The aim of this randomized, cross-over, multi-center, intention-to-treat, open-label study study is to determine the benefits of the NEUROSWING device on gait speed in patients with dorsal and/or plantar flexor deficits, compared with the use of a carbon orthosis. Each patient will benefit in random order from a 14-day investigation period with the NEUROSWING device and a 14-day control period with a carbon orthosis. These two 2-week periods will be separated by one week, during which no orthosis will be worn and no evaluation will be carried out. Patients will be randomized to determine which phase they will start with. The primary endpoint is walking speed, which will be measured by comparing the results of the 10-meter walk test. For the secondary endpoints, patients will be assessed using the Functional Gait Assessment (FGA), the 6-minute test and an analysis system that will analyze other gait parameters (duration of the different phases of the gait cycle, cadence and step length). In order to carry out the assessments, each patient included will have 12 visits spread over 5 weeks.