1. An external defibrillator selectably usable in one of a therapy mode and a training mode, when in the training mode, having a plurality of training state notifications, and adapted for electrical coupling with an electrode arrangeable on a release liner, the electrode electrically conductive and configured for placement on a subject, comprising: an energy source; an electrode interface responsive to the electrode; an energy delivery system operable to selectively deliver electrical energy from the energy source to the electrode via the electrode interface; a state identifier, identifying, when the electrode is electrically coupled to the electrode interface, a degree of electrical connectivity along an electrical path including the electrode; a controller, operative in the training mode, prior to placement of the electrode on the subject, to advance the external defibrillator from a first training state to a second training state when the state identifier identifies a predetermined degree of electrical conductivity along the electrical path; and a user interface, operative in the training mode to issue a training state notification indicating that the external defibrillator has advanced from the first training state to the second training state.