WARNING: Headbanging to Metallica, Motorhead or Megadeth could be hazardous to your health.
So concludes the first-ever study of the fin-de-siecle dance style in which aficionados of heavy metal jerk their heads up and down to a fast and furious beat.
Declan Patton and Andrew McIntosh at the School for Risk and Safety Sciences at the University of New South Wales in Australia, attended hard rock and heavy metal concerts to observe headbanging techniques.
They then worked up a biomechanical analysis, culminating in a "theoretical headbanging model."
Same effect as whiplash
In their offbeat study, published by the British Medical Journal (BMJ), the pair say that thrashing about like an electro-shocked rabbit may cause similar effects to whiplash.
A typical death-metal rhythm of 146 beats-per-minute or faster, combined with head-banging arcs of at least 45 degrees, is "predicted to cause mild head and neck injury," they say.
With faster tempos and a wider arcs, "there are definite risks of mild traumatic brain injury."
Stroke from headbanging?
Anecdotal evidence also points to the potential health hazards of thrash rock, the paper says.
"In 2005, doctors believed that Terry Balsamo, the guitarist from the band Evanescence, experienced a stroke from head banging," it notes.
So what can be done?
Metal fans could wear a neck brace while headbanging - or stick to listening to Michael Bolton, Celine Dion, Enya and Richard Clayderman, joke Patton and McIntosh.
To teens who still prefer Ultra Vomit to easy listening, the paper offers a practical example of what to avoid. It applies the "theoretical headbanging model" to cartoon wunderkinder Beavis and Butt-head, dancing to The Ramones' "I Wanna Be Sedated" at 164 beats per minute.
The range of motion of Beavis' head is about 45 degrees, which is below the injury threshold.
For Butt-head, though, the prospects are not so great. He headbangs with a range of motion of about 75 degrees, with the risk of "level one" head injuries - headaches and dizziness. - (Sapa-AFP)
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