THAT'S THE WHY:HAVE YOU ever watched someone highly trained in karate as they break a block of wood or even a brick with their hand?

A study at Imperial College London and University College London sought to find out why karate experts can deliver such a powerful punch.

“Karate punches are interesting because they represent a rapid, ballistic movement, where performance is not significantly determined by muscular strength,” write the study authors in the journal Cerebral Cortex.

They recruited 12 male, karate black-belt volunteers and also 12 non-karate-trained volunteers to act as controls.

And when the researchers analysed their punches in the lab, they saw some important differences between the groups.

“We found that when executing a short-range punch, karate experts co-ordinate the peak velocities of the shoulder and wrist such that the two segments move in unison with a higher degree of accuracy than non-experts,” state the authors, who argue that the ability of karate experts to co-ordinate those peak velocities allows them to “maximise the punch force and its rate of change”.

Using brain scans, the researchers also saw differences between the experts and novices in parts of the brain involved in movement – particularly in the white matter, which is involved in carrying signals from one region to another.

“The karate black belts were able to repeatedly co-ordinate their punching action with a level of co-ordination that novices can’t produce,” said researcher Dr Ed Roberts in a press release.

“We think that ability might be related to fine tuning of neural connections in the cerebellum [brain region], allowing them to synchronise their arm and trunk movements very accurately.”