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Scientists have come up with an explanation for why some teenage boys go through a clumsy phase.

Research suggests the brain struggles to cope with the body's change in height during a sudden growth spurt.

The boys walk clumsily for a while as their brain adjusts, say Italian scientists.

Adolescents who grow slowly and steadily remain more coordinated, a team at the University of Bologna found in a study.

Lead researcher Dr Maria Cristina Bisi said a sudden increase in height affects the body's ability to control established motor skills, such as walking.

"Adolescents tend to show previous control of the body when growing up, but the motor control behaviour is organised on the body's dimensions," she said.

"Following a growth spurt, the body needs time to adjust to changes to the periphery, during which time a teenager may walk awkwardly, while teenagers who grow steadily are able to handle growth modifications better and so maintain smoothness and regularity when walking."

The researchers studied 88 teenage boys aged 15.

They divided them into two groups - boys who grew more than 3cm over the three-month study period and those who grew only 1cm or less.

They then analysed aspects of gait, including balance, the ability to walk smoothly and regularity of stride.

The boys walked back and forth along a corridor with wireless sensors strapped to their backs and legs, and were asked to perform a mental arithmetic task while walking.

Boys who had not had a growth spurt walked more smoothly and their stride was more regular compared with the other group, the scientists found.

The research is published in the open access journal .