为什么我们走路时双臂伸直，而跑步时双臂弯曲?

为什么我们走路时双臂伸直，而跑步时双臂弯曲?

Running with your arms bent and walking with your arms straight is what most of us do, but until recently, scientists didn't know why.

大多数人都是弯着胳膊跑步，伸直胳膊走路，但直到最近，科学家们才知道为什么。

To find out, Andrew Yegian and his fellow researchers at Harvard University had eight volunteers walk and run on a treadmill with their arms straight and bent. Six of the participants wore oxygen masks to record how much oxygen they used. Researchers tracked all the volunteers' movements using reflective markers on their shoulders, wrists and elbows, according to The Guardian.

为了找到答案，安德鲁·耶吉安和他在哈佛大学的同事让8名志愿者在跑步机上行走和跑步，他们的手臂伸直或弯曲。六名参与者戴着氧气面罩，记录他们使用了多少氧气。据《卫报》报道，研究人员用志愿者肩膀、手腕和肘部的反光标记跟踪了所有志愿者的运动。

The team predicted that it was more efficient to have straight arms while walking and bent arms while running, but they were only half right.

研究小组预测，走路时伸直胳膊和跑步时弯曲胳膊效率更高，但他们只对了一半。

They found that walking with arms bent used more energy than walking with straight arms, increasing oxygen consumption by 11%. But surprisingly, running with bent arms was no more efficient than running with straight arms.

他们发现弯曲手臂走路比伸直手臂走路消耗更多的能量，增加了11%的耗氧量。但令人惊讶的是，弯曲手臂跑步并不比伸直手臂跑步更有效。

"Pretty much every subject in the study said that straight-arm running was the most challenging condition," Yegian told New Scientist. "That’s why it was very surprising when we couldn’t find any difference in the energetics.”

耶吉安在接受《新科学家》杂志采访时说:“几乎所有参与研究的人都说，伸直手臂跑步是最具挑战性的。”“这就是为什么当我们在能量学上找不到任何不同时，会感到非常惊讶。”

We tend to walk with our arms straight and run with our arms bent. (Photo: maxpro/Shutterstock)

The study, which was published in the Journal of Experimental Biology, involved students who ranged from marathon runners to those who ran just a few times a week.

这项研究发表在《实验生物学杂志》上，研究对象包括从马拉松运动员到每周只跑几次的学生。

The researchers say they don't know why we usually bend our arms when we run. Yegian says he thinks there has to be some beneficial reason. It could be because bending the arms helps stabilize the head.

研究人员表示，他们不知道为什么我们跑步时通常会弯曲手臂。耶吉安说，他认为肯定有一些有益的原因。这可能是因为弯曲手臂有助于稳定头部。

And because the research was only conducted at low running speeds, the benefit of arm bending may be more obvious at higher speeds.

由于这项研究只在低速下进行，所以在高速下弯曲手臂的好处可能更明显。

Yegian plans to do more testing to find out.

耶吉安计划做更多的测试来找出答案。

He told The Guardian, "We have a pretty good idea now that energy is why we keep our arms straight when we’re walking and there’s probably a specific reason for bending your arms during running."

他在接受《卫报》采访时表示:“我们现在有了一个很好的想法，那就是能量是我们走路时保持手臂伸直的原因，跑步时弯曲手臂可能有一个特定的原因。”