--Disease Characteristics-- Low cervical or thoracic spinal cord injuries (C6-T12) Must be skeletally mature ASIA impairment scale A (complete motor and sensory deficits), B (sensory sparing), or C (motor and sensory sparing) Intact lower motor neurons Greater than 6 months since injury Range of motion within normal limits --Patient Characteristics-- Renal: No renal compromise Cardiovascular: No cardiac abnormalities No circulatory compromise Pulmonary: No pulmonary compromise Other: No acute or chronic psychological problems or chemical dependency No acute orthopedic complications (scoliosis, history of spontaneous fractures, dislocations, etc.) No acute medical complications (no skin breakdowns, uncontrolled seizures, immunological compromise, etc.)