Apparently wildly swinging your head to a fast beat can cause injury. Who knew? (You know, other than all the head bangers in the world who wake up with a sore neck the next day. Other than them). Apparently scientists felt the need to take some money and study this:
The researchers attended hard rock and heavy metal concerts including Motörhead, Ozzy Osbourne and Skid Row, and identified that the up-down style was the most common head banging technique. They constructed a theoretical head banging model of this popular style to examine the effect the range of head and neck motion has on injury severity. A focus group of ten musicians was used to calculate the average tempo of their favourite head banging songs.
The authors found that there is an increasing risk of neck injury beginning at tempos of 130 beats per minute related to the range of motion in the head banging style.
Oh, the humanity.