Gait Event Detection and Gait Parameter Estimation from a Single Waist-Worn IMU Sensor

Changes in gait are associated with an increased risk of falling and may indicate the presence of movement disorders related to neurological diseases or age-related weakness. Continuous monitoring based on inertial measurement unit (IMU) sensor data can effectively estimate gait parameters that reflect changes in gait dynamics. Monitoring using a waist-level IMU sensor is particularly useful for assessing such data, as it can be conveniently worn as a sensor-integrated belt or through a smartphone application. Our work investigates the efficacy of estimating gait events and gait parameters based on data collected from a waist-worn IMU sensor. Results are compared to measurements obtained using a GAITRite\textsuperscript{\textregistered} system as reference. We evaluate two machine learning (ML) based methods. Both ML methods are structured as sequence-to-sequence models (Seq2Seq). The efficacy of both approaches in accurately determining gait events and parameters is assessed using a dataset consisting of 17,643 recorded steps from 69 subjects, who performed a total of 3,588 walks, each covering approximately 4 meters. Results indicate that the CNN-based algorithm outperforms the LSTM method, achieving a detection accuracy of 98.94% for heel strikes and 98.65% for toe offs, with a mean error of 0.09 ± 4.69 cm in estimating step lengths.