Lower limb prostheses for individuals who carry infants, toddlers, and other loads

项目摘要(公开摘要) 自然的下肢提供重要的生物力学功能，如支持体重、向前 行走过程中的推进和平衡控制。当下肢所承受的负荷发生变化时， 肌肉的激活相应地做出反应，以实现生物力学功能的无缝延续。这些负荷 可能会突然改变，例如在背负婴儿、蹒跚学步的孩子或其他重物时，如沉重的背包。为 对于截肢的人来说，这些负重负荷的突然变化可能是有问题的 因为它们会对行走能力产生负面影响。行走能力可能会下降的一个原因是 大多数假肢的特性，如它们的僵硬，是恒定的，不会改变以适应变化。 加载条件。另一个原因是，最广泛使用的假肢没有马达、传感器、 或者像大脑一样的控制器，用来取代截肢的神经肌肉系统。不管是什么 原因是，没有证据可以指导带假肢和经验的退伍军人的处方实践 负载突然变化。 拟议的研究将使用实验和建模分析来为退伍军人管理局临床医生提供指导 为经常携带婴儿、幼儿或其他肢体截肢的退伍军人开假肢处方 大把的。我们提出的研究有两个具体目标： 具体目标1：确定退伍军人改善行走能力的假足 下肢截肢可负重婴儿、蹒跚学步的儿童或其他重物。我们建议进行一项人体实验 在15名膝盖以下截肢患者的帮助下进行实验。研究参与者将走在 无附加负荷和四种附加负荷情况下的跑步机使用重量包(13.6千克或~30磅) 模仿婴儿、蹒跚学步的孩子或其他负重物品。这四个条件包括绑在他们前面的背包，他们的后面， 并将手臂放在完整的肢体侧和假肢侧。每个参与者都将穿着一件平常的 假肢脚，这只脚有一个脚跟僵硬的楔子，同样的假脚，但只有一类僵硬 更高，一种新上市的双龙骨假肢，用于负重情况，以及一种动力脚踝 假肢。这些实验的结果将帮助退伍军人临床医生指定最佳的假体 经常背负婴儿、蹒跚学步的孩子或其他重物的下肢截肢退伍军人。 具体目标2：确定肌肉对特定生物力学参数的敏感性 对不同的刚度和加载条件的响应。我们建议使用高级建模和 模拟分析以确定足部僵硬如何影响个体肌肉对特定肌肉的贡献 生物力学参数包括体重支持、向前推进、平衡控制、能量 支出，以及目标1中检查的不同加载条件的联合加载。我们将进一步执行 增加重量增量的探索性分析，以发现肌肉贡献对 生物力学量。我们预计这些结果将对这些关系提供重要的洞察力 因为有了我们的模型，我们可以探索比我们用实验更广泛的条件 方法和志愿者。 对于携带婴儿、幼儿或其他负重物品时戴着假肢的退伍军人来说，这项研究将 提供证据支持减少不良代偿反应的假体处方实践 装载马车。我们的目标是帮助临床医生从当前可用的解决方案中进行选择，以使退伍军人能够 来实现他们的生活和工作目标。

PROJECT SUMMARY (PUBLIC ABSTRACT) The natural lower limbs provide important biomechanical functions such as body weight support, forward propulsion, and balance control during ambulation. When the loads borne by the lower limbs change, lower limb muscle activation responds accordingly to enable seamless continuation of biomechanical function. These loads can change suddenly, such as when carrying an infant, toddler, or other load like a heavy backpack. For individuals with a lower limb amputation, these sudden changes to weight-bearing loads can be problematic because they can negatively impact walking performance. One reason walking performance may suffer is that the properties of most prosthetic limbs, such as their stiffness, are constant and do not change to suit varying load conditions. Another reason is that the most widely prescribed prosthetic feet do not have motors, sensors, or brain-like controllers that act to replace the neuromuscular system of the amputated limb. Regardless of the reason, no evidence exists to guide prescription practice for veterans who walk with a prosthesis and experience sudden load changes. The proposed research will use experimental and modeling analyses to create guidance for VA clinicians who prescribe prostheses to veterans with a lower limb amputation who frequently carry infants, toddlers or other loads. Our proposed research has two specific aims: Specific Aim 1: Identify the prosthetic foot that results in improved walking performance when veterans with lower limb amputation carry infants, toddlers, or other loads. We propose to conduct a human subject experiment with help of fifteen individuals with below-knee amputations. Study participants will walk on a treadmill with no added load and four added load conditions using a weighted pack (13.6 kg or ~30 lbs) to simulate an infant, toddler, or other load. The four conditions include the pack strapped to their front, their back, and carried with their arms on the intact limb side and the prosthetic limb side. Each participant will wear a usual prosthetic foot, this same foot with a heel-stiffening wedge, the same prosthetic foot but one category stiffness higher, a new-to-market dual keel prosthetic foot intended for load carrying situations, and a powered ankle foot prosthesis. The results from these experiments will aid VA clinicians in specifying the best prosthesis for veterans with lower limb amputations who frequently carry infants, toddlers, or other loads. Specific Aim 2: Identify the sensitivity of muscle contributions to specific biomechanical quantities in response to the different stiffness and loading conditions. We propose to use advanced modeling and simulation analyses to identify how foot stiffness influences individual muscle contributions to specific biomechanical quantities including body weight support, forward propulsion, balance control, energy expenditure, and joint loading for the different loading conditions examined in Aim 1. We will further perform exploratory analyses with increased weight increments to discover the sensitivity of muscle contributions to the biomechanical quantities. We anticipate these results will provide significant insight into these relationships because with our model we can explore a much wider range of conditions than we can using experimental methods and volunteer participants. For veterans who wear a lower limb prosthesis while carrying infants, toddlers, or other loads, this research will provide evidence to support prosthesis prescription practice that reduces undesirable compensatory responses to load carriage. Our objective is to help clinicians select among currently available solutions to enable veterans to achieve their life and work goals.