地球人到底能跑多快？

MORE THAN 130 years ago, at the first Olympic Games in Athens, Boston University law student Thomas Burke took his mark at the 100-meter dash not in a standing position, but a crouch—what was then considered an unusual starting stance.

130多年前在雅典舉行的第一屆奧運(yùn)會上，波士頓大學(xué)法律系的學(xué)生Thomas Burke在100米短跑的比賽中，沒有采用站立的起跑姿勢，而是蹲下了身子——在那時候，這可是個非常不尋常的事兒。

But far more unusual, by today's standards, was his gold-medal winning time of 12 seconds flat.

但以今天的眼光來看，更加不尋常的是，他以12秒整的成績拿到了那屆奧運(yùn)會的百米金牌。

These days, talented middle schoolers post 100-meter times better than Burke's. In March 2018, 15-year-old Briana Williams, a high school sophomore, set a world age-group record in the event with a time of 11.13 seconds. The record for boys 18-and-under is nearly a second faster still: Set in 2017 by Anthony Schwartz, the 10.15-second time would have won gold at 1980's Summer Games.

現(xiàn)在，稍有點(diǎn)天賦的中學(xué)生都能跑得比這個成績好。2018年3月，15歲的高中二年級學(xué)生Briana Williams以11秒13的成績創(chuàng)造了他這個年齡組的世界紀(jì)錄。而對于18歲以下年齡組的男選手，成績還要再快將近1秒：Anthony Schwartz在2017年創(chuàng)造了10秒15的紀(jì)錄，這個成績能拿到1980年奧運(yùn)會的百米金牌。

Today, though, on the world stage, Schwartz wouldn't even podium: In the past 30 years, only three sprinters have medaled at the Olympics with a time slower than 10 seconds. Propelled by more effective training, grippier track surfaces, faster footwear, and, yes, pharmaceuticals, competitors at every level of track and field's premier event have steadily chipped away at the world's best 100-meter times. Jamaican sprinter Usain Bolt holds the current world record: a sprightly 9.58 seconds.

而在今天，Schwartz的成績甚至不夠站上領(lǐng)獎臺：在過去30年間，只有3位短跑選手曾經(jīng)以慢于10秒的成績獲得奧運(yùn)會的獎牌。在更有效的訓(xùn)練、抓地力更好的跑道、更快的跑鞋，以及……嗯，藥物的推動下，每個級別的主要田徑賽事中，選手們跑完100米的時間都變得越來越短了。牙買加人博爾特(Usain Bolt)保持著現(xiàn)在的世界紀(jì)錄：9秒58。

The surprisingly persistent record progression is enough to make anyone ask: When will the fastest people on Earth cease to become any faster? And when they do, what will the fastest time ultimately be?

百米紀(jì)錄驚人的刷新速度足以讓人們開始好奇：什么時候會有人再度打破這個紀(jì)錄?以及……地球人到底能跑多快?

Depending on how you look at it, the answer to the first question could be "very soon," or "not soon at all." As recently as 2008, the popular perception among people who think about such things was that elite 100-meter runners were approaching the limits of possibility. Then came Bolt, who burst onto the scene at the Beijing Olympics with a record-wrecking time of 9.69 seconds—an anomalous performance, mathematicians thought, that statistical models placed two decades ahead of its time. But the following year, when Bolt broke his record by nine-hundredths of a second, he also broke, categorically, those old models. Today, revised probabilistic estimates project that his record could stand for upwards of two centuries. But who knows how that projection will measure up against reality. As applied mathematician David Sumpter has observed, Bolt singlehandedly demolished our ability to make reliable predictions about the 100-meter dash.

第一個問題的答案取決于看問題的角度，可能是“非?？?rdquo;，也可能是“早著呢”。就在不久前的2008年，人們還普遍認(rèn)為當(dāng)時的頂尖運(yùn)動員已經(jīng)接近了人類100米速度的極限。隨后博爾特就橫空出世了，他在北京奧運(yùn)會上以9秒69的成績打破當(dāng)時的世界紀(jì)錄——這個成績讓人驚掉了下巴，數(shù)學(xué)家們甚至認(rèn)為，他的成績比統(tǒng)計模型的預(yù)計早了整整20年。而在2009年，博爾特又把自己保持的紀(jì)錄提高了百分之九秒。與紀(jì)錄一同被打破的還有傳統(tǒng)的統(tǒng)計模型。如今，一項(xiàng)修正過的概率推算預(yù)測，他的紀(jì)錄甚至有可能保持兩個世紀(jì)以上。但鬼才知道這種預(yù)測到底在現(xiàn)實(shí)面前能有多靠譜。正如應(yīng)用數(shù)學(xué)家David Sumpter所言，博爾特單槍匹馬就摧毀了我們預(yù)測百米短跑紀(jì)錄的能力。

Which is one reason biomechanists approach the matter somewhat differently than mathematicians. They address the second question by investigating not when Bolt's record might fall, but by how much, based on the bodies of today's fastest sprinters.

