Just like most areas of human endeavor, martial arts is full of pseudoscientific bullshit, commonly known by the collective title of Bullshido. Although some fighting techniques are bonafide sports - such as karate, judo, Taekwondo etc - and are recognised by the Olympic committee for example, many flirt with or even outright embrace pseudoscience and various forms of woo. To be honest, this is not a subject many of us in Edinburgh Skeptics are familiar with so we'll comment only on the obvious bullshido.
One of the most heavily criticised techniques is the modern martial art of Aikido. Without going into too much detail, it is a mix of judo-like fighting synthesised with philosophy and religious beliefs. There are numerous videos online showing masters being attacked by students and one after the other, he is able to roll them away. It has been criticised by many people as more dancing than fighting, so as a keep fit technique may be very helpful but as a self-defence style, maybe not.
Some Martial Arts Masters claim they can down someone just with a finger-touch on a pressure point, or even without even touching them! Several skeptics have offered to be the recipient of this touchless technique but excuses are often given, such as not wishing to kill the skeptic. One great video shows a Kiai master who offered $5000 that he could beat any MMA (mixed Martial Arts) proponent. Unfortunately for him it didn't go well (www.youtube.com/watch?v=gEDaCIDvj6I). One of the biggest bullshido-ists is George Dillman, who in 2005 was the subject of a Nat Geographic doc putting his "no-touch knockout" to the test. As expected, it failed. There is a lot of bullshit in martial arts. We are not denigrating the physical skills and hard work practitioners put in but as a realistic self-defense technique they are not as good as many think they are.