“…To address this problem, this study estimates the lower-limb sagittal joint angles during gait based on acceleration and angular velocity, which can be measured using an inertial measurement unit (IMU). Although various sensors such as millimeter-wave radar ( Alanazi et al, 2022 ), fiber optics ( Mohamed et al, 2012 ; Kim et al, 2014 ), electro-goniometer ( Rowe et al, 2000 ; da Silva Camassuti et al, 2015 ), and e-textiles ( Tognetti et al, 2015 ) can estimate the kinematics according to previous studies, IMUs are portable (light and small), incur low cost, exhibit minimal invasiveness, and are not obtrusive ( e.g ., full-body suits) ( Digo, Pastorelli & Gastaldi, 2022 ). Owing to these advantages, portable measurement tools can help recruit larger, more diverse populations in clinical studies.…”