Head and neck injury risks in heavy metal: head bangers stuck between rock and a hard bass
-- Declan Patton, Andrew McIntosh, BMJ 2008;337:a2825
http://www.bmj.com/cgi/section_pdf/337/dec17_2/a2825.pdf

Young people at heavy metal concerts often report being dazed and confused, possible symptoms of mild traumatic brain injury....
Possible interventions to reduce the risk of injury caused by head banging include limiting the range of neck motion through a formal training programme delivered before a concert; substitution of adult oriented rock and easy listening music such as the controls, or others including Michael Bolton, Celine Dion, Enya, and Richard Clayderman, for heavy metal; and personal protective equipment such as neck braces to limit range of motion.