Reliable Gait Parameters from a Lower-Back IMU for Fall Risk Assessment

Accurate and reliable gait assessment is essential for fall prevention, particularly among older adults. Inertial measurement units (1MUs) represent a portable and affordable alternative to traditional motion capture systems. This study investigates the reproducibility of gait parameters obtained from a single lower-back IMU during walking at three self-selected speeds: slow, normal, and fast. After signal preprocessing, we extracted features related to gait intensity (e.g., speed, cadence), variability (e.g., stride duration variation), and energy expenditure (via estimated VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>). Reproducibility was evaluated using the Intraclass Correlation Coefficient (ICC2). Results showed that spatiotemporal parameters such as speed, cadence, and stride length were highly reliable, especially at normal and fast speeds (ICC > 0.75). However, variability metrics and medio-lateral power were less consistent at slow speeds, likely due to reduced motion amplitude. These findings support the use of IMUs for gait monitoring in both clinical and research settings. Additionally, by aligning the analysis with the Timed Up and Go (TUG) test, this approach enhances a standard geriatric evaluation with richer biomechanical insights to better inform fall-risk assessment.