Mechanisms altering skeletal muscle activation patterns during dynamic tasks

因为我们的躯干占我们整体体重的68%，所以研究我们如何控制躯干的姿势和运动是很重要的。我们必须能够控制躯干的位置，以完成许多日常生活活动，如走路，坐着，举起物体到高性能的运动技能。躯干肌肉也通过产生稳定力来保护脊柱不受过度运动的影响。许多肌肉和关节都参与其中，所以我的研究着眼于关节、骨骼和肌肉的变化如何改变这个复杂的系统如何共同工作，以保持脊柱的稳定性和控制躯干的运动。中枢神经系统控制肌肉如何协同工作。当关节结构或周围肌肉发生变化时（例如，关节松弛度增加，肌肉力量下降），神经系统可以适应改变肌肉的工作方式。利用大量肌肉的表面肌电图（EMG），我想了解神经系统如何适应关节结构的特定变化，这些变化改变了肌肉的协同工作方式。我们的关节、骨骼和肌肉会随着年龄、病理以及男女之间的差异而自然发生变化。研究这些群体提供了一个自然的实验模型来观察这些结构的变化是如何被神经控制系统补偿的。我已经展示了在某些情况下，肌肉是如何通过增加工作强度来做出反应的。然而，在其他情况下，我已经表明肌肉并不以典型的方式协同工作。我想了解为什么会发生这种情况，并找出我是否可以将关节，骨骼和肌肉的特定变化与肌肉如何工作的特定变化联系起来。我们将研究一大群人，他们的年龄范围很广（20-80岁），同时进行标准动作。将采取一系列措施来帮助确定哪些因素对肌肉如何协同工作以移动和保护脊柱的变化最重要。第二个问题是确定我们是否可以将肌肉如何工作的特定模式与控制运动的大脑部分的特定活动模式联系起来。我们将结合躯干肌肉（EMG）和大脑（脑电图）的激活测量来确定这些联系。最后我想了解这些躯干肌肉反应的变化对施加在关节上的力有什么影响。为了做到这一点，我们将通过使用年龄、性别和病理特异性信息来推进目前估计这些力量的方法。目前，这些模型中使用的信息来自健康的年轻人，主要是男性，这并不能很好地估计整个生命周期。这将告诉我们肌肉改变对关节的影响是积极的还是消极的。长期目标是提高对控制躯干功能的重要因素的认识，并开发工具，这些工具将影响与人类运动性能相关的广泛领域的研究和技术（例如工作场所，日常生活活动，高性能运动，临床环境和机器人技术）。例如，考虑到我们的劳动力老龄化，能够理解工作空间设计的限制和潜在变化将是有帮助的，因为许多任务都是在坐着和站着的位置上完成的。此外，许多领域的流行杂志都在谈论“核心”稳定性，但几乎没有科学证据支持许多说法，这项研究的结果将提供信息，可能会导致身体和精神方面的控制训练。最后，控制主干位置的能力是必要的，以执行许多任务在不稳定的表面，如军事和海上工人。

Because our trunk makes up 68% of our overall body mass, it is important to study how we control trunk posture and motion. We must be able to control trunk position to perform many activities of daily living such as walking, sitting, and lifting objects to high performance athletic skills. Trunk muscles also protect the spine from excessive motion by producing stabilizing forces. Numerous muscles and joints are involved so my research looks at how changes in joints, bones and muscles alter how this complex system works together to maintain spine stability and control trunk motion. The central nervous system controls how the muscles work together. When there are changes in joint structures or surrounding muscles (e.g. increased joint laxity, decreased muscle strength) then the nervous system can adapt to change how muscles work. Using surface electromyography (EMG)) from a large number of muscles I want to understand how the nervous system adapts to specific changes in joint structures that alter how the muscles work together. We have naturally occurring changes in the body to joints, bones and muscles with age, pathology, and differences between men and women. Studying these populations provides a natural experimental model to look at how changes in these structures are compensated for by the neural control system. I have shown how the muscles respond in some cases by increasing how hard they work. In other cases, however, I have shown that the muscles do not work together in a typical manner. I want to understand why this happens, and find out whether I can relate specific changes in the joint, bones and muscles to specific changes in how the muscles work. We will study a large group of people across a wide age range (20-80 years) while they perform standard movements. A number of measures will be taken that help determine which factors are most important to the changes in how the muscle work together to move and protect the spine. The second question is to determine whether we can link the specific patterns of how the muscles work with specific patterns of activity in the part of the brain that controls movement. We will combine activation measures from the trunk muscles (EMG) and from the brain (electroencephalography) to determine these links. Finally I want to understand what effect these changes in trunk muscle responses have on the forces that are applied to the joint. To do this we will advance present methods of estimating these forces by using age, sex and pathology-specific information. At present the information used in these models are from young healthy, primarily men which does not give us a good estimate across the life span. This will inform us of whether the muscle alterations have a positive or negative impact on the joint. The long-term goal is to advance knowledge of the factors important to control trunk function and develop tools that will impact research and technology in broad areas related to human movement performance (e.g. work place, activities of daily living, high performance athletics, clinical settings and robotics). For example, given our aging workforce, being able to understand limits and potential changes to work space design would be helpful as many tasks are performed in seated and standing positions. As well popular magazines across a wide range of areas talk about "core" stability but there is really little scientific evidence to back many claims and the results of this study will provide information which may lead to training both physical and mental aspects of control. Finally the ability to control trunk position is necessary to perform many tasks on unstable surfaces such as the military and offshore workers.