Effect of Tilted surfaces on Ankle Kinematics and EMG activities in landing

The purpose of this study was to examine the effects of landing on a combined inverted and plantarflexed surface on the ankle kinematics and electromyographic (EMG) activities of the medial gastrocnemius (MG), peroneal longus (PL) and anterior tibialis muscles (TA). Twelve recreational athletes performed five drop landings from an overhead bar of 30 cm height on to each of these surfaces: a flat surface, a 25° inversion surface (inverted), and a combined surface (combined) of 25° inversion and 25° plantarflexion. The three dimensional kinematic variables and integrated EMG (IEMG) of the three muscles were assessed using one-way repeated measures analysis of variance (ANOVA, p < 0.05) and a 3 × 3 (surface × muscle) ANOVA, respectively. The IEMG results showed a significant muscle by surface interaction. The flat surface induced higher TA activity than the two tilted surfaces. The inverted surface produced significantly higher inversion peak angle and velocity than the flat surface, but similar PL activity across the surfaces. The MG IEMG and ankle plantarflexion angle were significantly higher for the combined surface compared to the inverted surface. These findings suggest that compared to inversion, a combination of plantarflexion and inversion provides a more realistic surface for simulating lateral ankle sprains.