Do you have calluses on your feet? Don't fear them, though. New research has revealed that foot calluses — thickened skin that forms naturally when one walks barefoot — have evolved to protect the feet and provide for comfortable walking in perhaps ways that shoes can't match.

　　你脚上有茧吗？不要怕它们。新的研究表明，脚茧作为一种赤脚行走时自然形成的厚皮，可以让我们的行走更加舒适，还能起到保护脚的作用。某种程度上来说，穿鞋子都达不到这样的效果呢。

　　Unlike shoes, foot calluses offer protection without compromising sensitivity or gait, according to a study published in June online in the journal Nature. Shoes, in contrast, reduce sensitivity in the foot and alter the way that the impact forces transfer from the foot to joints higher up the leg.

　　《自然》杂志6月在线发布的一项研究表明，与鞋子不同的是，脚茧提供的保护并不会影响脚部的敏感度和步态。相比之下，鞋子会降低脚部的敏感度，并会改变从脚部传递到腿部上方关节所受到的冲击力。

　　The researchers — from institutes in the United States, Germany and Africa — stressed that their findings don't demonstrate that walking barefoot is healthier than walking in shoes. At its core, the study is about human evolution.

　　来自美国、德国和非洲研究机构的专家强调，他们的发现并不能证明赤脚行走比穿鞋走路更健康。这项研究的核心是人类进化。

　　Yet the fact that we have evolved to walk barefoot, and that barefoot walking is mechanically different from walking in shoes, may imply that going barefoot can impart certain long-term health benefits worth investigating, the researchers said.

　　但研究人员说，人类一路进化到能够赤脚行走，并且它和穿鞋行走从物理上来说是不同的，这个事实可能意味着赤脚行走对健康有长期效益，值得人们研究。

　　"It is fun to figure out how our bodies evolved to function," said Daniel Lieberman, professor of human evolutionary biology at Harvard University, who co-led the study. "The sensory benefits of being barefoot might have health implications, but these need to be studied."

　　这项研究的带头人之一，哈佛大学人类进化生物学教授丹尼尔·利伯曼说：“研究人体功能如何进化很有趣。赤脚行走所带来的感官益处可能会促进健康，但还需要进一步研究。”

　　For most of human's 200,000-year existence, we walked barefoot. The oldest discovered footwear dates to about 8,000 years ago, although there is indirect evidence of sandals and moccasins tens of thousands of years before this, the researchers said. Cushioned shoes are even more recent — only about 300 years old.

　　在人类20万年进化史的大部分时间里，我们都赤足走路。研究人员说，最早发现的鞋可以追溯到大约8000年前，尽管在这之前的数万年里，有间接证据表明凉鞋和鹿皮鞋的存在。软底鞋是最近才出现的——只有大约300年的历史。

　　Because calluses are the evolutionary solution to protecting the foot, Lieberman's team set out to assess how these formations might differ from shoes in maintaining grounding and comfort. Their study examined the foot calluses of more than 100 adults, the majority from Kenya. About half of the subjects walked barefoot most of the time, and half mostly wore shoes.

　　因为老茧是保护脚部而进化出的功能，利伯曼的团队开始评估它在保持脚底舒适度方面与鞋子的不同之处。他们检测了100多名成年人的脚茧，其中大多数来自肯尼亚。大约一半的受试者大部分时间都是赤脚行走，一半的受试者主要穿着鞋子。

　　Among the barefoot walkers, the thickness of the calluses did not dampen tactile sensitivity, or the ability of the foot to feel the sensation of the ground while walking. Shoes, with their cushioned bottoms, clearly mute this sensation.

　　在赤脚行走的人当中，老茧的厚度并不会降低触觉的敏感性，也不会降低步行时脚部对地面的感知力，而软底鞋明显地减弱了这种感觉。

　　However, very thick calluses don't simply act like shoe cushions. The callus thickness can protect against heat or sharp objects, providing comfort and safety, like shoes can. But the sensory receptors in the foot that detect ground surface differences still transmit signals to the brain.

　　然而，厚老茧并不像鞋底一样简单地起到缓冲作用。茧的厚度可以防止高温或尖锐的物体，就像鞋子一样提供舒适和安全。但是，脚内检测地面差异的感觉受体仍然会向大脑发送信号。

　　This uninhibited signal — that sensation of feeling the earth — may help the barefoot walker keep balance, strengthen muscles and create a stronger neural connections between the feet and the brain.

　　这种不受抑制的信号，即对地面的感知力，可能有助于赤脚行走的人保持平衡，增强肌肉，并在脚和大脑之间建立更强大的神经连接。

　　"We suggest children to walk barefoot on humid grass with the purpose to stimulate the afferents (nerves traveling to the brain) for developmental reasons," said Thomas Milani, a professorship of human locomotion at the Technische Universität Chemnitz in Germany, who co-led the study.

　　这项研究的带头人之一，德国切姆尼茨理工大学的人类运动教授托马斯·米兰尼说：“我们建议儿童光脚走在潮湿的草地上，这样可以刺激大脑的传入神经（传到大脑的神经），有利于发育。”

　　The researchers also found that walking in shoes softens the initial impact of the footstep but ultimately delivers more force to the joints compared with what is seen in thick-callused individuals. This, too, may have health implications for the knees and hips, something that should be studied, the researchers said.

　　研究人员还发现，穿鞋行走可以减轻脚部受到的最初冲击，但与有厚茧的个体相比较，它最终会将更大的力传递到关节上。研究人员说，这也可能对膝盖和臀部的健康产生影响，这一点值得研究。

　　Paul Zehr, a professor of kinesiology and neuroscience at the University of Victoria, British Columbia, Canada, added that one of the study's limitations is that tactile sensitivity was assessed at rest, with a device that sent vibrations into the sole, and so these results may not necessarily hold true for walking.

　　加拿大不列颠哥伦比亚省维多利亚大学运动生理学和神经科学教授E.Paul Zehr补充说，这项研究的局限性之一是，触觉敏感度是在休息时进行评估的，用的是一种能向足底发出振动的设备，所以这些结果可能并不一定适用于走路。

　　Barefoot walking isn't the best idea for everyone, despite its evolutionary basis. People with diabetes and peripheral neuropathy can wound their feet and not realize it. Lieberman's team would like to investigate the practicality of wearing thin sandals or moccasins, which might allow for a lot of tactile stimulation compared to cushioned shoes but offer added protection from abrasions.

　　赤脚走路尽管有进化理论基础的支撑，但它也并非有利于所有人。患有糖尿病和周围神经病变的人，可能因为赤足走路伤到脚而不自知。利伯曼的研究小组希望研究穿薄凉鞋或软皮鞋的实用性，与软底鞋相比，这可能会带来很多触觉刺激，但可以提供额外的防磨损保护。