Subject matter includes a method comprising: generating a first electrical signal having a time-varying waveform； generating a second electrical signal having a time-varying waveform, wherein a sum of the first electrical signal and the second electrical signal comprises a target electrical signal having a waveform to generate substantial motor movement of the one or more muscles in the patient； and applying the first electrical signal via a first electrode and the second electrical signal via a second electrode to a particular location on the patient, wherein the first electrode and the second electrode are on a single electrode pad.
