It is a research interest in the biomechanical lab of Seoul National University.
Equipment Design for Enhancement of Motor Functions
Our research has focused mainly on basic research to understand the biomechanical and control mechanisms by which human movements are governed. Based on these mechanisms, our broad, long-term research plan is to translate the current research to more applied fields so that research outcomes can help the community through injury prevention, aging process comprehension, motor performance enhancement, and rehabilitation with the help of functional equipment. There is a critical need to better understand the neuromechanical origin of this phenomenon and applications. In the absence of such understanding, the development of treatments and interventions will not be feasible.
Quantification of Synergic Actions in Human Movements
The human body is a complex system of redundant forms in which the degrees-of-freedom (DOFs) of elements is generally larger than the DOFs (i.e., dimensionality) of task space, and this phenomenon has been postulated as the motor redundancy or the DOF problem. The strategies of organizing a family of solutions for successful performance is definitely a process of neural structure in the biological system, and the term, synergy, has been proposed to describe and quantify the process and consequence of neural activities for governing a redundant set of body elements. We have quantified synergic actions of elements at various levels, including motor units, muscles, end-effector forces, etc.
Bridging the Gap between Biomechanics and Motor Control in Human Movements
One of the common goals of the human movement sciences would be to understand the basic mechanisms of coordinated movements. Thus, the interdisciplinary research approach by biomechanical and motor control perspectives is natural and necessary. The human body could be understood by means of mechanical principles, and the movements are governed by a controller, the human brain. All the voluntary movements are a consequence of brain activities, so these two aspects should be considered to have a proper understanding of behavioral outcomes. Biomechancal studies explain how peripheral and biomechanical constraints acting on the human body, and neuroscience and motor control studies describe how neural commands are generated and are transferred to the peripheral system and its changes with aging fatigue training or many other factors. We view the human movement system as a whole rather than just a mechanical aspect, which helps us tremendously understanding the biological system.
Clinical Application of Synergy Quantification
Current researches of the HBL has been expanded to investigate how the CNS optimizes solutions when the peripheral system involves mechanical redundancy, and how motor variability is compatible with optimality in human motor actions. We have expanded this line of research by examining central and peripheral adaptations in human movements to internal (e.g., aging, fatigue, injury, movement disorder, etc) and external changes (e.g., environment-related changes such as zero-gravity environment in space) in optimality and motor variability. Answering this question is critical not only because it has been a century-long question in robotics and human motor control but also because the advent of brain-computer interfaces (BCI) in modern times has made answering this question more imperative. For example, one of the main objectives in BCI is to reduce the amount of redundancy in both the neural and mechanical systems for effective processing of recorded neural signals from the CNS and efficient control of artificial limbs, respectively. Additionally, We are currently conducting several studies on musculoskeletal mechanisms and mathematical modeling of optimization on end-effector forces or muscle activities, as well as their applications for people with movement deficit and disorder such as patients with Parkinson’s disease, cerebellar disorders, stroke, cerebral palsy, essential tremor, etc. In particular, new clinical research suggests that workers exposed to welding fumes and pesticides may be at risk for developing brain damage in an area of the brain affected in Parkinson’s disease. The studies with the cohorts of welders and farmers provide an exciting opportunity for early detection of Parkinson’s disease and for tracking its progression and effects of treatment. They also suggest that the newly invented experimental paradigms may be used in other cases of impaired coordination in neurological patients.