The invention relates to apparatus for applying pulsed electrical stimulation to a human or animal subject. The apparatus comprises a control circuit having a number of output terminals each of which is connectable to at least one of an array of three or more electrodes (A-D) arranged externally on a body part, such as the leg. The control circuit subdivides the pulses into a plurality of consecutive time periods, and a combination of both spatially and temporally summated current density can be controlled at a given locus within the body part. This is achieved by providing means for selectively connecting, for each time period, each electrode to an anode terminal, a cathode terminal or neither.