The present invention is a portable isometric exercise device with resistance generated by a spring force including an electronic light or sound indicator to signal that a constant force level is being maintained. When a force is applied to the spring and a desired level of resistance is achieved, a continuous signal will be generated to advise the user that the isometric force exercise is being maintained. If the force is reduced, the signal will terminate to advise the user that the user has not maintained the required level of resistance.