Functional effects of active muscle stiffness on movement in the elderly

在老年，人们通常难以进行日常活动，例如从椅子上站起来。这种下降的原因还不完全清楚。虽然人们随着年龄的增长而失去力量，但这并不能完全解释他们的问题。研究表明，老年人在支撑身体对抗重力和开始移动时肌肉会紧张。我们认为这是一个主要的缺陷，使他们僵硬的方式，阻碍全身运动。然而，有一个基本的知识缺乏肌肉刚度的影响，主要是由于在运动过程中测量刚度的技术困难。我们提出的项目将开发和测试一种新的方法，用于测量人们从椅子上站起来时的肌肉刚度，老年人认为这具有挑战性。我们要造一个能稍微推人的装置？的腿，并测量有多少阻力存在。这将使我们能够确定他们身体的何处以及何时在运动中他们是僵硬的。我们也会推人吗？当他们安静地坐着的时候，他们的腿。这将有助于我们了解人们对抗重力的方式是否会导致他们的肌肉僵硬。一旦我们制造并测试了这个设备，我们将进行实验，看看老年人是否真的比年轻人更僵硬，在某种程度上，这是有害的，当他们坐着和站起来时。我们还将研究僵硬的人是否比不那么僵硬的人更难从椅子上站起来。如果他们这样做，这将意味着重要的是要教老年人谁有困难，以使用较少的紧张，因为他们移动。如果我们的假设是真的，未来的研究将使用我们的协议来检查和验证可能的再训练方法。

In old age, people commonly have difficulty making everyday movements, such as standing up from a chair. The reason for this decline is not fully understood. Although people lose strength as they age, this does not fully explain their problem. Research has shown that older adults tense muscles as they support their body against gravity and as they start to move. We suggest this represents a primary deficit that makes them stiffer in a way that hampers whole-body movement. However, there is a basic lack of knowledge about the effects of muscle stiffness that is primarily due to technical difficulties in measuring stiffness during movement. Our proposed project will develop and test a new method for measuring muscle stiffness as people stand up from a chair, which elderly people find challenging. We will build a device that slightly pushes on people?s legs, and measures how much resistance there is present. This will enable us to determine where in their body and when in the movement they are stiff. We will also push on people?s legs while they are sitting quietly. This will help us understand whether the way people support themselves against gravity causes their muscles to be stiff. Once we have built and tested this device, we will perform experiments to see whether older people are indeed stiffer than young people, in a way that is detrimental, when they sit and stand up. We will also examine whether stiff people have more difficulty standing up from a chair than people who are less stiff. If they do, this would mean that it will be important to teach older adults who have difficulties moving to use less tension as they move. If our hypothesis is true, future studies will use our protocol to examine and validate possible retraining methods.