Percutaneous electrode assemblies, systems, and methods make possible the providing of short-term therapy or diagnostic testing by providing electrical connections between muscles or nerves inside the body and stimulus generators or recording instruments carried outside the body. The percutaneous electrodes include a flexible body having an electrically conductive region, a tissue penetrating region, and a percutaneous lead electrically coupled to the electrically conductive region. An anchoring element is positioned on the flexible body to resist movement of the electrically conductive region within tissue. An introducer is sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue, and accommodates advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position.