Biomechanical Difference between Chronic Ankle Instability Individuals and Healthy Individuals during Landing on Flat, Inverted and Combined Surfaces

Lateral ankle sprains most frequently occurs during sports. Individuals who experienced a first time ankle sprain had a high reoccurrence rate and residual symptoms and functional instability leading to chronic ankle instability (CAI). The purpose of this study was to investigate kinematic and kinetic differences between CAI individuals and healthy subjects in single-leg drop landing on a flat surface, an inverted surface and a combined surface of inversion and plantarflexion. A total of 17 subjects (6 subjects with chronic ankle instability, 11 healthy subjects) performed five trails in each of four dynamic movement conditions of drop landing from a height of 30 cm onto a force plat form: double leg landing, single-leg drop landing on flat surface, inversion surface of 25 degrees and combined surfaces of 25 degrees of inversion and 25 degrees of plantarflexion. A nine-camera motion analysis system was used to capture the movement of dynamic testing. A 2 × 4 (ankle stability × surfaces) repeated measures ANOVA was used to evaluate the variables for dynamic testing (p