Researchers have revealed that juggling can significantly improve networking in the brain.
The popular trick strengthens brain's white matter through which messages pass within the nervous system.
Lead researcher Jan Scholz from the University of Oxford gave 24 young men and women training packs for juggling and had them practise for half an hour a day for six weeks.
The study showed a significant increase in the white matter in a part of the brain involved in connecting what we see to how we move, regardless of how well they performed while juggling.
This suggests that the learning process is itself important for brain development.
Although the research team found increases in grey matter, but differences in the size and timing of the grey- and white-matter changes appear independent.
"More white matter on its own might mean you can move more quickly, but you'd need the grey matter to make sure your hands were in the right place," New Scientist quoted Scholz as saying.
Further analysis of the jugglers' brains again after four weeks without juggling showed new white matter had stayed put and the amount of grey matter had even increased.
This could be why, when we learn a new skill, we retain some ability, no matter how long ago we last practised, said Scholz.
He suggests that developing juggling-based training programmes can help people with brain injuries.
The study appears in Nature Neuroscience.