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Journal of Sensors
Volume 2017 (2017), Article ID 6747921, 14 pages
Research Article

Estimation of Individual Muscular Forces of the Lower Limb during Walking Using a Wearable Sensor System

Department of Mechanical Engineering, UNIST, Ulsan, Republic of Korea

Correspondence should be addressed to Joonbum Bae;

Received 28 October 2016; Revised 24 February 2017; Accepted 26 March 2017; Published 22 May 2017

Academic Editor: Jaime Lloret

Copyright © 2017 Suin Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Although various kinds of methodologies have been suggested to estimate individual muscular forces, many of them require a costly measurement system accompanied by complex preprocessing and postprocessing procedures. In this research, a simple wearable sensor system was developed, combined with the inverse dynamics-based static optimization method. The suggested method can be set up easily and can immediately convert motion information into muscular forces. The proposed sensor system consisted of the four inertial measurement units (IMUs) and manually developed ground reaction force sensor to measure the joint angles and ground reaction forces, respectively. To verify performance, the measured data was compared with that of the camera-based motion capture system and a force plate. Based on the motion data, muscular efforts were estimated in the nine muscle groups in the lower extremity using the inverse dynamics-based static optimization. The estimated muscular forces were qualitatively analyzed in the perspective of gait functions and compared with the electromyography signal.