發表在《自然》上的一篇文章指出，一項新的研究表明，穿著跑鞋跑步其實對身體并不好，赤腳跑步反而可以避免奔跑帶來的損傷。

    This is the VOA Special English Health Report.

    Two new studies suggest that modern running shoes could increase the risk of injuries to runners.

    One study involved sixty-eight healthy young women and men who ran at least twenty-four kilometers a week. The runners were observed on a treadmill machine. Sometimes they wore running shoes. Other times they ran barefoot.

    Researchers from the JKM Technologies company in Virginia, the University of Virginia and the University of Colorado did the study.

    They found that running shoes create more stress that could damage knees, hips and ankle joints than running barefoot. They observed that the effect was even greater than the effect reported earlier for walking in high heels.

    The study appeared in the official scientific journal of the American Academy of Physical Medicine.

    The other study appeared in the journal Nature. It compared runners in the United States and Kenya. The researchers were from Harvard University in Massachusetts, Moi University in Kenya and the University of Glasgow in Scotland.

    They divided the runners into three groups. One group had always run shoeless. Another group had always run with shoes. And the third group had changed to shoeless running.

    Runners who wear shoes usually come down heel first. That puts great force on the back of the foot. But the study found that barefoot runners generally land on the front or middle of their foot. That way they ease into their landing and avoid striking their heel.

    Harvard's Daniel Lieberman led the study. He says the way most running shoes are designed may explain why those who wear them land on their heels. The heel of the shoe is bigger and heavier than other parts of the shoe, so it would seem more likely to come down first. Also, the heel generally has thick material under it to soften landings.

    But the researchers do not suggest that runners immediately start running barefoot. They say it takes some training. And there can be risks, like running when your feet are too cold to feel if you get injured.

    The study was partly supported by Vibram, which makes a kind of footwear that it says is like running barefoot. The findings have gotten a lot of attention. But the researchers say there are many problems in the way the press has reported on their paper. So they have tried to explain their findings on a Harvard Web site. For a link, go to en8848.com.

    And that's the VOA Special English Health Report, written by Caty Weaver. I'm Steve Ember.

    一位長跑發燒友，哈佛大學的人類進化生物學家丹尼爾·雷柏爾曼決定尋找這個問題的答案。他和同事們調查了200位穿鞋和光腳的長跑者，這些長跑者來自美國和以非凡毅力著稱的肯尼亞裂谷省。這些調查對象為他們提供了一系列與鞋有關親身經歷，類型包括從小就穿鞋跑步的成年人，從小光腳跑長大才穿鞋的人，以及到現在都光腳跑的人。雷柏爾曼的團隊對這些人做了一個實驗，每一類型都分為兩組--穿鞋者和光腳者。穿鞋的長跑者使用自己的跑鞋或者是愛世克斯防震系列型號為GEL-Cumulus 10s的跑鞋。在這個實驗里，他們測量長跑者的步法以及對身體的影響。

    很快，研究者發現了不同。穿鞋的用腳后跟落地，而光腳的用大腳趾或者扁平足著地。赤腳者的跑步方式使彎曲的足弓、踝關節和膝蓋上生出更多的紋路，同時需要更多步伐和小腿肚肌肉，減弱了對身體的沖擊，長跑之旅變得更加自在。在足部與地面沖撞的一瞬間，光腳者感受到其自身體重0.5到0.7倍的沖擊力，而穿鞋者的腳后跟感受到其體重的1.5到兩倍，是光腳者的三到四倍。

    雷柏爾曼非常驚訝，"過去我常常認為赤腳跑很瘋狂而且很疼。"然而，即將發布在《自然》的這項成果顯示，光腳跑可以降低疼痛和關節磨損發生的可能性。許多長跑引起的傷害，諸如外脛夾和足底筋膜炎都是壓力和沖擊造成的。