Inertial sensor network for determining ankle-foot segment dynamics and its asymmetries in gait

Abstract Purpose Through devices and techniques developed in instrumentation, it is possible to create low-cost systems to diagnose variables related to human movement. These systems can assist in rehabilitating individuals, analyzing pathologies, and enhancing performance. This work presents the development of an inertial sensor network dedicated to characterizing the spatial dynamics of the ankle-foot segment and analyzing asymmetries in human gait. Methods The system consists of four Micro Electro-Mechanical Systems (MEMS) inertial modules strategically positioned on the ankle-foot segment. Each module includes a triaxial accelerometer and gyroscope, and their data are controlled through an Inter-Integrated Circuit (I²C) bus using a microcontroller. Anomalies in human gait and observations of how the ankle-foot segment behaves during the phases of the gait cycle were determined using the system. Results Factoring the maximum angles a segment can reach on each global axis, the X and Y axes exhibited greater relative deflections due to center of pressure variation and gait asymmetries. Taking into account the XY plane that makes up the transverse region of the foot, the resulting acceleration presented angles close to 25° in relation to the tibial axis during initial contact. Our results indicate that inertial sensors can be applied to determine the spatial dynamics of the ankle-foot segment during gait. The X and Y axes exhibited greater relative deflections .Given the commercial systems high cost, the use of low-cost capacitive sensors offers a good alternative for assessing human movement. Conclusion This study demonstrated that it is possible to assess the spatial dynamics of the ankle-foot segment during gait using a low-cost system, enabling more physiotherapy clinics to access this technology.