Restriction of foot supination by ankle braces in sudden fall situations

OBJECTIVE: To investigate the restriction of foot supination in different shoe orthotic combinations for unexpected ankle turns. DESIGN: A supination platform was used to experimentally induce sudden ankle turns. BACKGROUND: This study expanded on previous investigations of the effectiveness of different ankle braces and the influence of shoe material on foot supination. METHODS: For 21 male subjects pressure distribution data, achilles tendon angle, and supination velocity were collected. A comparison between a shoe with cut upper material and an intact shoe was done to show the influence of upper material on supination. The effectiveness of four different orthotics inside of an intact shoe were tested in comparison to the same shoe without ankle brace. Additionally, subjects rated their perceived supination movement of the foot. RESULTS: Between experimental conditions no large differences for the pressure distribution patterns were found. Three of the ankle braces reduced foot supination as well as supination velocities. More than two times lower supination values were measured for a footwear condition in which the upper material was cut away. Already during the free-fall most ankle braces caused a substantial reduction of foot inversion. CONCLUSION: The experiments demonstrated the influence of the upper material of a shoe and different orthotics on foot supination. Biomechanical measurements are necessary because of limited capabilities of subjects in detecting subtalar angular motions. RELEVANCE: This study investigated the effectiveness of different shoe conditions and ankle braces under experimental conditions that simulated unexpected ankle turns, the most frequent causes of sport injuries. The results of the study provide insights into which factors influence the amount of foot supination during unexpected ankle turns.