Objective: The purpose of this study was to demonstrate the reliability of ankle musculature latency, peak and time of activation measurements on a tilting platform (APS) to sudden external frontal perturbation under different conditions. Design. The latency, peak & time of activation of 10 healthy and 10 patients with functional ankle instability(FAI) was examined in an methodological study.

Materials & Methods: The latency, peak and time of activation after sudden inversion of the ankle were determined by APS and surface EMG.

Results: The range of ICC Values for latency of Peroneus Longus (0.71-0.97) ,Tibialis Anterior (0.75-0.99), Peroneus Brevis (0.83-0.99) and Soleus (0.97-0.99) were obtained.These values for peak of activation of Peroneus Longus (0.81-0.99), Tibialis Anterior (0.9-0.99), Peroneus Brevis (0.64-0.99), Soleus(0.98-0.99)and for time of activation of Peroneus Longus (0.89-0.99) Tibialis Anterior (0.71-0.99) Peroneus Brevis (0.91-0.99) and Soleus (0.69-0.99) were calculated.

Conclusion: Determination of The latency, peak and time of activation was proven as a reliable measurement method.