What Runners Can Learn From Cheetahs
跟猎豹学跑步

Back in the 1960s, researchers in Africa clocked the wild cheetah as it ran and determined that at full gallop, a cheetah reached a top speed of about 65 miles per hour, making it easily the world's fastest land mammal. No other quadruped or biped comes close. Galloping quarter horses top out around 47 miles per hour, while sluggish humans, in the person of the world record 100-meter sprinter Usain Bolt, have attained a top speed of less than 28 miles per hour. Even the bullet-trainlike greyhound, similar in build and running style to the cheetah, doesn't surpass 40 miles per hour.

20世纪60年代，非洲的研究人员测量了野生猎豹的奔跑速度，发现猎豹在全速奔跑的时候，速度可以达到每小时65英里左右，轻松夺取陆生哺乳动物的速度桂冠。没有任何其他四足动物或两足动物能够望其项背。疾速奔跑的夸特马速度可以达到每小时47英里左右，而行动迟缓的人类，即便是创造了世界100米纪录的短跑运动员尤塞恩·博尔特(Usain Bolt)，最快的速度也还不到每小时28英里。灰狗拥有子弹列车一般的体型，生理构造和奔跑方式都和猎豹相似，就连它的速度也未能超过每小时40英里。

So what is it about the cheetah and its particular physiology or running form that allows it to set such a blazing pace? And can a better understanding of cheetah biomechanics help humans to move faster?

到底是什么，是猎豹特殊的生理机能还是奔跑方式让它拥有了如此惊人的速度？进一步认识猎豹的生物力学能让人类的速度更快吗？
 

Those were the questions that motivated a group of scientists at the Structure and Motion Laboratory at the University of London, who decided to compare the cheetah with one of its near rivals in speed, the greyhound.

为了回答这些问题，一组来自伦敦大学结构与运动实验室的(Structure and MotionLaboratory at the University of London)科学家们决定，要对猎豹和与它速度近似的灰狗进行对比实验。

"The two animals are quite alike in terms of body mass and running form," says Alan H. Wilson, a professor at the Royal Veterinary College at the University of London, who led the study, which was published in The Journal of Experimental Biology.

“这两种动物在体重和奔跑方式上十分相似，”伦敦大学皇家兽医学院(Royal Veterinary College at the University of London)的教授艾伦·威尔逊(Alan H. Wilson)说。这个课题由他负责，研究结果发表在《实验生物学期刊》 (The Journal of Experimental Biology)上。

Both animals employ a running form known as the rotary gallop. Their legs churn in a circular motion, the animal's back bowing and its hind legs reaching almost past its ears at full stride. (Tongues tend to loll, too, but there's no indication that this attribute affects speed.)

猎豹和灰狗都采用了一种被称作“旋转式疾驰”的奔跑方式。它们的四条腿都在做剧烈的圆周运动，背部弓起，在全速奔跑时，后腿几乎超过了耳朵。(它们通常会把舌头伸在外面，但是并无迹象表明，这个特征对速度有影响。)

"Up to a speed of about 40 miles per hour, there's very little difference," Dr. Wilson says. "But what happens after that," when the cheetah finds another gear and accelerates to 65 miles per hour, "is something we'd like to understand. We believe it can help us to better understand the determinants and limits of speed itself."

“时速在大约40英里以下时，差别并不明显，”威尔逊表示。“不过，时速超过40英里之后的情况”——猎豹启用了别的什么“传动装置”，加速到每小时65英里——“才是我们想弄清楚的。我们相信，这能帮助我们更好地理解速度的决定性因素和限制性因素。”

But closely studying cheetahs in the wild is logistically challenging, especially if you want exact measurements of running force and stride. So the researchers turned to captive cheetah populations at a zoo in Dunstable, England, and a sanctuary in Pretoria, South Africa. The animals were extensively measured and filmed.

然而，在野外近距离地研究猎豹是一件逻辑上说不通的事情，如果你想精确测量它们奔跑的力度和步幅，情况就更是如此。所以，研究人员将目光转向了人工看管之下的猎豹群，它们的家园是英国邓斯特布尔的一个动物园和南非比勒陀利亚的一家动物保护所。研究人员对它们进行了大量的测量和拍摄。

Then some of the English cheetahs were taken to the performance lab and encouraged to chase a chicken-meat lure along a 90-meter track dotted with force plates to chart their strides. Meanwhile, high-speed cameras recorded their every movement from multiple angles.

之后，研究人员把英国动物园的一些猎豹带进了行为实验室，他们用鸡肉充当诱饵，引诱它们沿着一个布满测力板的90米跑道奔跑，以便精确测度它们的步伐。同时，高速摄影机从多个角度将它们的一举一动记录下来。

The researchers repeated the experiment with trained racing greyhounds, then compared the two animals' pace and form.

研究人员在竞赛灰狗身上做了同样的实验，之后将这两种动物步法和形态进行了对比。

The first thing they noted was that captive cheetahs are relatively slow, compared with their wild brethren. The galloping zoo-bred cheetahs topped out at a little less than 40 miles per hour, slightly lower than the top speed for the greyhounds.

