The metabolic cost of walking is due to muscle force generated to support body weight (BW), external work performed to redirect and accelerate the center of mass (CoM), and internal work performed to swing the limbs and maintain balance. We hypothesized that BW support would incur a greater and lower percentage of Net Metabolic Power (NMP) for uphill and downhill slopes, respectively, compared to level-ground walking. Additionally, we hypothesized that mass redirection would incur a greater and lower percentage of NMP for uphill and downhill slopes, respectively compared to level-ground walking. 10 subjects walked at 1.25 m/s on 0°, ±3°, and ±6° slopes with reduced/added weight and added mass while we measured metabolic rates. We calculated NMP per Newton of reduced BW at each slope and found that BW support required 58% and 64% of the NMP to walk at +3° and +6°, respectively, both greater than the 15% required for level-ground walking (p < 0.025). We calculated NMP per kg of added mass at each slope and found that mass redirection required 19% and 23% of the NMP to walk at +3° and +6°, respectively, both lower than the 35% required for level-ground walking (p < 0.025). We found no significant differences in the percentage of NMP for BW support or mass redirection during downhill compared to level ground walking (p > 0.05). Our findings elucidate that the percentage of NMP attributed to BW support and mass redirection is different for sloped compared to level-ground walking. These results inform biomimetic assistive device designs aimed at reducing metabolic cost.

中文翻译：

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在上坡和下坡上行走时，支撑体重和加速体重变化所需的代谢能力。

步行的代谢成本是由于产生的肌肉力量来支持体重（BW），进行外部工作以重定向和加速质心（CoM）以及进行内部工作以摆动四肢并保持平衡。我们假设，与平地行走相比，BW支撑将分别导致上坡和下坡的净新陈代谢功率（NMP）百分比升高和降低。此外，我们假设，与水平地面行走相比，上坡和下坡斜坡的质量重定向会分别导致NMP的百分比增加和降低。10位受试者以1.25 m / s的速度在0°，±3°和±6°的斜坡上行走，体重减轻/增加，体重增加，同时我们测量了代谢率。我们计算了每个坡度上每牛顿减小的体重的NMP，发现BW支撑分别需要NMP的58％和64％才能在+ 3°和+ 6°处行走，两者都比水平地面行走所需的15％大。 （p <0.025）。我们计算了每个坡度上每千克增加的质量所产生的NMP，发现质量重定向需要分别在19°％和23％的NMP处在+ 3°和+ 6°处行走，均低于35％的水平地面行走（p <0.025）。与平地行走相比，我们发现在下坡期间用于BW支撑或质量重定向的NMP百分比没有显着差异（p> 0.05）。我们的研究结果表明，与水平地面行走相比，对于斜坡而言，归因于BW支持和质量重定向的NMP百分比不同。