BICYCLE helmet standards have a design flaw that could leave cyclists vulnerable to serious head injuries, say researchers in Belgium. The current standards fail to protect one of the most vulnerable parts of the human head 鈥� the temple. Yet the researchers have shown that the temple is a common impact site.
Bart Depreitere, Carl Van Lierde and their colleagues at the biomechanics lab of the University Hospital Gasthuisberg Leuven and the Catholic University of Leuven studied head injuries in 86 cyclists who had been involved in accidents. They found that 57 per cent of them had suffered impacts to the side of the head, and a further 27 per cent had suffered impacts to the front (Accident Analysis and Prevention, in press).
Helmets do protect against some of these injuries, but most current helmet designs leave the temple unprotected, says Depreitere. 鈥淭he temple area is a critical site, because the bone is thin. There is a high incidence of brain injuries from impacts in this area.鈥�
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He says that nearly a fifth of cyclists who sustain head injuries receive a blow in the vicinity of the temple. Depreitere says that preliminary tests with crash-test dummies show that this can happen because the shoulder does not always prevent the cyclist from hitting the side of their head when they fall.
A simple tweak to helmet design would do the trick, says Depreitere. 鈥淚 think that an extra piece just in front of the ear, a couple of centimetres or so, would protect the temple.鈥�
He also criticises European and American standards for bicycle helmets, which state that the head of the wearer should be cushioned so that it never accelerates more than 300 g in a 1-metre drop. Depreitere says that while this standard will help to protect against a skull fracture, research shows that many of the more serious head injuries, such as contusions and haemorrhages, were the result of rotational acceleration in which the head twists. 鈥淚t is certainly wrong that there鈥檚 nothing in the standards about rotational acceleration,鈥� he says.
鈥淲e have been urging more complete head coverage for bicycle helmets for quite some time,鈥� says Ed Becker of the Snell Memorial Foundation in North Highlands, California, a research organisation that has taken the lead in setting helmet standards around the world. 鈥淏ut even as they are, current bicycle helmets have an excellent record for protecting wearers.鈥