Influence of a multidirectional overground body weight support system on walking-related tasks in typically developing children and adolescents

Introduction The RYSEN is a multidirectional body weight support system for overground gait rehabilitation. It provides vertical unloading and enables unrestricted overground walking while preventing falls. While the RYSEN seems highly transparent in healthy adults, i.e., users only feel small forces from the device in response to their movements, we explored how the RYSEN affects the execution of various walking-related tasks in typically developing children and adolescents (TDCA). Methods Nineteen TDCA, weighing 19.3–57.3 kg, participated. They performed several walking-related tasks in a randomized order using the RYSEN exercise modes: walking, stairs, stand up, sit down, and balance. They moved in the RYSEN with 20% body weight unloading. A 3D motion capture system collected movement parameters. Force plates recorded ground reaction forces. We compared various parameters between the RYSEN and no-RYSEN conditions and correlated the percentile differences in parameters between these conditions with the participants' body weight. Participants also completed several questions. Results Walking: compared to the no-RYSEN condition, TDCA walked slower in the RYSEN, with shorter steps and greater step length variability ( p ≤ 0.008). Along a curved path, TDCA walked with larger deviations ( p ≤ 0.004). Stairs: participants walked slower and with wider steps when stepping on and off a higher-level surface ( p < 0.001). Stand up and sit down: these tasks took longer with deviating movement patterns and ground reaction forces, particularly when sitting down ( p < 0.001). During the dynamic balance tasks, the TDCA reached further forward and sideways in the RYSEN balance mode ( p ≤ 0.003). Effect sizes were generally medium to large. Some correlation analyses, for example, those that included the percentile differences of walking speed and step width during straight walking, showed that lighter children were more affected than heavier children. The TDCA generally considered the RYSEN to facilitate most tasks. Conclusions Therapists should be aware that each RYSEN exercise mode influences the performance of walking-related tasks differently and that some modes impact lighter children more than heavier children. Our next step is to evaluate the applicability of the RYSEN in the target population, i.e., children and adolescents with gait disorders.