The central nervous system (CNS) exhibits remarkable plasticity throughout life. The physiological changes in the CNS that occur due to plasticity allow us to perform new skills and old ones more effectively and efficiently over time. Recently, it has been demonstrated that plasticity can be used to help people recover motor function after spinal cord injury (SCI), stroke, or other neurodegenerative diseases. Following injury or illness, neuronal pathways are disrupted, leading to exaggerated reflexes and motor impairments. Rehabilitation methods can help restore motor function by triggering beneficial plasticity (i.e., neuronal and/or synaptic changes that improve motor functions). H-reflex operant conditioning that triggers beneficial plasticity is one promising new therapeutic approach to motor rehabilitation. In this paradigm, participants are operantly conditioned to change the size of abnormal reflexes associated with motor deficiencies (either increased or decreased as needed), which consequently improves movement. H-reflex operant conditioning has no known adverse side effects and it can complement other therapies. Two present limitations of H-reflex operant conditioning are its success rate and the length of time required to complete the conditioning. Given that the beneficial plasticity induced by this paradigm is modeled to start in the sensorimotor cortex, we designed an enhanced H-reflex operant conditioning system that provides people with brain-computer interface (BCI)-based feedback on activity from this region of the brain. We hypothesize that by guiding this critical first stage of plasticity, it should be possible to enhance the efficacy and efficiency of this paradigm. This thesis is organized as follows. Chapter 1 introduces the H-reflex operant conditioning and the logic for our enhanced H-reflex operant conditioning system. Chapters 2 and 3 describe experiments conducted to identify and train participants to use our BCI-based feedback system. Five participants completed the training; four of these participants learned to use the BCI with better than 70% accuracy and three of these four participants significantly improved their accuracy with training. Chapter 4 lays out the design of the enhanced H-reflex conditioning system. Finally, Chapter 5 presents plans for experiments to test the system when human-based research is able to safely resume following the global COVID-19 pandemic and potential directions of future work.