This study will consist of electromyography (surface and intramuscular), peripheral nerve stimulation, and transcranial magnetic stimulation, electrical stimulation, of the hand, arm, leg, and foot representation of the primary motor cortex, as well as MRI scans of the brain. The investigators will examine the physiological measurements of upper and lower extremity muscles (such as in the first dorsal interosseous (FDI), biceps brachii (BIC), anterior deltoid (AD), tibialis anterior (TA), hamstring (HAMS) and quadriceps (QUAD)). This study may occur at the Miami Project to cure Paralysis at the University of Miami. The investigators will include subjects between the ages of 18 and 85, both healthy controls and individuals with chronic spinal cord injuries that occurred at least 6 months prior to recruitment. Both healthy controls and those with spinal cord injuries will be able to perform small hand and arm movements and small leg and foot movements. The primary outcome measures of this study are muscle responses to stimulation with magnetic pulses using TMS and electrical stimulation of a peripheral nerve in the arm or leg. The investigators propose to enhance the recovery of motor function by using new protocols of high frequency non-invasive repetitive TMS (rTMS) and motor training. Repetitive TMS will be used during hand, arm, leg and foot movements in a task-dependent manner to induce cortical plasticity and enhance voluntary output of the muscles associated with those movements. Second, rTMS will be applied in a task-dependent manner during a visuo-motor training task that also involves movements of the hands, arms, legs or feet.