{"id":28680,"date":"2023-06-16T18:43:11","date_gmt":"2023-06-16T16:43:11","guid":{"rendered":"https:\/\/www.sciencefocus.com\/?p=145928"},"modified":"2023-06-16T19:38:26","modified_gmt":"2023-06-16T17:38:26","slug":"the-flash-heres-the-biological-limit-to-how-fast-humans-can-actually-run","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/rss_feed\/the-flash-heres-the-biological-limit-to-how-fast-humans-can-actually-run\/","title":{"rendered":"The Flash: Here\u2019s the biological limit to how fast humans can actually run"},"content":{"rendered":"

Will we all be sprinting like The Flash in future? <\/p>

By Stephen Kelly\n \t\t<\/p>

Published: Friday, 16 June 2023 at 12:00 am<\/p>

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There is no firm consensus on how fast The Flash, the DC universe\u2019s speediest superhero, can run. One story clocks him at 2,535 miles per hour (over 4,000km\/h), for instance, which is faster than most fighter jets. While in Zack Snyder\u2019s Justice League<\/em>, he runs faster than the speed of light, 186,000 miles per second \u2013 so fast, in fact, that he violates the laws of physics and turns back time.<\/p>\n

What is certain, however, is that for the likes of you and me, running at those speeds would be as unlikely as they would be perilous. Our faces would melt, our legs would break apart\u2026 I can barely do the \u2018Couch to 5K\u2019 plan as it is.<\/p>\n

So how fast can human beings run? For that, we would need to look at the closest thing humanity has to The Flash: retired sprinter Usain Bolt.<\/p>\n

In 2009, Bolt set a new world record by running the 100m sprint in 9.58 seconds \u2013 achieving a top speed of 27mph (43km\/h) \u2013 at the World Athletics Championships in Berlin. It\u2019s a record that is yet to be broken and, according to Mark Denny, a biology professor at Stanford University, perhaps never will be.<\/p>\n

In 2008, a year before Bolt broke the world record, Denny published a paper analysing the top speeds of various athletics competitions<\/a> \u2013 as well as those of greyhound and horse races \u2013 since the 1920s. And in many cases, he found the same pattern.<\/p>\n

\u201cPerformances were clearly plateauing in all races,\u201d he says, \u201cand has plateaued in some of them.\u201d<\/p>\n

He found that horses, for example, reached their limit with Secretariat in 1973. \u201cNo horse has come close to the records he set,\u201d says Denny. \u201cThey keep breeding horses to go faster and they just keep breaking down. The limits are real.\u201d<\/p>\n

Is there a limit to how fast humans can run?<\/strong><\/h2>\n

As for humans, Denny has used his data to make a bold prediction: no human being will ever run the 100m sprint faster than 9.48 seconds, just 0.1 seconds under Bolt\u2019s current record.<\/p>\n

\u201cThere was a real sense of disappointment in response to the paper [with the prediction],\u201d he says. \u201cPeople didn\u2019t like the idea of an Olympics where world records wouldn\u2019t be broken. There was a chance that Bolt could have done it in 9.48 but then he aged out on that. I was rooting for him to break it.\u201d<\/p>\n

According to Denny, the reason for this proposed plateau is due to the basic biological limits of the human body. Four-legged animals like cheetahs \u2013 with their long legs, light body weight and flexible spine \u2013 are designed for short-term speed. Bipedal runners, meanwhile, are built for endurance.<\/p>\n

\u201cMuscles can only contract as fast as the actin and myosin [two key components of muscle fibre] can turn over,\u201d he says. \u201cYou can get some advantage by making longer filaments in the muscle but then you can only make them so long.<\/p>\n

\u201cUsain Bolt is 196cm tall. You might get somebody who is 218cm and really well-proportioned. Yet even then, tendons and bones can only put up with so much. Even if you made the bones more robust, they would then be heavier, negating what you\u2019re trying to do.\u201d<\/p>\n

The only way you could go beyond these biological limits, says Denny, is with genetic engineering<\/a>. Although don\u2019t go expecting us to be trotting around like centaurs any time soon. \u201cIt\u2019s more likely to be used to gain more powerful muscles and longer legs,\u201d says Denny.<\/p>\n

\u201cOr to tweak the design here and there: \u2018let\u2019s move this particular muscle to a different place\u2019 and so on. That\u2019s going to be really strange. Performance-enhancing drugs are scary enough but I hope I\u2019m not around to see that.\u201d<\/p>\n

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About our expert<\/strong><\/h4>\n

Mark Denny is a biology professor at Stanford University who specialises in biomechanics, which uses the principles of engineering and physics to understand how animals function. His research has been published in academic journals including Ecology And Evolution, <\/i>and The Journal Of Experimental Biology.<\/i><\/p>\n

Read more:<\/strong><\/p>\n