P13 The validity of inertial measurement units (IMU) in three-dimensional lower-body human gait analysis
Letton M, Thom JM and Ward RE
Department of Exercise Physiology, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney Australia
Inertial measurement units (IMUs) are small, cost effective, wearable sensor technology used to record human motion (1), especially useful when remotely analysing movement, including gait patterns, for a range of clinical conditions. Thus, the application of IMUs is broader than optical motion capture, the current ‘gold standard’ technique (2). The aim of this study was to validate Vicon IMUs with optical motion capture during gait. We hypothesized that IMUs would accurately measure joint angle kinematics during gait, as compared to optical motion capture. Methods: IMUs and optical motion capture simultaneously assessed human motion during the gait cycle, in 8 healthy adult volunteers (23.25±2.96 years, BMI 21.76±2.44, mean±SD). IMUs were attached to volunteers at the pelvis, thigh, shank and foot segments. Accelerometer, gyroscope and magnetometer data was sent via Bluetooth to the Vicon Nexus program on a PC. MATLAB was then used to calculate the hip, knee and angle joint kinematics. The average error between the measurement methods was 11.8°±1.5° for hip sagittal ROM, 2.1°±4.1° for knee sagittal ROM, and 8.9°±6.0° for ankle sagittal ROM. Current IMU technology was found to be accurate in recording knee joint kinematics. Further analysis is needed to determine whether hip and ankle joint kinematic data can be accurately obtained using IMUs. Whole body joint kinematic data also needs to be analysed to validate IMUs for possible use in motor impairment/falls risk populations in clinical settings.
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