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

项目概要（公开摘要） 自然下肢提供重要的生物力学功能，例如体重支撑、向前移动、运动和运动。 推进和平衡控制。当下肢承受的载荷发生变化时， 肌肉激活相应地作出响应以使得生物力学功能能够无缝地延续。这些载荷 可以突然改变，例如当携带婴儿，幼儿或其他负载，如沉重的背包。为 对于下肢截肢的人来说，这些承重负荷的突然变化可能是有问题的 因为它们会对行走性能产生负面影响。行走性能可能受到影响的一个原因是， 大多数假肢的特性，例如它们的刚度，是恒定的，不会改变以适应变化的 负载条件另一个原因是，最广泛使用的假肢脚没有电机，传感器， 或者类似大脑的控制器，用来取代截肢的神经肌肉系统。无论 原因，没有证据可以指导使用假肢行走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，为VA临床医生提供指导， 为下肢截肢的退伍军人开假肢，他们经常携带婴儿，幼儿或其他 载荷我们提出的研究有两个具体目标： 具体目标1：确定假肢脚，导致改善行走性能时，退伍军人 下肢截肢的人携带婴儿、幼儿或其他负载。我们建议进行一项人体实验 在15名膝下截肢者的帮助下进行实验。研究参与者将在一个 跑步机，无附加负荷和四种附加负荷条件，使用负重包（13.6 kg或~30 lbs）， 模拟婴儿、幼儿或其它负载。这四个条件包括背包绑在他们的前面，他们的后面， 并将手臂放在完好肢体侧和假肢侧。每个参与者将穿着一个通常的 假肢脚，同样的脚，有一个脚跟加强楔，同样的假肢脚，但一类刚度 更高，一个新的市场双龙骨假肢脚旨在负荷情况下，和一个动力踝足 假肢这些实验的结果将有助于VA临床医生指定最佳假体， 下肢截肢的退伍军人，他们经常携带婴儿，幼儿或其他负载。 具体目标2：确定肌肉贡献对特定生物力学量的敏感性， 不同刚度和载荷条件下的响应。我们建议使用先进的建模和 模拟分析，以确定足部刚度如何影响个体肌肉对特定 生物力学量，包括体重支撑、向前推进、平衡控制、能量 支出，并在目标1中检查的不同加载条件下的联合加载。我们将进一步执行 探索性分析，增加体重增量，以发现肌肉对 生物力学量我们预计这些结果将为这些关系提供重要的见解 因为通过我们的模型，我们可以探索比实验更广泛的条件， 方法和志愿者参与者。 对于那些在携带婴儿、幼儿或其他负荷时佩戴下肢假肢的退伍军人，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 装载运输。我们的目标是帮助临床医生选择目前可用的解决方案，使退伍军人 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.