這也是生物力學(xué)家們和數(shù)學(xué)家們在處理這個問題時采取不同看法的原因。對于第二個問題，他們考慮的不是什么時候博爾特的紀(jì)錄會被打破，而是他的紀(jì)錄會被超過多少?？紤]問題的基準(zhǔn)則是如今頂尖短跑運(yùn)動員的身體。

"Once they get rolling, the force they apply becomes a motion-based mechanism, where they use their limbs to throw a punch at the ground," says biomechanist Peter Weyand. As director of the Locomotor Performance Laboratory at Southern Methodist University in Dallas, Weyand invites many of the fastest sprinters on Earth to run in short bursts in front of high-speed, motion-tracking cameras on a bespoke, force-sensing treadmill that makes the thing you trot on at your gym look like a glorified hamster wheel.

“一旦起跑，運(yùn)動員們就成了一架精密運(yùn)行的力學(xué)機(jī)器，用他們的肢體不斷地向地面施加動力。”生物理學(xué)家Peter Weyand說道。作為南方衛(wèi)理公會大學(xué)(Southern Methodist University)運(yùn)動性能實(shí)驗(yàn)室的主任，Weyand邀請了地球上許多最快的短跑選手，來在定制的力學(xué)感應(yīng)跑步機(jī)上短途沖刺。在高速運(yùn)動追蹤攝影機(jī)前的，這些運(yùn)動員就像是輪子中的小倉鼠一樣。

Based on his observations, Weyand says the two biggest factors limiting the performance of elite sprinters are how much force they can apply to the ground, and how fast. At current top speeds of around 27 miles per hour, he says elite male sprinters like Usain Bolt put down roughly five times their body weight, in between .085 and 0.09 seconds.

根據(jù)他的觀測，Weyand說，限制短跑選手們成績的兩個最大因素是他們能給地面施加多大的力量，以及施力速度多快。在如今短跑運(yùn)動員大約43公里(27英里)的時速下，像博爾特這種頂尖男選手大約會在0.085到0.09秒的時間內(nèi)，向地面施加約等于5倍體重的力量。

Just for fun, I ask Weyand what kind of numbers a sprinter would need to complete the 100 meter dash in 9 seconds, on the nose. "To get to what would be required for nine flat, they would have to approach forces roughly six times their body weight, and a ground contact time of just over seven hundredths of a second," he says. At those figures, a sprinter could, in theory, reach a maximum speed of 13.5 meters per second—a hair over 30 miles per hour. But according to Weyand, no sprinter on Earth comes anywhere close to those numbers.

出于好奇，我問Weyand，如果想要在9秒內(nèi)跑完100米，這些數(shù)字大約需要變成什么樣。“如果想要在9秒內(nèi)跑完百米，他們他大概需要在0.07秒左右的時間里向地面施加約6倍體重的力量。”他說。理論上，如果短跑選手能夠跑出這個數(shù)據(jù)，最高時速會達(dá)到13米/秒——時速剛剛超過48.2公里(30英里)。但Weyand還說，地球上目前還沒有能接近這個數(shù)字的人類。

That probably puts the theoretical limit for the 100 meter dash closer to 9.58 than 9.00. But Weyand, for his part, thinks athletes have plenty of room to improve. "If you put together a perfect human being, and the perfect race, I could certainly see something in the low 9.40-second range, maybe a little bit faster than that, under currently legal conditions," he says.

這意味著，相比9秒，百米紀(jì)錄的極限可能還是更接近現(xiàn)在的紀(jì)錄——9秒58。但Weyand也說，運(yùn)動員們改進(jìn)的空間還很大。“如果有一個完美的人類，跑了一場完美的比賽，在當(dāng)前合理的狀況下，我覺得能看到低于9秒40的成績。”

Then again, who knows how those conditions could change. When Thomas Burke coiled into a crouch at the starting line for the first Olympic 100 meter dash, he did so without the speed-boosting benefits of modern nutrition, apparel, or training. He didn't even have starting blocks. Athletes at the Olympic Games in 2120 may well scoff at the rudimentary preparations of today’s sprinters too.

但話又說回來了，鬼才知道這個“合理的狀況”最后會變成什么樣。當(dāng)Thomas Burke在首屆奧運(yùn)會的百米起跑線上蹲下的時候，他可是完全沒有現(xiàn)代的營養(yǎng)條件、科技服裝和合理訓(xùn)練的。他甚至連個起跑器都沒有。等到2120年奧運(yùn)會時，參賽的運(yùn)動員們回頭看今天的同行，可能也是一樣的感覺。