Wearable system for the measurement of gait cycle kinematic and kinetic signals

Gait analysis is a fundamental tool in biomechanics and rehabilitation, as it evaluates human movements' kinematic and kinetic behavior. For this reason, high-precision devices have been developed. However, these require controlled environments, which generates a deficiency in the capacity of studies related to gait analysis in outdoor and indoor scenarios. Therefore, this article describes the development and testing of a wearable system to measure gait cycle kinematic and kinetic parameters. The methodology for the development of the system includes the assembly of modules with commercial surface electromyography (sEMG) sensors and inertial measurement sensors, as well as the use of instrumented insoles with force-resistive sensors, and the design of the software to acquire, process, visualize, and store the data. The system design considers portability, rechargeable battery power supply, wireless communication, acquisition speed suitable for kinematic and kinetic signals, and compact size. Also, it allows simultaneous assessment of sEMG activity, hip and knee joint angles, and plantar pressure distribution, using a wireless connection via Wi-Fi and user datagram protocol for data transmission with a synchronization accuracy of 576 μs, data loss of 0.8%, and autonomy of 167 min of continuous operation, enabling uninterrupted data acquisition for gait analysis. To demonstrate its performance, the system was tested on 10 subjects without any neuromusculoskeletal pathology in indoor and outdoor environments, evaluating relevant parameters that facilitate a comprehensive analysis of gait in various contexts. The system offers a reliable, versatile, and affordable alternative for gait assessment in outdoor and indoor environments.