Meeting Abstract

LBS1.6  Thursday, Jan. 3  Reading physiological signatures in electromyograms WAKELING, James M; Simon Fraser University, Canada wakeling@sfu.ca

Myoelectric signals are interference patterns containing information from the active motor units. Each motor unit action potential (MUAP) has a characteristic shape and conduction velocity and occurs at a defined time. These features are encoded by the time-frequency properties within the signal. The shape and conduction velocity of the MUAPs are determined by physiological factors such as muscle temperature, length, fatigue status and fibre-type. The myoelectric spectra contain information about both the firing patterns of the motor units and their constituent MUAPs. Furthermore anatomical parameters such as the positioning of the motor units and the dimensions of the muscle and overlying tissues can affect the signal recorded in an electromyogram. Time-frequency signal processing techniques such as wavelet analysis can be used to decode the physiological information contained within the electromyogram. Recent studies have shown how the activity in different types of motor unit can be characterised by their spectral components in the electromyogram for both fine-wire and surface recordings. These methods have made it possible to test how the recruitment of different types of motor unit is linked to the mechanical demands on the muscle during locomotion.