Biomechanics of the threshold of balance recovery

平衡恢复阈值的生物力学

• 批准号: RGPIN-2014-06175
• 负责人: Smeesters, Cecile
• 金额: $ 1.75万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567640
• 关键词: Biomechanics; threshold; balance; recovery

Falls are the leading causes of hospitalizations and permanent disabilities due to unintentional injuries in Canada. However, only recently has a critical mass of studies emerged on balance recovery in response to sufficiently large postural perturbations that avoiding a fall is not always possible. Unfortunately, these studies at the threshold of balance recovery have neglected middle-aged adults and sideways and backward losses of balance. They have also used a variety of postural perturbations which makes comparisons between studies difficult. OVER THE LAST 5 YEARS, we evaluated the decline in balance recovery ability across the whole spectrum of ages from 18 to 85yrs; provided further evidence that the choice of postural perturbation does not affect the threshold of balance recovery; and validated an inverted pendulum on a skid model at the threshold of balance recovery. Indeed, using healthy younger, middle-aged and older adults, we showed that balance recovery ability declines exponentially with age as early as 51, 61 and 70yrs for forward, sideways and backward leans, respectively. Moreover, using healthy younger and older adults, we developed a dimensionless method to compare results from different postural perturbations. In particular, this perturbation threshold line method separates falls from recoveries for lean releases, lean releases with waist pull, waist pulls while walking and surface translations. Finally, we showed that an inverted pendulum on a skid model could be used to theoretically predict if a given postural perturbation will lead to an unavoidable fall or if balance recovery is possible. IN THE NEXT 5 YEARS, I will answer some of the remaining questions regarding the effects of AGE and loss of balance DIRECTION on our dimensionless method to compare postural perturbations, as well as begin to explore the influence of PAIN, a risk factor for falls, on the threshold of balance recovery. OUR 1ST OBJECTIVE is to experimentally determine i) the maximum forward initial lean angles from which healthy YOUNGER, MIDDLE-AGED and OLDER adults can be suddenly released and still recover balance using a single step for 3 backward surface translation velocities, and ii) the maximum backward surface translation velocities from which the same participants can be suddenly pulled and still recover balance using a single step for 3 walking velocities. OUR 2ND OBJECTIVE is to experimentally determine the maximum FORWARD, SIDEWAYS and BACKWARD i) initial lean angles and ii) surface translation velocities from which healthy younger, middle-aged and older adults can be suddenly released or pulled, respectively, and still recover balance using a single step. We will also validate the inverted pendulum on a skid model for all of these combined postural perturbations and loss of balance directions. Finally, OUR 3RD OBJECTIVE is to experimentally i) determine the effect of INDUCED PAIN at 2 different sites on the maximum forward initial lean angles in healthy participants, and ii) evaluate one of the possible neurophysiological mechanisms responsible for this interaction. We will also explore possible intervention methods, if this protocol is deemed safe for individuals with CHRONIC PAIN. My engineering approach, using experiments and theoretical modeling as well as biomechanical and neurophysiological measures, will advance knowledge at the threshold of balance recovery. Long term, this proposal will reduce the need for time consuming and dangerous experiments, could help in designing equipment that detects or even prevents falls, and may even help in fall litigation cases. It could also lead to more efficient intervention programs to prevent that first injurious fall, thereby improving quality of life and functional autonomy.

福尔斯是加拿大因意外伤害住院和永久残疾的主要原因。然而，直到最近才出现了大量关于平衡恢复的研究，以应对足够大的姿势扰动，避免跌倒并不总是可能的。不幸的是，这些研究在平衡恢复的门槛上忽略了中年人和平衡的横向和向后损失。他们还使用了各种姿势扰动，这使得研究之间的比较变得困难。在过去的5年里，我们评估了整个年龄范围内的平衡恢复能力下降，从18岁到85岁;提供了进一步的证据，表明姿势扰动的选择不会影响平衡恢复的阈值;并验证了在平衡恢复阈值的防滑模型倒立摆。事实上，使用健康的年轻人，中年人和老年人，我们发现，平衡恢复能力随着年龄的增长呈指数下降，早在51岁，61岁和70岁，分别为向前，侧向和向后倾斜。此外，使用健康的年轻人和老年人，我们开发了一种无量纲的方法来比较不同的姿势扰动的结果。特别地，该扰动阈值线方法将福尔斯与用于倾斜释放、具有腰部拉动的倾斜释放、行走时的腰部拉动和表面平移的恢复分离。最后，我们表明，一个倒立摆的防滑模型可以用来理论上预测，如果一个给定的姿势扰动将导致不可避免的下降，或者如果平衡恢复是可能的。在接下来的5年里，我将回答一些关于年龄和失去平衡方向对我们比较姿势扰动的无量纲方法的影响的剩余问题，以及开始探索疼痛（福尔斯的一个风险因素）对平衡恢复阈值的影响。我们的第一个目标是通过实验确定i）健康的年轻人、中年人和老年人可以突然释放并仍然使用3个向后表面平移速度的单步恢复平衡的最大向前初始倾斜角度，和ii）相同参与者可以突然被拉动并且仍然使用3次步行的单步恢复平衡的最大向后表面平移速度速度我们的第二个目标是通过实验确定健康的年轻人、中年人和老年人可以分别突然释放或拉动的最大前向、侧向和侧向i）初始倾斜角度和ii）表面平移速度，并且仍然使用单个步骤恢复平衡。我们还将验证倒立摆在所有这些组合的姿势扰动和失去平衡的方向上的滑动模型。最后，我们的第三个目标是通过实验i）确定2个不同部位的诱发疼痛对健康受试者最大前向初始倾斜角度的影响，以及ii）评估导致这种相互作用的可能神经生理学机制之一。我们还将探索可能的干预方法，如果该方案被认为对慢性疼痛患者是安全的。我的工程方法，使用实验和理论建模以及生物力学和神经生理学措施，将在平衡恢复的阈值上推进知识。从长远来看，这一提议将减少耗时和危险实验的需要，有助于设计检测甚至防止福尔斯摔倒的设备，甚至可能有助于摔倒诉讼案件。它还可能导致更有效的干预计划，以防止第一次伤害性跌倒，从而提高生活质量和功能自主性。