 The surgery will be performed at University Hospital to insert the epidural stimulating electrodes. The lead wires will be tunneled subcutaneously to exit 5 centimeters from the incision site. The implantable neurostimulator will be internalized and the connecting wires for the implanted electrodes will be tunneled under the skin and connected with the battery generator that will be placed in the abdominal area. We will repeat the experiments beginning 2-14 days after the surgery both with and without stimulation for 10 - 14 days. During the first two weeks after the surgery, the research participants may be hospitalized at Frazier Rehab Institute to monitor the incision site. We will also identify appropriate stimulation parameters for inducing stepping and standing in combination with manual assistance using body weight support on a treadmill BWST. 