Background Chronic ankle instability (CAI) is a frequently reported residual outcome after an acute ankle sprain. Balance training is common daily practice in treatment of CAI, but its effect on CAI associated mechanisms as postural control remains unclear.

Objective The aim of this study was to establish the presence of postural deficits in subjects with CAI and assess the effect of an 8-week balance training program on dynamic postural control.

Design Case-control baseline group characteristics were determined and intervention effects were evaluated.

Setting All subjects were tested in a laboratory setting and the intervention group performed a home-based balance protocol.

Participants Data were collected for 74 recreationally active subjects (43 subjects with CAI and 31 controls).

Interventions Subjects with CAI performed an 8-week progressive, home-based balance protocol. Subjects had to perform these balance exercises 3 times a week. Eighteen subjects with CAI first served as control group without intervention, before entering the balance program.

Main outcome measurements Postural control was quantified by means of the dynamic postural stability index (DPSI) and its separate directional stability indices (mediolateral, anterior/posterior and vertical). Perceptual outcomes were documented using the FADI and FADI-Sport.

Results At baseline, subjects with CAI displayed higher anterior/posterior (P=.002) and vertical postural instability (P=.001), a poorer DPSI (P<.001), and lower subjective stability scores (FADI and FADI-Sport, P<.001) compared to the control group. After balance training, stability scores improved significantly (FADI p=0.001, FADI-Sport P=.005), although no changes were noted for the stability indices.

Conclusion Subjects with CAI have an impaired postural control. As a treatment modality, balance training exhibits its capability of improving the subjective feeling of instability in subjects with CAI. However, there was no effect on dynamic postural control measured by DPSI.