Validity and reliability assessment of joint angle measurement using inertial sensors placement on the examiner

• Published in: Japanese Journal of Community-based Comprehensive Physical Therapy Vol. 3; pp. 77 - 85
• Main Authors: JONO, Yasutomo, NODA, Yuki, MAEDA, Yoshiki, YAMAMOTO, Hidemi, IKEDA, Koji
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Community-based Comprehensive Physical Therapy 31.03.2024
• Subjects: coefficient of multiple correlation; inertial measurement unit; inertial sensor; reliability; validity
• ISSN: 2758-0318
• DOI: 10.57351/jjccpt.JJCCPT23005

Purpose: This study aimed to validate and assess the reliability of IMUrater, a method for measuring joint angles by placing Inertial Measurement Unit (IMU) sensors on the measurer's body.Methods: Sixteen healthy adults were included, and the validity and reliability of IMUrater were compared with an optical motion capture (OMC) system using cameras for motion analysis.Results: The coefficient of multiple correlation (CMC) and root mean square error (RMSE) between the IMUrater and the OMC-based method were 0.93 and 31.20 degrees, respectively. Within sessions, IMUrater showed a CMC of 0.95, a RMSE of 19.40 degrees, and an intraclass correlation coefficient (ICC) of 0.92, while between sessions, the values were 0.85, 35.74 degrees, and 0.19, respectively.Conclusion: IMUrater demonstrated high validity in relative joint angles. Within-session reliability was high, with strong agreement in time series waveform data indicated by CMC. However, between-session reliability showed lower agreement, with substantial discrepancies observed in absolute angle measurements.