Seeks to develop new control systems to restore seated function and enhance the postural stability of the trunk for individuals paralyzed by spinal cord injury (SCI). Systems that provide persons with the ability to sit erect, alter their seated posture, and maintain balance by automatically adjusting stimulation to the paralyzed muscles will be designed, optimized in simulation, and evaluated experimentally in five volunteers with SCI. The project will result in a unique, comprehensive trunk balance control system that extends the capabilities and improves the safety of all currently available trunk neuroprostheses.