Real-time estimation of individual muscular forces of the lower limb using wearable sensors

In this paper, individual muscular forces of the lower limb are estimated in real-time by inverse dynamics-based static optimization with a wearable sensor system. The wearable sensor system consists of inertial measurement units (IMUs) and manually developed ground reaction force (GRF) sensors. Joint torques of the lower limb during walking are calculated in real-time by applying inverse dynamics to a two dimensional musculoskeletal model in the sagittal plane with the measured motion data and predetermined body segment parameters. Then, the forces of nine muscle groups of the lower limb are estimated by static optimization using the joint torques. The results were compared with the estimated muscular forces using a vision motion capture system with a force plate.