I Dont know why kids think this is cool. Most talented metal bands will tell the hardcore kids that no dancing is allowed. Most hardcore kids are OBSESSED with their self-image(they say it's for getting girls) and the whole hardcore scene is the same way, my few hardcore friends are so "metro" I can't help but laugh to myself every time I see them. If hardcore dancing is skillfull then so is having an epileptic siezure.
There is no set guidline to hardcore dancing, you just wait for breakdowns in songs, and make sure you look like a total lunatic while trying to find your "own style" in your flailing.
That music club has hardcore dancing competitions.
Hardcore dancing is the worst thing to ever happen to music since disco dancing.