Estimating 3D Ground Reaction Forces During Daily Activities: A Reduced Sensor Setup and Virtual Pivot Point Approach

Area of Science:

• Biomechanics
• Biomedical Engineering
• Wearable Technology

Background:

• Ground reaction forces (GRF) are crucial for joint loading assessment, especially in osteoarthritis (OA) patients.
• Traditional GRF measurement using force plates is limited to laboratory settings.
• A portable and accurate method for real-world GRF estimation is needed.

Purpose of the Study:

• To present a novel method for estimating 3D GRF during activities of daily living (ADL).
• To utilize a minimal sensor setup (IMUs and pressure insoles) with the Virtual Pivot Point (VPP) concept.
• To enable portable joint loading estimation for real-world monitoring.

Main Methods:

• Collected 3D GRF data using three IMUs and pressure insoles during various ADL (walking, stairs, sit-to-stand).
• Employed the Virtual Pivot Point (VPP) biomechanical concept to distribute GRF between feet.
• Validated the system's accuracy against established methods.

Main Results:

• The novel system achieved high accuracy for most ADL, with relative RMSE < 15% and correlation coefficients > 0.7.
• Accuracy was slightly reduced for sit-to-stand movements during the Timed Up and Go (TUG) test.
• The minimal sensor setup demonstrated performance comparable to more extensive systems.

Conclusions:

• The proposed method offers an accurate and portable solution for estimating 3D GRF during ADL.
• This technology can facilitate real-world joint loading monitoring for individuals with OA and healthy subjects.
• Open-source code and data are available, promoting further research and application.