Identification of time-varying dynamics of the human triceps surae stretch reflex: I. rapid isometric contractions

A new method for the identification of time-varying systems has been used to track the changes in the gain of the triceps surae stretch reflex during rapid, voluntary contractions performed under isometric conditions. Our results indicate that the gain of the sketch reflex closely follows the mean level of EMG suggesting that under these conditions reflex gain and motor drive are closely linked.