Estimation of Human Lower Extremity Musculoskeletal Conditions During Backpack Load Carrying


Department of Mechanical Engineering,Sharif University of Technology


Abstract. This paper focuses on the biomechanical aspects of the human lower extremity loading
condition during backpack load carrying. A biomechanical framework was generated with the aim of
employing a block-oriented structure of Simulink integrated with the Virtual Reality Toolbox of MATLAB
software to provide a simulation study of the musculoskeletal system in a virtual environment. In this case,
a ten-degrees-of-freedom musculoskeletal model actuated with sixteen muscles in each leg was utilized to
simulate movement in the sagittal plane. An inverse dynamics based optimization approach was employed
to estimate the excitation level of the muscles. In addition, distributions of the mechanical power analysis
for lower extremity muscles were carried out to enhance the understanding of human leg morphology
and control mechanism to provide load support. Simulation results provide a biomechanical framework to
identify the muscles and joints, which are critically subjected to musculoskeletal injuries during the activity
under investigation. Analysis of the muscle activation patterns and their distribution of the mechanical
powers revealed the important role of the plantar
exors of the ankle and the extensors of the knee and
hip joints in supporting the body during backpack load carrying.