Real-Time OpenSim via IMUs for Full Body Kinematics During Gait, Sports, Exercise, and Dance Movements

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Wearable Technology

Background:

• Aging populations increase demand for healthcare services.
• Traditional rehabilitation centers face barriers like cost, time, and patient discomfort.
• Home-based rehabilitation is a viable alternative, but lacks real-time kinematic monitoring.

Purpose of the Study:

• To develop and validate a real-time, wireless, portable system for computing full-body kinematics using OpenSim.
• To assess the accuracy of this system compared to optical motion capture for various physical activities.

Main Methods:

• Twenty-two subjects performed diverse exercises wearing 12 SageMotion inertial measurement units (IMUs).
• Real-time (20 Hz) and offline (100 Hz) IMU kinematics were computed and compared to optical motion capture.
• Accuracy was quantified using Root Mean Square Error (RMSE) and latency was measured.

Main Results:

• Real-time walking and stair climbing showed high accuracy (median RMSE of 5.3 deg).
• Lumber rotation was the most accurate joint angle (median RMSE of 2.7 deg), with an overall median RMSE of 7.4 deg across all activities.
• Mean latency was 31.7 ms, with minimal difference (mean RMSE of 0.7 deg) between real-time and offline IMU estimations.

Conclusions:

• The proposed wireless IMU system provides accurate real-time full-body kinematic assessment.
• This technology can significantly enhance remote rehabilitation by enabling rapid assessment and biofeedback.
• Potential to improve patient assessment and treatment outcomes in clinical and remote settings.