BACKGROUND:Neural plasticity may contribute to motor recovery following spinal cord injury(SCI):In rat models of SCI with respiratory impairment,acute intermittent hypoxia(AIH) strengthens synaptic inputs to phrenic motor neurons,thereby improving respiratory function by a mechanism known as respiratory long-term facilitation.Similar intermittent hypoxia-induced facilitation may be feasible in somatic motor pathways in humans. OBJECTIVE:Using a randomized crossover design,the authors tested the hypothesis that AIH increases ankle strength in people with incomplete SCI.