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Degree

Doctor of Philosophy, Case Western Reserve University, Biomedical Engineering, 2004.

Abstract

The impact of passive elastic and viscous joint properties during functional electrical stimulation (FES) standing was investigated with a musculoskeletal model of the human body adapted for spinal cord injury (SCI). Initially passive joint properties were measured from individuals with and without SCI to determine whether any differences existed. Then a mathematical model was developed to describe the passive joint moments and was integrated into the musculoskeletal model. Static computer simulations were performed with the musculoskeletal model to determine the impact that passive joint property changes had on the muscle effort required to stand. Dynamic computer simulations were also performed to understand the impact that passive property changes had on postural stability during a disturbance. The passive moment measurements showed that the passive moments at every joint except the knee were significantly higher in the subjects with SCI. The 11 static simulation results revealed that an increase in joint stiffness can increase or decrease the required energy during stance depending upon the location of the center of mass (COM) within the workspace. From the dynamic simulations, it was concluded that increases in joint stiffness and viscosity do aid individuals in their ability to resist external disturbances. Through this better understanding of passive properties, methods to exploit them to reduce muscle effort and increase stability can be found and improved musculoskeletal models can be built to develop improved FES control systems.

Keywords

Passive Properties; Stiffness; Viscosity; Musculoskeletal modeling; Nonlinear modeling; Spinal cord injury; Biomechanics; Computer simulation

Advisor

Ronald J Triolo

Pages

108p.

Document number: case1081532731
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=case1081532731

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