Evaluation of Activation Mechanism of Ankle Muscles During Upright Stance Push-recovery

Studying the neuromuscular control mechanism of the ankle joint is very important for revealing upright balance dynamic properties. This paper aims at the evaluating the activation mechanism of ankle joint muscles in the case where the human upright stance is disturbed. To this end, this paper first combines the stretch reflex control with force feedback control to establish muscle reflex control model. Then, the established model is implemented to predict muscle activation levels of multiple subjects when they are disturbed. The disturbance is designed by releasing sandbags from the different height to hit on the back of subjects. The real-time simulator is used to collect the surface electromyography (sEMG) signals of the tibialis anterior (TA), gastrocnemius (GAS) and soleus (SOL) muscles as well as the ankle joint kinematics and dynamic data synchronously. Also, the parameters of the muscle reflex model are obtained and optimized by parameter identification based on particle swarm optimization algorithm (PSO). The experimental data are used as an input of the model to predict the muscle activation levels. Finally, the validity of the muscle reflex control model is verified by experimental tests and data analysis.