Neuromechanical mechanisms of human dynamic stability

点击翻译按钮获取中文摘要

The high incidence of falls and fall-related injuries among Canadians over the age of 65 is a key public health issue. The most current data indicates that this cohort represents approximately 15% of the Canadian population, yet it accounts for 51% of all unintentional fall cases requiring hospitalisation and totals 46% of health care costs for falls. As a result, the direct and indirect healthcare costs have been estimated at over 2 billion and 6 billion Canadian dollars, respectively. Despite population-based work that has revealed numerous factors that are predictive of falls, there has been little change in the population standardised rate of fall-related hospitalisation and injury among older adults. Effective balance control is the result of a complex relationship between proactive (to avoid instability) and reactive (to respond to instability) control processes that are bound by the neural (sensory) and mechanical (musculoskeletal) systems. Notwithstanding considerable clinical research focusing on balance control and falls among older adults, there is a scarcity of basic science research investigating the mechanisms of whole-body stability control. The proposed work will generate novel insights into human stability control and dyscontrol through three research themes that iteratively narrow in focus, moving from (a) a characterisation of whole body dynamic stability control, to (b) experimental manipulation of neuromechanical system properties, to (c) modelling individual-limb and joint-level contributions to dynamic stability. This work will utilise a combination of complementary biomechanical approaches to examine human dynamic stability across a range of activities of daily living. While many previous studies have examined proactive and reactive stability control in isolation, the present work will seek to examine the interaction between proactive and reactive control to determine if challenges in reactive control can be offset by improved proactive control. Such an outcome would support the use of perturbation-based training programs, which seek to improve proactive control through exposure to novel bouts of instability. This work will also seek to quantify the extent to which instability results from alterations to the neural and mechanical systems, given that these systems are directly influenced by growth, ageing and injury processes. Outcomes from this line of work will importantly inform the development of technological interventions seeking to offset neuromechanical deficits. Lastly, understanding individual limb and joint level contributions to dynamic stability provides a specific target to facilitate the development of more effective medical and technological fall prevention interventions. This line of study provides a framework for the training of nine undergraduate and graduate students within this funding period.