Impeccable. Experts in self-defense and mixed martial arts say Zidane’s head butt was a flawless demonstration of the form. He positioned his feet close to his opponent and stepped into the blow, contracting his abdominal muscles to curve into the attack. He was also careful to keep his chin down as he approached, which helped him land the strike with the top of his head as opposed to his brow or face.
Zidane employed a classic “forward head butt,” favored by street fighters in Europe and the United States. Also known as the “Liverpool kiss” or the “Glasgow kiss,” the forward head butt is used most often on an adversary’s face. The head-butter tries to smash the relatively hard bone at the top of his head into the head-buttee’s softer nose, cheeks, or jaw. Aiming for the mouth can do a lot of damage, but it can result in a laceration for the attacker. Likewise, it’s very important to avoid forehead-to-forehead contact.
5 Reasons Why I Don’t Have a Large Problem With Zidane’s Headbutt