Cyclists who are wearing a helmet at the time of an accident significantly reduce their risk of suffering a fracture of the skull and cut their risk of concussion by 54%, a new study has found.

Swedish researchers set out to assess the impact of bicycle accidents on the brain using computer-simulated reconstructions of three actual accidents, during which the cyclists had not worn helmets and had sustained head injuries.

"We have recreated kinematics of three bike accidents where riders lost control of the situation, fell and hit their head. We captured the cyclists' movements during the accidents and then applied the kinematics in terms of speed, just before the blow to the head, on a detailed computer model," the researchers explained.

Kinematics is a branch of mechanics which looks at the movement between points.

In order to assess the impact on the brain, the researchers compared the simulations of the crashes with CT images that showed bleeding in the brains of the victims. They then conducted simulations both with and without helmets to assess what difference this could make.

The researchers were able to see how much the brain tissue was stretched during the crashes. The tissue was tretched most in those areas where the impact occurred', they noted. However, in the simulation of the three crashes, it was found that an ordinary bicycle helmet reduced the brain tissue's stretch by between 33 and 43%.

"Given the factors in our study, we have also been able to see a reduced risk of 54% for concussion when using bicycle helmets," they said.

They also found that helmets significantly lowered the risk of skull fractures.

"We saw a great reduction of stress on the bones as a result of wearing a bike helmet, from 80 megapascals down to 10 megapascals. This figure indicates how much load you put on a given surface, and translated into more understandable terms, this means a reduction from 100% risk of skull fracture down to 10% for those wearing helmets."

Details of these findings were published in the journal, Accident Analysis & Prevention.