Determining the impact of lifestyle-related biomechanics on muscle in the ageing human arm

项目摘要（最多4000个字符，包括空格/回车）-来自原始提案摘要：人类正常衰老的特征是肌肉质量和力量减少，导致肌肉骨骼系统功能能力下降。然而，肌肉老化的特征是更复杂的变化，而不仅仅是质量或纤维数量的减少。例如，衰老改变了肌肉纤维的空间排列，包括肌肉厚度、羽状角和平均肌束长度。然而，试图跟踪这种变化的研究偏向于下肢（腿部）肌肉，并且几乎普遍使用极少量的测量来测量每块肌肉的总体结构特性。最近应用高分辨率成像和自动图像分析来测量人类腿部肌肉中的大量纤维（>3000），不仅证明了这种方法的潜在不准确性，而且还强调了重要的功能特征，某些肌肉中纤维结构的高度不均匀性，在这个项目中，我们将使用最先进的医学成像，图像分析和实验生物力学方法。我们将使用MRI扫描和确定性纤维束成像来量化两个具有高度不同的前臂使用的队列（办公室工作人员与体力劳动者）中与年龄相关的肌肉结构变化。相同的受试者还将接受一系列与前臂肌肉力量和运动精度相关的功能测量，从而将肌肉结构的相似性和差异与肌肉骨骼性能的测量相关联。至关重要的是，我们的分析将超越建筑解剖学和肌肉力量之间的“一阶”关系;基于我们最近对下肢肌肉结构的分析，我们将测试新的假设，即纤维结构的不均匀性对前臂和手部的正常肌肉功能至关重要，因此将在两个组群中差异表达，导致在整个生命过程中纤维结构和功能性能的不同轨迹。最后，我们将与工业CASE合作伙伴合作，应用前臂和手部肌肉功能的新知识，使用监督团队开发的双平面X射线摄像和尸体前臂-手部运动模拟器来评估医疗植入物的性能和设计。因此，我们的基础科学将提供有关生活方式如何影响（并可能用于缓解）人类手臂衰老的新数据，并为新医疗技术的发展提供信息。

Project summary (maximum of 4000 characters including spaces/returns) -from original proposal Summary: Normal ageing in humans is characterised by a reduction in muscle mass and strength, which results in reduced functional capacity in the musculoskeletal system. However, muscle ageing is characterised by more complex changes than simply a reduction in mass or fibre number. For example, ageing alters the spatial arrangement of muscle fibres, including muscle thickness, pennation angle and average muscle fascicle length. However, studies that have sought to track such changes have been biased towards lower limb (leg) muscles and have almost universally used an extremely small number of measurements per muscle to characterise their gross architectural properties. Recent application of high-resolution imaging and automated image analysis to measure a large number of fibres (>3000) in human leg muscles have not only demonstrated the potential inaccuracy of such approaches but also highlighted that important functional features, such high levels of inhomogeneity in fibre architecture in certain muscles, may have been missed from such analyses.In this project we will determine the long-term impacts of habitual arm use on age-related changes in muscle architecture and function using a combination state-of-the-art medical imaging, image analysis and experimental biomechanical approaches. We will use MRI scanning and deterministic fibre tractography to quantify age-related variation in muscle architecture in two cohorts with highly disparate forearm-hand use (office workers versus manual workers). The same subjects will also undergo a range of functional measurements related to forearm-hand muscle strength and movement precision, allowing similarities and differences in muscle architecture to be correlated with measures of musculoskeletal performance. Crucially, our analyses will go beyond 'first-order' relationships between architectural anatomy and muscle strength; based on our recent analyses of muscle architecture in the lower limb, we will test the novel hypotheses that inhomogeneity in fibre architecture is crucial to normal muscle function in the forearm and hand, and thus will be differentially expressed in the two cohorts leading to disparate trajectories in fibre architecture and functional performance over the life course. Finally, we will work with an industrial CASE partner to apply this new knowledge of forearm and hand muscle function to evaluate the performance and design of a medical implant using biplanar x-ray videography and a cadaveric forearm-hand motion simulator developed by the supervisory team. Thus, our basic science will provide new data on how lifestyle impacts (and might be used to mitigate) ageing in the human arm, as well as informing the development of new healthcare technologies.