What are some guidelines for headbanging safely?

My kid loves heavy metal music, which means he's into headbanging. That's fine with me, I encourage his enthusiasm, but I'm concerned that he could injure himself when he really throws himself into the music. Are there particular moves that are considered safer than others? Speeds or angles that sho...

What’s the fastest way to get enough flexibility to do a split?

Starting from very inflexible, especially in the hamstrings, what’s the fastest way to get your splits down?...