Locomotor Training With Testosterone to Promote Bone and Muscle Health After Spinal Cord Injury

Inclusion Criteria: * Men \>18 years of age * Diagnosis of an incomplete SCI involving spinal segments L1 or above or a clinically complete SCI involving spinal segments T2-L1, with upper motor neuron injury signs (i.e., spasticity, hypertonicity) for \>60-days * Low serum total testosterone (\<300 ng/dL), bioavailable testosterone (\<110 ng/dL), or free testosterone (\<46 pg/mL or \<4.6 ng/dL) * Presence of one or more sign or symptom that may be related to low testosterone, including: loss of body hair or reduced shaving, very small testes (\<6 mL), reduced sexual desire (libido) and activity, decreased spontaneous erections (e.g., morning erections) or erectile dysfunction, breast discomfort or gynecomastia, height loss, low-trauma fracture, or low BMD, hot flushes or sweats, decreased energy, motivation, initiative, or self-confidence, fatigue or irritability, feeling sad or blue, having a depressed mood, or having a persistent low-grade depressive disorder, poor concentration or memory, sleep disturbances or increased sleepiness, mild unexplained anemia (normochromic or normocytic), reduced muscle bulk, strength, or physical performance, Increased body fat or body mass index, any other sign or symptom commonly associated with low testosterone * Locomotor dysfunction, definted as self-selected walking pace ≤1.0 m/s on a 10mWT, either with or without gait devices or braces and with or without assistance, or as self-selected walking pace \>1.0 m/s with reliance on a gait d…