We all fall down.
Many of us used to sing the famous nursery rhyme as children. But, although perhaps more likely to take a tumble while at pre-school, humans are fairly likely to hit the deck as adults, too.
It's because we're not actually all that good at walking. Or at least that's what researchers at Purdue University in Indiana, US, have found.
The scientists report that humans are 'surprisingly bad' at walking. We're prone to clumsiness, and not just as children or when into old age.
The experts at Purdue say that walking is 'inherently difficult' for people after finding that falls are the third leading cause of unintentional injuries in those aged between 18 and 35.
Students were asked to send regular updates when they'd stumbled, slipped, or had some other dodgy mishap in 24-hour time frames over a 16-week course.
According to the study, 58 per cent of injuries occurred while people were walking. The most likely cause was a slip (48 per cent), while tripping over took up 25 per cent.
The report states:
The fact that the majority of falls occurred while walking supports the prevailing argument that bipeds [animals with two feet] are mechanically unstable and also demonstrates that walking is a challenging task.
These results address an understudied yet important question, and highlight the mechanically unstable nature of bipedal locomotion.
So there we have it - we're naturally unstable. Bipedal locomotion, it seems, is a little challenging for us. Maybe we should've stuck to walking on all fours?