George Dillman may be the most famous among a handful of martial artists that travel around the globe to teach people the art of pressure point fighting for a hefty fee. In this video, which appeared on National Geographic, he demonstrates his ability to focus Chi, a sort of mystical energy, to knock people over without even touching them.

I don't dispute that martial artists can render a volunteer unconscious with a relatively gentle touch during a carefully-controlled demonstration. But I wonder how compliant the assistant must be.

Perhaps the underlying principle at work here is the power of suggestion rather than causing an overload to the nervous system or using a jedi mind trick.

If this method of fighting is so effective, why isn't it used in mixed martial arts competitions? Perhaps because it takes years to master, is too dangerous to use on a delicate cage fighter, or can be countered by an unintentional wiggle of the tongue or toe.

The explanations for pressure points and acupuncture have a lot in common. In fact, the spots on the body where martial artists are trained to strike lie along the so-called meridians of the prickly therapy. A recent study of acupuncture showed that it does not matter where the needles get stuck.

Faith healers can knock people out too, but their explanation is a bit different.