In a single surgical procedure electrodes will be inserted into muscles of the trunk and hip musculature. The electrode leads are connected to a stimulator/telemeter located in the abdomen. After a typical post-operative period of two to five days, neuroprosthesis recipients will be discharged to home for two to six weeks of restricted activity to promote healing of all surgical incisions. After a period of exercise and training, functional use of the neuroprosthesis will begin. Laboratory assessments of strength, balance, and functional abilities with and without the system, as well as the technical performance of the implanted components will be evaluated.