RESTRICTION OF FOOT SUPINATION BY ANKLE BRACES IN SUDDEN FALL SITUATIONS

Objective. To investigate the restriction of foot supination in differ ent shoe orthotic combinations for unexpected ankle turns. Design. A s upination platform was used to experimentally induce sudden ankle turn s. Background. This study expanded on previous investigations of the e ffectiveness of different ankle braces and the influence of shoe mater ial on foot supination. Methods. For 21 male subjects pressure distrib ution data, achilles tendon angle, and supination velocity were collec ted. 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. Addit ionally, subjects rated their perceived supination movement of the foo t.Results, Between experimental conditions no large differences for th e pressure distribution patterns were found. Three of the ankle braces reduced foot supination as well as supination velocities. More than t wo times lower supination values were measured for a footwear conditio n in which the upper material was cut away. Already during the free-fa ll most ankle braces caused a substantial reduction of foot inversion. Conclusion. The experiments demonstrated the influence of the upper m aterial of a shoe and different orthotics on foot supination. Biomecha nical measurements are necessary because of limited capabilities of su bjects in detecting subtalar angular motions. Relevance This study inv estigated the effectiveness of different shoe conditions and ankle bra ces under experimental conditions that simulated unexpected ankle turn s, the most frequent causes of sport injuries. The results of the stud y provide insights into which factors influence the amount of foot sup ination during unexpected ankle turns. (C) 1997 Elsevier Science Ltd.