Prophylactic ankle bracing reduces rearfoot motion during sudden inversion

The purpose of this study was to evaluate the effects of ankle bracing on rearfoot angular displacement and angular velocity during a sudden inversion movement. A 1 x 3 factorial design was used. The single independent variable was ankle brace condition with three levels: semi-rigid, lace-up and control. The two dependent variables were rearfoot average angular displacement and average angular velocity. Twenty-four healthy volunteers participated in this study. A motion analysis system was used to capture, model and calculate two-dimensional rearfoot motion while the subjects' ankle/foot complex was inverted to 35 degrees on a platform device. All subjects performed five trials of each ankle brace condition, and the average of these trials was used for statistical analysis. The semi-rigid brace significantly reduced rearfoot angular displacement and angular velocity compared with the lace-up (P<0.05) and control conditions (P<0.05). Additionally, the lace-up style brace demonstrated significantly less rearfoot angular displacement and angular velocity compared with the control condition (P<0.05). These results demonstrate that a semi-rigid ankle brace is more superior then a lace-up style brace in limiting rearfoot angular displacement and angular velocity. Moreover, the lace-up style brace offers significant restriction of these measures compared with no support.