Available online at www.sciencedirect.com Journal of Science and Medicine in Sport 15 (2012) 574–579 Original research Dorsiflexion and dynamic postural control deficits are present in those with chronic ankle instability Matthew C. Hoch a,∗ , Geoffrey S. Staton b , Jennifer M. Medina McKeon b , Carl G. Mattacola b , Patrick O. McKeon b a Department of Human Movement Sciences, Old Dominion University, Student Recreation Center, Norfolk, VA, United States b College of Health Sciences, Division of Athletic Training, University of Kentucky, United States Received 2 November 2011; received in revised form 13 February 2012; accepted 24 February 2012 Abstract Objectives: To determine if differences in weight-bearing ankle dorsiflexion range of motion (DFROM) and Star Excursion Balance Test (SEBT) reach distances were present between participants with chronic ankle instability (CAI) and healthy individuals. A secondary objective was to re-examine the relationship between these measures in participants with and without CAI. Design: Case–control. Methods: Thirty participants with CAI were matched to 30 healthy participants. All participants performed maximum reach in the anterior, posteromedial and posterolateral directions of the SEBT; as well as, the Weight-Bearing Lunge Test (WBLT) to measure DFROM. Dependent variables included maximal DFROM (cm) and normalized SEBT reach distances (%). Independent t-tests were used for group comparisons (a priori p ≤ 0.05). Simple-linear regression examined the relationship between the WBLT and each SEBT direction. Results: Significant differences were detected between groups for the WBLT (CAI: 10.73 ± 3.44 cm, healthy: 12.47 ± 2.51 cm; p = 0.03) and anterior reach distance (CAI: 76.05 ± 6.25%, healthy: 80.12 ± 5.88%; p = 0.01). No differences were identified in posteromedial or posterolateral (ps > 0.70) reach. The WBLT had a significant moderate correlation to anterior reach in both groups (ps < 0.05) but was not significantly correlated to posteromedial or posterolateral reach distance (ps > 0.70). Conclusions: The results indicate that participants with CAI demonstrated less DFROM and anterior SEBT reach distance compared to health controls. Additionally, both groups demonstrated similar correlations between WBLT and SEBT performance. These findings suggest that participants with CAI have alterations in ankle motion which may negatively influence dynamic postural control; however, the relationship between WBLT and SEBT performance is consistent in those with and without CAI. © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Ankle sprain; Joint instability; Rehabilitation 1. Introduction Up to 70% of individuals who sustain a single lat- eral ankle sprain experience residual symptoms including pain and swelling, recurrent episodes of ankle instability, and repetitive ankle sprains which are the hallmark char- acteristics of chronic ankle instability (CAI). 1,2 Although ankle sprains are often considered innocuous injuries, CAI has been associated with long-term consequences such as ∗ Corresponding author. E-mail address: mhoch@odu.edu (M.C. Hoch). post-traumatic ankle osteoarthritis and decreased health- related quality of life. 3,4 A well-documented contributing factor for CAI is deficits in postural control. 5,6 Postural con- trol deficits have been particularly evident in those with CAI when evaluated using dynamic assessment techniques which examine the capacity to maintain stability within the boundaries of the base of support during functional activities. 6,7 Therefore, CAI is a common health condition in physically active individuals and gaining further insight into how dynamic postural control deficits contribute to this multi-faceted health condition may be useful in developing meaningful intervention strategies. 1440-2440/$ – see front matter © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jsams.2012.02.009