Cracking walnuts with your head?

In the category of how do you even come up with this: check out this video of the man who won the world record for cracking walnuts with his head. He cracked no fewer than 217 in one minute.

The biggest pizza, the longest noodle, the biggest chewing-gum bubble ever blown—it’s all in the Guinness Book of Records. Whatever you think of it, people make it their ultimate life goal to break the latest world record. Still, I think cracking walnuts with your head is a particularly unusual one.

India’s S. Navin Kumar broke the previous record of 36 walnuts per minute. What I wonder is: does he have an extra-hard head, or has he simply invented the very best technique? Either way, I already get a headache just watching the video.