Abstract
This paper describes different helmet test methods. The aim is to get an insight into: (1) how the helmet can protect the brain from injury; (2) the mechanisms by which head impacts cause brain damage; and (3) the appropriate tolerance levels. The paper describes helmet standards for cyclists in more detail. It is concluded that standards play both an important and effective role in defining minimum protection levels in many sporting and recreational activities. However, the standards should not be used as an excuse for a manufacturer not to develop something better. The standards must not be so stringent that users will ignore them, or that government bodies fail to apply them.