|Shawn O’Connor, PhD
Postdoctoral Fellow, Biomedical Physiology & Kinesiology
Lab: K8501 Shrum Science Centre
I am a Postdoctoral Fellow in Biomedical Physiology & Kinesiology at Simon Fraser University in Vancouver, British Columbia. In 2009, I completed my PhD in Biomedical Engineering at the University of Michigan with Dr. Art Kuo as my primary supervisor. I also received my MS in Biomedical Engineering from the University of Michigan in 2006, and my BS in Mechanical Engineering from the Georgia Institute of Technology in 2004, which included a four-semester internship at Motorola. My doctorate research focused on a) designing computer-based biomechanics simulations to study the importance of dynamics and elastic limb behavior during gait and b) testing the visual control of walking balance. During my postdoc, I have developed a treadmill based virtual reality system and determined how vision is used to predict and optimize walking speed. I am also building a respiratory gas control system for manipulating perceptions of metabolic cost and studying how humans optimize gait patterns.
- Compliance in Legged Locomotion
I have developed a passive locomotion model with compliant legs that produces a variety of gait behaviors such as walking, skipping, and running by only varying a small number of parameters. In each of these gaits, the compliant behavior models the action of muscle and tendon and can predict the energetic cost of these movements. These findings provide insight on how humans tune their bodies to save energy and change gaits, and on how robots could be designed to locomote more economically.
- Gait Adaptations and Energy Optimization
How do humans optimize energetic cost? For decades we have known that humans and other animals preferentially select economical gait patterns but the mechanisms responsible for this behavior have remained a mystery. I have recently demonstrated that vision is used for rapid prediction of energetic cost using virtual reality to invoke false perceptions of speed and while measuring adaptations in preferred walking speed. Please visit this video published by the Journal of Neurophysiology to learn more about our methods and experimental approach. I also explain how the custom virtual reality treadmill was developed in a Matlab Newsletter. I am currently developing an experimental system for directly perturbing sense of metabolic cost by altering the concentrations of oxygen and carbon dioxide in the blood during walking.
- Neuromechanics of Animal Locomotion
I have also worked with Heather More as part of the Danish Cardiovascular Giraffe Research Project, during which I traveled to South Africa to study neural and muscular delays in giraffes.
- Future Work
I will continue to use approaches from mechanical engineering, biomechanics, and neurophysiology to discover clinically relevant principles underlying locomotion. Specifically, I will investigate how the nervous system coordinates with natural dynamics of the limbs and apply this knowledge to develop rehabilitation strategies to improve recovery after neurological injury. To meet this aim, I will develop models of human locomotion, build mechanisms that aid impaired locomotion, and design novel experimental paradigms for testing the control of human locomotion.
1. “Physiological mechanisms underlying prediction and optimization of metabolic cost during walking” Dynamic Walking Conference, May 2012, Pensacola, FL.Watch video.
2. “Simplified models of locomotion: a little does a lot” IRMACS Modeling Consortium, Simon Fraser University, March 2012, Burnaby, BC, Canada. Watch video.
3. O’Connor, S.M., Kuo, A.D. “Direction dependent visual weighting for walking and standing balance” Dynamic Walking Conference, June 2009, Burnaby, BC, Canada. Watch video.
1. O’Connor S.M., Xu, H.Z., Kuo, A.D. (2012) “Energetic cost of walking with increased step variability.” Gait and Posture. 36(1): 102-107.
2. More H.L., O’Connor S.M., Brøndum, E., Wang, T., Bertelsen, M.F., Grøndahl C., Kastberg K., Hørlyck, A., Funder, J., Donelan, J.M. “Sensorimotor responsiveness and resolution in the giraffe.” Journal of Experimental Biology. (accepted pending minor revisions).
3. O’Connor S.M., Donelan, J.M. (2012) “Fast visual prediction and slow optimization of preferred walking speed.” Journal of Neurophysiology. 107(9): 2549-59.
4. O’Connor S.M., Kuo, A.D. (2009). “Direction-dependent control of balance during walking and standing.” Journal of Neurophysiology. 102(3): 1411-9.
5. Ross, J.D., O’Connor, S.M., Blum, R.A., Brown, E.A., DeWeerth, S.P. (2004). ”Multielectrode impedance tuning: reducing noise and improving stimulation efficacy” International Conference of the IEEE Engineering in Medicine and Biology Society, September 2004, San Francisco, CA. Conference Proceedings; Volume 2, 2004 Page(s):4115 - 4117 Vol.6