他们的第一个发现是，与野生猎豹相比，人工看管之下的猎豹速度相对较慢。动物园繁育的猎豹在急速奔跑时的最快速度还不到40英里每小时，比灰狗的最快速度稍慢。

"That finding was not really unexpected," Dr. Wilson says. Cheetahs that live in zoos do not have to feed themselves. They have less motivation to run hard, even when a chicken lure is waggled enticingly in front of them.

威尔逊说：“这个结果并不在意料之外。”动物园里的猎豹不需要自己猎食。甚至当美味的鸡肉在它们眼前晃荡时，它们仍缺乏奋力奔跑的动力。

"They also don't necessarily learn to gallop as fast," Dr. Wilson says. "There is almost certainly some amount of speed that depends on learning" to be swift enough to bring down prey.

“它们也不需要学习快速奔跑，” 威尔逊说。“几乎可以肯定，一部分的速度依赖于学习”，学习的目的则是快到足够捕杀猎物的程度。

Dr. Wilson is now collecting data on wild cheetahs, but even in the zoo-bred animals, there were hints of their capabilities. When the cheetahs "felt like it," Dr. Wilson says, their leg turnover rate spurted and their pace dramatically increased. They began bringing their legs around faster and faster, their strides lengthening, even as the frequency of their strides increased.

威尔逊目前正在搜集野生猎豹的相关数据，但是，即使是动物园繁育的猎豹也体现了它们的潜力。威尔逊说，当猎豹“有心情”的时候，它们翻腿的频率和步幅就会快速增加。它们的腿动得越来越快，迈步频率提高的同时，步幅也在加大。

The greyhounds, on the other hand, maintained a fairly even stride frequency throughout their entire run.

然而，灰狗在整个奔跑过程中都保持着相当稳定的迈步频率。

The cheetahs also hit the force plates differently from the greyhounds, their paws remaining on the ground slightly longer -- an action that presumably allows the legs to absorb more of the forces generated by the pounding stride.

猎豹碰触测力板的方式也和灰狗不同，它们的脚掌在地面停留的时间稍长。据推测，这样的举动可以使腿部吸收更多脚掌撞击地面时产生的反作用力。

"One of the limits to speed is that, at some point, you can generate more force than the muscles can withstand," Dr. Wilson says. Striking the ground with such shattering oomph can cause muscles to shred. The cheetahs reduced this risk by letting their paws linger a fraction of a second longer on the ground than the greyhounds did.

威尔逊说：“速度的限制因素之一是，到了某个临界点，运动过程产生的力量会让肌肉无法承受。”以如此震撼的巨大力量击打地面会引起肌肉撕裂。猎豹降低了这种危险，方法就是延长脚掌在地面停留的时间，比灰狗多停留几分之一秒。

The lessons for human runners are somewhat abstract, since we have only two legs and, with rare exceptions, cannot curl them up past our ears, as cheetahs and greyhounds do. "The cheetah's back functions as an extension of its hind legs," Dr. Wilson points out, its spine coiling and extending with each stride, as ours cannot.

这个经验对于人类跑步者来说有些抽象，因为我们只有两条腿，而且大多数情况下，我们也不能像猎豹和灰狗那样，将腿伸展到可以超过耳朵的程度。“猎豹的背部延伸了其后腿的功能。” 威尔逊指出，猎豹的脊柱会随着每次迈步而一蜷一伸，我们却不能这样。

But there are tips we can glean from the cheetah. The speed with which a creature brings its leg back around into position appears to be one of the main determinants of speed, Dr. Wilson says. The faster you reposition the leg, the faster you'll move.

不过，我们也能从猎豹身上获得一些启示。威尔逊说，生物将腿收回原位的快慢似乎是奔跑速度的主要决定因素之一。收腿的速度越快，你就跑得越快。

But swift leg turnover requires power. "Compared to the greyhound, the cheetah has bulky upper legs," Dr. Wilson says. Its powerful thigh muscles allow its legs to pump more rapidly than the spindly greyhound's can.

但是快速移动四肢需要力量支撑。“与灰狗相比，猎豹的大腿更加强壮，”威尔逊说。有了强健的大腿肌肉，猎豹的腿就比灰狗纤长的腿移动得更快。

So strengthen your thighs.

所以，把你的大腿练壮实些吧。

And perhaps invest in lightweight racing shoes. "Having less weight in the lower portion of the leg aids in swift repositioning" of the limb, Dr. Wilson says.

也许，你还应该买一双轻便的竞赛跑鞋。威尔逊表示：“减轻腿部末端的重量能加快收腿的速度。”

Finally, while a dangling lure is optional, being hungry, Dr. Wilson says, at least metaphorically, "probably helps quite a bit."

最后，虽然悬挂的诱饵可有可无，威尔逊说，但至少是从喻义上来说，饥饿状态“可能会很有帮助。”

Gretchen Reynolds is the author of "The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smarter, Live Longer" (Hudson Street Press, 2012).

格雷琴·雷诺兹(GretchenReynolds)是《前20分钟：神奇科学告诉你如何更好地运动、锻炼和生活》(The First 20 Minutes:Surprising Science Reveals How We Can Exercise Better, Train Smarter, LiveLonger)的作者。(哈德森街出版社，2012年)

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