Rules to limp by: principles of gait compensation from animal and human studies of legged locomotion

Date(s) - 01/27/2014
4:00 pm

Young-Hui Chang, PhD, Associate Professor, School of Applied Physiology, Georgia Institute of Technology


Nearly all diseases affecting the neuromusculoskeletal system have the potential to result in some form of locomotor pathology. These gait deficits negatively impact the ability to walk and run effectively and economically, which can have devastating consequences on quality of life of the individual. Although much has been published characterizing features of these deficits, we still lack basic tenets that can form a theoretical framework for how we compensate for gait abnormalities. In our lab, we recently found common locomotor compensation principles that exist across three very different taxonomic groups, from rats to cats to humans. These findings suggest that the mammalian nervous system may utilize and exploit motor equivalence within the legs to coordinate and compensate for disturbances on a step-by-step basis and after neuromuscular injury. We further found these compensatory principles are not intrinsic mechanical properties, but must be learned. And, more importantly for rehabilitation, they can be adapted in accordance with the motor control principle of minimum intervention. We are currently investigating these ‘rules to limp by’ within the context of gait in persons with a unilateral below-knee amputation. We have also found that clinical studies of amputee gait can provide great insights into our fundamental understanding of locomotion and what neuromuscular triggers might determine whether we choose to walk or run at a particular speed. Using a comparative approach, common locomotor principles discovered in nature can inform how we approach clinical rehabilitation research and, in turn, the clinical research can inform and improve our basic understanding of the natural system.

Short Bio:

Dr. Chang is an Associate professor of Applied Physiology at the Georgia Institute of Technology with appointments in the Georgia Tech Bioengineering program and the Emory-Georgia Tech joint Biomedical Engineering program. Young-Hui (pronounced “younghee”) earned his BS in Mechanical Engineering from Cornell University, MS in Animal Physiology from the Cornell University College of Veterinary Medicine, and his PhD in Integrative Biology from the University of California, Berkeley. He spent three years as an NIH postdoctoral fellow at the Emory University School of Medicine before joining the faculty at Georgia Tech in 2004. His primary research interests are related to understanding “how we get from here to there.” In particular, he employs a comparative approach to discern broad locomotion principles that apply across many different species. His work aims to improve our basic understanding of how legs are used to walk and run and how this knowledge may be applied to gait rehabilitation medicine. Dr. Chang, is the recipient of the NSF CAREER Award and has had some of his work with NSF highlighted by the director of the NSF before the U.S. National Science Board. His research is currently supported by the NSF, the National Institute of Neurological Disorders and Stroke (NINDS), and CSX Corporation.