Beschreibung:
<jats:title>Abstract</jats:title>
<jats:p>Bicycle helmets are intended to reduce the risk of head injury to a cyclist. The modern style of helmet contains a thick layer of polystyrene designed to compress and absorb the energy of an impact; this is usually covered by a hard exterior. Helmets have been around for some 20 years but their effectiveness remains in question and, as Adrian Cook explains, is the subject of a heated debate.</jats:p>