The role of external non-rigid ankle bracing in the prevention of inversion injuries

Ankle bracing is rapidly becoming the accepted method for the prevention of inversion injuries among active individuals suffering from a chronic ankle instability. The purpose of this study was to measure the effectiveness of the non-rigid, Subtalar Stabilizer (STS) ankle brace under conditions similar to an unexpected fall which inextreme circumstances could lead to a lateral ligament injury. The "calcaneal inversion" angles, times, and forces were measured when the subject's right foot, bearing body weight, was suddenly inverted as the trap door of the support platform swung to a side slope of 22°. Thirty subjects, 15 female and 15 male participated in the study. The "overall inversion drop" was divided into two phases, "free-fall" and "loading". The results of the 2 (sex) by 4 (brace condition) ANOVAs followed by post-hoc Tukeys analyses showed the brace significantly (p<0.05) reduced the "calcaneal inversionangle" from 27.4° ± 6.1° to 18.3° ± 6.0° for the "overall drop", significantly lengthened the "inversion time" from 0.140 ± 0.040seconds to 0.184 ± 0.040 seconds for the "overall drop", and significantly reduced the "calcaneal inversion velocity" from 324.6 ±111.9 °/sec. to 165.2 ± 66.5 °/sec. during "loading", and from 278.7± 120.0 °/sec. to 183.0 ± 108.7 °/sec. for the "overall drop". Following exercise which incorporated lateral movements and sprinting, the STS ankle brace continued to provide significant(p<0.05) reduction in the "calcaneal inversion angle and velocity" however it lost some of its original effectiveness. Although the females had a significantly (p