Multiple-Input/Single-Output identification of the dynamic relation between EMG and torque at the human ankle during isometric contractions

Generation of torque around a joint usually involves the activation of several agonist muscles and may also involve the co-activation of antagonist muscles. Therefore, a valid model for the dynamic relation between surface EMG (an indirect measured of the muscle´s neural input) and the torque should take the form of a Multiple-Input/Single-Output (MISO) system to account for the contributions of the different muscles. This paper presents a new method to accurately estimate the dynamic EMG/Torque relation when multiple muscles are active simultaneously. Using our method we found that flexor and extensor muscles at the ankle have different dynamic properties.