 versus 5.6 +/- 1.8 errors), and total BESS score (15.7 +/- 6.0 versus 10.7 +/- 3.2). Conclusions: Postural control deficits were identified in participants with functional ankle instability using the BESS. These deficits could be a contributing factor to the repeated episodes of instability and giving way that often occurs following an inversion ankle sprain. These results suggest the BESS, traditionally used for monitoring recovery from mild head injury, may also be useful in screening athletes for postural deficits following lower extremity injury.