Locomotion Disorder, Neurologic

This pilot study will determine the feasibility of implementing a combinatory rehabilitation strategy involving testosterone replacement therapy (TRT) with locomotor training (LT; walking on a treadmill with assistance and overground walking) in men with testosterone deficiency and walking dysfunction after incomplete or complete spinal cord injury. The investigators hypothesize that LT+TRT treatment will improve muscle size and bone mineral density in men with low T and ambulatory dysfunction after incomplete or complete SCI, along with muscle fundtion and walking recovery in men with T low and ambulatory dysfunction ater incomplete SCI.