Computational model to investigate upper limb biomechanics

骨骼、肌肉和其他组织之间的机械相互作用是控制肌肉骨骼系统维护的关键刺激。为了了解这些系统是如何正常工作的，重要的是要确定其潜在的生物力学特性。不幸的是，活体肌肉骨骼系统中的结构所感受到的力是极其难以直接测量的。作为对这一问题的解决方案，计算模型已经成为估计人类和动物肌肉产生的和骨骼和关节经历的负荷的重要工具。到目前为止，大多数人类肌肉骨骼模型的研究和开发都集中在腿部模型上。模拟上肢力学的计算模型不太常见，主要是因为一些关节的复杂性增加，与下肢相比，可能的运动范围更广。目前的上肢模型往往被设计成专注于特定的任务(如举起和伸展的人体工学)或特定的关节，最常见的是肩关节复合体。仍然需要能够用于更广泛种类的任务和加载事件的动态模拟的更通用的上肢模型。具体地说，上肢肌肉力量模式的特征可以用来进一步了解手臂和手腕中的骨骼是如何加载的。在观察骨骼强度时，这一点尤其重要，因为骨骼适应其负载环境，并且施加到上肢骨骼的大部分力来自肌肉。这在了解骨骼健康发育的机制、矫形设计(如支具)和开发太空飞行的骨丢失对策方面有直接的应用。我的研究计划的长期目标是开发一个全面的动态上肢肌肉骨骼模型，该模型可以用于研究各种人类活动中肌肉力量的产生以及相应的骨骼和关节负荷。我的研究小组已经开发并验证了一个动态的双侧上肢模型，能够模拟各种负荷活动。在现有工作的基础上，拟议的NSERC Discovery Grant试图在三个方面扩展和改进我们当前的模型：1)实施和验证肌电辅助模拟，以改进等长和动态任务中的肌力估计。2)为手实施接触机制，以实现动态冲击加载模拟。3)使用特定于对象的校准来实现改进的联合表示，并实现更逼真的手模型。这项探索基金的研究将满足对一个全面的动态上肢肌肉骨骼模型的需求，并推动工具的开发，从而进一步了解手臂中的骨骼和关节负荷。

Mechanical interactions between bones, muscles and other tissues are critical stimuli that govern maintenance of musculoskeletal systems. In order to understand how these systems function normally, it is important to characterize their underlying biomechanics. Unfortunately, forces experienced by structures within a living musculoskeletal system are extremely difficult to measure directly. As a solution to this, computational models have become an important tool for estimating loads generated by muscles and experienced by bones and joints in humans and animals. Most human musculoskeletal modelling research and development to date has been focused on lower limb models. Computational models that simulate upper limb mechanics are less common primarily due to increased complexity of some of the joints and the wider range of possible movements when compared to lower limbs. Current upper limb models tend to be designed to focus on specific tasks (such as ergonomics of lifting and reaching) or on specific joints, most commonly the shoulder joint complex. There is still a need for more general upper limb models that can be used in dynamic simulations of a wider variety of tasks and loading events. Specifically, characterization of muscle force patterns in the upper limb can be used to further understanding of how bones in the arm and wrist are loaded. This is particularly important when looking at bone strength as bones adapt to their loading environment and the majority of forces applied to upper limb bones comes from muscles. This has direct applications in understanding the mechanisms of healthy bone development, in orthopaedic design (e.g. braces) and for developing bone-loss countermeasures for space flight. The long-term goal of my research program is to develop a comprehensive dynamic upper limb musculoskeletal model which can be used to investigate muscle force generation and the corresponding bone and joint loading in a wide variety of human activities. My research group has developed and validated a dynamic bilateral upper limb model capable of simulating a variety of loaded activities. Building on this existing work, the proposed NSERC Discovery Grant seeks to extend and refine our current model in three areas: 1) Implement and validate electromyography assisted simulations to improve muscle force estimation for both isometric and dynamic tasks. 2) Implement contact mechanics for the hand to enable dynamic impact loading simulations. 3) Implement improved joint representations with subject-specific calibration and implement a more realistic hand model. This Discovery Grant research will address a need for a comprehensive dynamic upper limb musculoskeletal model and advance the development of tools that provide further understanding of bone and joint loading in the arm.