For most patients with an incomplete spinal cord injury, gait rehabilitation plays a key role in functional recovery. However, few methods are available to reliably assess gait function during rehabilitation. Therefore, a study was initiated to develop a gait assessment interface that is user-friendly, time-efficient, and based on objective data and intuitive data visualizations helps physicians and physiotherapists select and evaluate interventions for patients. The paper focuses on the first phase of the design process, user research, and how user-centered design was used to identify users’ needs and expectations, and the context wherein the gait assessment interface would be used. This was done through conducting focus group sessions with professional users (physicians and physiotherapists) and using interactive activity boards to obtain answers and facilitate discussion. The information obtained, as well as user-centered design practices, will be used throughout the further development of the gait assessment interface.