Grant: Research Tools and Instruments - Category 1 (<$150,000)

A surgeon has a new idea for a procedure that may help an injured patient walk again.  The procedure involves shifting the bone attachment points for some tendons and ligaments.  But how does the surgeon test out their idea before using it on a patient?  How can a biomechanical engineer design and test a new prosthesis or rehabilitation device?  The safety implications are enormous.  Predictive computer simulations can help answer these and other questions, but the simulations must give accurate results. The aim of our research is to develop reliable simulations of biomechanical systems, with primary application to human walking. The applicants will build upon previous research in multibody dynamics, in which algorithms have been developed to automatically simulate the motion of a system of interconnected bodies.  However, recent attempts to extend multibody dynamics to the analysis of human motions have encountered a number of challenges:  the nonlinearity of muscles, ligaments, and other soft tissues, especially during contact with the ground or other hard surfaces, and the modelling of the human control system that guides our actions. We have now developed controllers that mimic the central nervous system during walking; these controllers maintain balance while minimizing the metabolic energy consumption, just as a human does.  We are currently developing new models for contact forces between soft human tissue and the ground.  Before these contact models can be included in a predictive computer simulation though, they must be tested and validated. The equipment requested will provide the vertical and lateral force measurements that we need to validate the ground reaction forces predicted by our contact models. With validated models, we can create forward dynamic simulations that will predict the effects of surgical interventions or assistive devices.  The requested equipment will also facilitate inverse dynamic analyses, in which the measured forces and motions are used to determine muscle and joint loading.  Our long-term research goal is to work with health care professionals to apply our simulation tools to the treatment of illnesses and the design of assistive devices.