Independent metabolic costs of supporting body weight and accelerating body mass during walking
Independent metabolic costs of supporting body weight and accelerating body mass during walking
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DOI：
10.1152/japplphysiol.00734.2004
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发表时间：
2005-02-01
影响因子：
3.3
通讯作者：
Kram, R
中科院分区：
文献类型：
--
作者：
Grabowski, A;Farley, CT;Kram, R
步行的代谢成本由许多机械任务决定，但每项任务的个体贡献仍不清楚。我们假设，在正常行走过程中，支撑体重所产生的力以及重定向和加速体重所进行的工作都会产生显着的代谢成本。为了检验我们的假设，我们测量了代谢率的变化，以响应模拟的重力减小和负载增加的组合。我们发现，通过模拟重力减轻来减轻体重会适度降低净代谢率。通过计算减轻体重每牛顿的代谢成本，我们推断产生支撑体重的力约占正常行走代谢成本的 28%。与之前的负荷研究类似，我们发现增加体重和质量会增加净代谢率，且与负荷成正比。然而，当我们通过模拟降低重力和增加负荷的组合来单独增加质量时，净代谢率比我们同时增加重量和质量时增加了约一半。通过计算每增加一公斤质量的成本，我们推断出质心所做的功相当于正常行走代谢成本的 45%。我们的研究结果支持这样的假设：力量和工作都会产生显着的代谢成本。具体来说，执行重定向和加速质心的工作的成本几乎是产生支撑体重的力的成本的两倍。
The metabolic cost of walking is determined by many mechanical tasks, but the individual contribution of each task remains unclear. We hypothesized that the force generated to support body weight and the work performed to redirect and accelerate body mass each individually incur a significant metabolic cost during normal walking. To test our hypothesis, we measured changes in metabolic rate in response to combinations of simulated reduced gravity and added loading. We found that reducing body weight by simulating reduced gravity modestly decreased net metabolic rate. By calculating the metabolic cost per Newton of reduced body weight, we deduced that generating force to support body weight comprises similar to28% of the metabolic cost of normal walking. Similar to previous loading studies, we found that adding both weight and mass increased net metabolic rate in more than direct proportion to load. However, when we added mass alone by using a combination of simulated reduced gravity and added load, net metabolic rate increased about one-half as much as when we added both weight and mass. By calculating the cost per kilogram of added mass, we deduced that the work performed on the center of mass comprises similar to45% of the metabolic cost of normal walking. Our findings support the hypothesis that force and work each incur a significant metabolic cost. Specifically, the cost of performing work to redirect and accelerate the center of mass is almost twice as great as the cost of generating force to support body weight.