In an interview with Huffington Post (via Blabbermouth), Babymetal have revealed that they were not aware of what heavy metal was before joining the group.
The revelation came about when band members Yuimetal and Moametal were asked about how physically draining BabyMetal's live performances are.
"When I first started, my stamina could not keep up," says Yui Mizuno (a.k.a. Yuimetal). "I did not know what metal was, so I never headbanged before ... I used to have muscle pain that lasted three days ... But now I am used to it and I have more stamina now."
Moa Kikuchi (a.k.a. Moametal) added: "When [I first became part of the band], I had not danced before [to heavy metal music]. I did not know how to make the choreography look good, and like how Yuimetal was saying, I did not know metal, so the choreography was hard to understand; my neck started to really hurt, it was difficult. But now I have got used to it. I like feeling one with the audience, making the whole venue feel like one, it makes me happy."
Babymetal's debut album was released on February 26th.