Systematic variation of prosthetic foot spring affects center-of-mass mechanics and metabolic cost during walking.
Systematic variation of prosthetic foot spring affects center-of-mass mechanics and metabolic cost during walking.
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DOI：
10.1109/tnsre.2011.2159018
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发表时间：
2011-08
期刊：
影响因子：
--
通讯作者：
Kuo AD
中科院分区：
文献类型：
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作者：
Zelik KE;Collins SH;Adamczyk PG;Segal AD;Klute GK;Morgenroth DC;Hahn ME;Orendurff MS;Czerniecki JM;Kuo AD
下肢截肢者比非截肢者行走时消耗更多的能量，并且发生继发性残疾的风险更高。假足推出不足可能是一个影响因素。我们的目的是系统地研究假足力学对步态的影响，以深入了解基本的假肢设计原理。我们单独改变了一个参数，即原型假脚中的储能弹簧，即受控能量存储和返回（CESR）脚，并观察了对步态的影响。受试者用带有三种不同弹簧的 CESR 脚行走。我们对截肢者和佩戴假肢模拟器的非截肢者进行了平行研究。在两组中，弹簧特性同样影响脚踝和身体质心 (COM) 力学和代谢成本。较软的弹簧可实现更大的能量存储、能量返回和假肢 COM 推出工作。但中等刚度弹簧的代谢能量消耗最低，这表明尽管推力更大，但最软的弹簧在生物力学上存在缺陷。最软弹簧的缺点可能包括脚跟位移过大和 COM 碰撞损失。我们还观察到截肢者和非截肢者在原型脚上行走时关节动力学存在一些差异。在假肢推出过程中，截肢者表现出从假肢到 COM 的能量传递减少，同时髋部工作增加，这可能是由于膝盖处的能量耗散更大。然而，结果表明，弹簧顺应性有助于推动，但生物力学的权衡限制了更大的推动可能改善步行经济性的程度。
Lower-limb amputees expend more energy to walk than non-amputees and have an elevated risk of secondary disabilities. Insufficient push-off by the prosthetic foot may be a contributing factor. We aimed to systematically study the effect of prosthetic foot mechanics on gait, to gain insight into fundamental prosthetic design principles. We varied a single parameter in isolation, the energy-storing spring in a prototype prosthetic foot, the Controlled Energy Storage and Return (CESR) foot, and observed the effect on gait. Subjects walked on the CESR foot with three different springs. We performed parallel studies on amputees and on non-amputees wearing prosthetic simulators. In both groups, spring characteristics similarly affected ankle and body center-of-mass (COM) mechanics and metabolic cost. Softer springs led to greater energy storage, energy return and prosthetic limb COM push-off work. But metabolic energy expenditure was lowest with a spring of intermediate stiffness, suggesting biomechanical disadvantages to the softest spring despite its greater push-off. Disadvantages of the softest spring may include excessive heel displacements and COM collision losses. We also observed some differences in joint kinetics between amputees and non-amputees walking on the prototype foot. During prosthetic push-off, amputees exhibited reduced energy transfer from the prosthesis to the COM along with increased hip work, perhaps due to greater energy dissipation at the knee. Nevertheless, the results indicate that spring compliance can contribute to push-off, but with biomechanical trade-offs that limit the degree to which greater push-off might improve walking economy.