Why Do Tiny Children Look So Ridiculous When They Run?

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Photo: 145/Dana Hoff/© Corbis. All Rights Reserved.

Watching a little kid run is quite a thing to behold. Their tiny legs swing wildly as their hands flail out to their sides, their heads bobbing jerkily along as they take their frantic yet short little steps. Inspired by watching his own young children scamper about, Jim Usherwood, who studies locomotion at the University of London, decided to investigate what on Earth is up with the crazy way toddlers run. 

The short and somewhat obvious answer: Their legs are just kind of stubby compared to the proportions of an adult’s body. Usherwood’s results, published recently in the Journal of Experimental Biology and reported by Science News, suggest that it’s not that they’re still learning how to run; instead, they’re just doing the best they can with their squat little bodies. Proportion-wise, their little legs simply aren’t as long as adults’ relative to the length of their upper bodies, and so toddlers aren’t able to lift their legs off the ground long enough to create the even strides of an older runner. “Even when they think they’re running, they’re barely getting off the ground,” Usherwood told Science News.

Adults, on the other hand, what with their longer legs, “have time to summon up the muscles needed to bound up into the air,” writer Laura Sanders explains. “But children’s short legs left them with less time to bound, producing what looks like a herky-jerky toddler trot.” Scientists: Always answering questions no one really ever asked in the first place.