Real-Time Wearable Electrogoniometry System for Measuring Range of Motion in Rehabilitation Applications

This article presents a wearable, low-cost, and high-accuracy electrogoniometry system designed for the dynamic measurement of range of motion (ROM). The system integrates two-axis capacitive flex sensors attached to the joints in both the upper and lower limbs (i.e., shoulder, elbow, hip, knee, ankle) through a modular, 3-D-printed framework. The electrogoniometry system aims to detect movement accurately for clinical purposes (e.g., evaluating the onset of diseases that affect mobility) and to control innovative treatment techniques such as precision electrical muscle stimulation (EMS) systems. Following ROM measurement guidelines, the system was successfully validated for accuracy by comparison with video-based motion capture (VMC) software across all aforementioned joints. The proposed system (PS) achieved root mean square error (RMSE) values below 4°, maximum ROM difference (MRD) below 2.5°, correlation coefficients of 99% or higher, and Bland–Altman analysis results of 0.644° ± 4.786°.