Reduced prosthetic stiffness lowers the metabolic cost of running for athletes with bilateral transtibial amputations
Reduced prosthetic stiffness lowers the metabolic cost of running for athletes with bilateral transtibial amputations
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DOI：
10.1152/japplphysiol.00587.2016
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发表时间：
2017-04-01
影响因子：
3.3
通讯作者：
Grabowski, Alena M.
中科院分区：
文献类型：
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作者：
Beck, Owen N.;Taboga, Paolo;Grabowski, Alena M.
受生物腿的弹簧作用的启发，跑步专用假肢旨在使下肢截肢的运动员能够跑步。然而，制造商对假肢刚度和高度的建议可能不会优化跑步性能。因此，我们研究了使用不同的假肢配置的代谢成本和跑步的生物力学的影响。5名双侧经胫骨截肢的运动员在测力跑步机上以2.5或3.0 m/s的速度进行了15次试验。运动员使用3种不同的假肢型号（Freedom Innovations Catapult FX 6、Ossur Flex-Run和Ottobock 1 E90 Sprinter）中的每一种，使用5种刚度类别（制造商推荐的和+/- 1）和高度（国际残奥会最大比赛高度和+/- 2 cm）组合跑步，同时我们测量代谢率和地面反作用力。总的来说，假体刚度[固定效应（β）= 0.036; P = 0.008]而不是身高（P >= 0.089）影响运输的净代谢成本;刚度较小的假体降低了代谢成本。在控制假体刚度（单位：千牛顿/米）的同时，与使用Catapult假体相比，使用Flex-Run（beta = -0.139; P = 0.044）和1 E90 Sprinter假体（beta = -0.176; P = 0.009）可使净代谢成本降低4.3-4.9%。当运动员使用假肢配置降低峰值水平制动地面反作用力（β = 2.786; P = 0.001）、步频（β = 0.911; P < 0.001）和腿部刚度值（β = 0.053; P = 0.009）时，跑步的代谢成本得到改善。值得注意的是，运动员在假肢僵硬的情况下并没有保持腿部的整体僵硬。相反，串联假体刚度支配整体腿部刚度。双侧transtibial截肢运动员的代谢成本运行的影响假体模型和刚度，但不是height.NEW & NOTEWORTHY我们测量了代谢率和生物力学的5名运动员与双侧transtibial截肢，而运行不同的假体配置。通过使用最佳假肢模型和降低假肢刚度，这些运动员跑步的代谢成本最小化。跑步的代谢成本与假肢的高度无关，这表明腿长对长跑不利。此外，串联假肢刚度决定了双侧截肢运动员的腿部刚度。
Inspired by the springlike action of biological legs, running-specific prostheses are designed to enable athletes with lower-limb amputations to run. However, manufacturer's recommendations for prosthetic stiffness and height may not optimize running performance. Therefore, we investigated the effects of using different prosthetic configurations on the metabolic cost and biomechanics of running. Five athletes with bilateral transtibial amputations each performed 15 trials on a force-measuring treadmill at 2.5 or 3.0 m/s. Athletes ran using each of 3 different prosthetic models (Freedom Innovations Catapult FX6, Ossur Flex-Run, and Ottobock 1E90 Sprinter) with 5 combinations of stiffness categories (manufacturer's recommended and +/- 1) and heights (International Paralympic Committee's maximum competition height and +/- 2 cm) while we measured metabolic rates and ground reaction forces. Overall, prosthetic stiffness [fixed effect (beta) = 0.036; P = 0.008] but not height (P >= 0.089) affected the net metabolic cost of transport; less stiff prostheses reduced metabolic cost. While controlling for prosthetic stiffness (in kilonewtons per meter), using the Flex-Run (beta = -0.139; P = 0.044) and 1E90 Sprinter prostheses (beta = -0.176; P = 0.009) reduced net metabolic costs by 4.3-4.9% compared with using the Catapult prostheses. The metabolic cost of running improved when athletes used prosthetic configurations that decreased peak horizontal braking ground reaction forces (beta = 2.786; P = 0.001), stride frequencies (beta = 0.911; P < 0.001), and leg stiffness values (beta = 0.053; P = 0.009). Remarkably, athletes did not maintain overall leg stiffness across prosthetic stiffness conditions. Rather, the in-series prosthetic stiffness governed overall leg stiffness. The metabolic cost of running in athletes with bilateral transtibial amputations is influenced by prosthetic model and stiffness but not height.NEW & NOTEWORTHY We measured the metabolic rates and biomechanics of five athletes with bilateral transtibial amputations while running with different prosthetic configurations. The metabolic cost of running for these athletes is minimized by using an optimal prosthetic model and reducing prosthetic stiffness. The metabolic cost of running was independent of prosthetic height, suggesting that longer legs are not advantageous for distance running. Moreover, the in-series prosthetic stiffness governs the leg stiffness of athletes with bilateral leg amputations.