Estimating 3D GRF Using a Minimal Sensor Setup: Exploiting the Concept of VPP

This paper introduces a novel method for the estimation of 3D Ground Reaction Forces (GRF) using a minimal sensing setup, aiming to overcome the limitations associated with conventional subject-specific approaches. Specifically developed for activities where the Center of Mass (CoM) closely aligns with the pelvis position, such as without bending of the torso segment, the proposed approach includes seven Inertial Measurement Units (IMUs), Pressure Insoles (PIs), and a biomechanical constraint based on the Virtual Pivot Point (VPP) concept. The method's performance was evaluated using data from eight healthy individuals engaged in various movements, including walking, jumping, landing, and lunging. Results demonstrate good accuracy in estimating anteroposterior (AP) and vertical (V) components of GRF. Some limitations were found in the mediolateral (ML) component, especially during jumping and fast walking (FW), highlighting the need for improved filtering techniques to enhance the accuracy of the total GRF estimation. This study serves as a proof of concept, with future work aimed at refining accuracy, minimizing the set of IMUs employed, and exploring applications for Activities of Daily Living (ADL) among patients affected by Osteoarthritis (OA). The proposed approach presents a promising direction in biomechanical research intending to develop a more practical system for clinical settings.