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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638456
• 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.

在加拿大，跌倒是因意外伤害而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，这些关于平衡恢复阈值的研究忽略了中年人以及侧向和向后平衡丧失。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年中，我们评估了从18岁到85岁的整个年龄谱中平衡恢复能力的下降；提供了进一步的证据，表明姿态扰动的选择不影响平衡恢复的阈值；并在滑移模型上验证了倒立摆的平衡恢复阈值。事实上，在健康的年轻人、中年人和老年人中，我们发现平衡恢复能力随着年龄的增长呈指数级下降，分别早在51岁、61岁和70岁时就开始前倾、侧倾和后倾。此外，使用健康的年轻人和老年人，我们开发了一种无量纲方法来比较不同姿势扰动的结果。特别地，这种摄动阈值线方法将跌倒与瘦释放的恢复、腰部拉扯的瘦释放、行走时腰部拉扯和表面平移分开。最后，我们证明了一个倒立摆在一个打滑模型上可以用来理论上预测一个给定的姿势扰动是否会导致不可避免的跌倒，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平衡方向丧失对我们的无量纲方法比较姿势扰动的影响的剩余问题，并开始探索疼痛（跌倒的风险因素）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的最大前倾初始角度，并且仍然可以在3个向后表面平移速度的单步中恢复平衡，ii)同样的参与者可以在3个步行速度的单步中突然被拉出并恢复平衡的最大向后表面平移速度。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向前，侧向和向后i)初始倾斜角和ii)表面平移速度，并且仍然可以用一步恢复平衡。我们还将在滑移模型上验证倒立摆，以验证所有这些组合的姿势扰动和平衡方向的丧失。最后，我们的第三个目标是通过实验i)确定2个不同部位的诱导性疼痛对健康参与者最大前倾初始角度的影响，ii)评估这种相互作用的可能神经生理机制之一。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，利用实验和理论建模，以及生物力学和神经生理学的措施，将在平衡恢复的门槛上推进知识。从长远来看，这一提议将减少对耗时和危险的实验的需求，有助于设计检测甚至防止跌倒的设备，甚至可能有助于处理跌倒诉讼案件。它还可能导致更有效的干预计划，以防止第一次受伤的跌倒，从而提高生活质量和功能自主权。