A system for monitoring muscle activity of a biological subject, the system including at least one garment including a number of arrays of electrodes positioned on the garment so that when the garment is worn by a subject in use, the electrodes contact skin of the subject and generate electrical signals indicative of electrical potentials within respective muscles of the subject and at least one electronic processing device that processes signals from the electrodes in each electrode array to determine a muscle activation for parts of the respective muscles and uses the muscle activation to determine at least one muscle indicator indicative of muscle activity of the subject.