I want to preface this article by saying that almost any martial art can work if you train the right way. But the problem is that many of the martial arts on this list aren't being taught the right way, with real-life sparring and real-life applications. Once you take the self-defense application of the style out, then you are taking the martial out of the art. Then it is just art. Yes, there is always an exception to every rule, but this list is a generalization. Also, if you are a woman looking for a martial art to learn for self-defense, you do not need to look past jiu jitsu. We also have a list of other useful martial arts to learn.
Okay now that the preambles are out of the way, let's go down to our list of worst martial arts to learn if you want to be able to protect yourself. These are not ranked in order or degree of badness---they are listed randomly.
1. Tai Chi
Is Tai Chi even considered a martial art anymore? I mean don't get me wrong, there are plenty of health benefits for training tai chi, especially for seniors. But from a self-defense standpoint, I don't think it should really be considered a martial art. If you don't know, Tai Chi is a Chinese martial art that emphasizes relaxed movements and to meet your opponent's force by following through with their motion, instead of meeting their force with your force.
There are many benefits behind the teachings of Tai Chi, including proper breathing, proper movement, and meditation. So if you want to train it for its health benefits, I highly suggest it. But if you want to train in it thinking you can defend yourself with it, you would be sorely mistaken.
In China, a Tai Chi master tried to challenge an MMA fighter to a fight. It did not end well for the Tai Chi master. Take a look below:
I will grant that there are some uses to aikido, such as learning how to break fall and learning the basic biomechanics of joint locks. But in terms of real-world effectiveness, it ranks near the bottom. The slow, rhythmic, resistance-free, and choreographed practice makes it extremely impractical for self-defense. Aikido evangelists say that they do not spar with resistance in aikido because joint locks are dangerous and you can hurt someone if you spar. But that's BS because you do not have to spar with 100 percent resistance or strength. You can still spar at a moderate pace and simulate real world fighting without getting hurt. Thankfully, some aikido schools are starting to implement full contact sparring into their classes to make aikido useful as a martial art.
Capoeira is a super cool art to learn. But it is definitely not useful as a martial art. You learn some cool acrobatic kicks but you don't really learn anything else useful. Most sparring is done with rhythmic movements to music and no contact is made with your kicks. So basically, you and your opponents are trading kicks back and forth to see who has cooler-looking kicks, but can't hit each other with your kicks.
I did a bit of capoeira myself a few years back to improve my kicks and my sparring partners noticed the improvement in my leg dexterity. So if you are supplementing your capoeira with another useful martial art, capoeira can improve your fighting ability. But by itself, it is pretty much useless for fights.
4. Ba Gua Zhang
Ba Gua Zhang is another "internal" Chinese martial art developed on Wu Dang mountain. I don't see too many schools teaching this style near me but it is still a style much alive in China and other parts of Asia heavy on Taoist philosophy. The main philosophy behind this style is to use circular motion to defeat your opponent. In principle, it sounds somewhat sound---angular motion is a principle in many effective martial arts. But as you can see in the video below, what sounds good in principle doesn't always translate to effective practice.
5. Any No-Touch Martial Art
This really shouldn't even be listed right? But apparently there are still some people that think no-touch martial arts work. I see videos of this all over social media and it irates me that people are still fooled by these charlatans. If you don't know, no-touch martial arts is a martial art where they claim that your opponent can be defeated without physically striking or grappling your opponent. The claim is that you can use your inner "chi" to defeat your opponent. Here are a few examples in the video below. And then the second video shows what happens when no-touch martial arts get tested.
I know many people reading this would want me to include tae kwon do, kung fu, or karate on the list. While I admit that many tae kwon do, kung fu, or karate schools don't train their students the right way to be effective martial artists---but the fundamentals of the three are sound. After training in them for awhile, even with very little sparring, you should develop enough foot and hand dexterity and coordination to be able to fend off someone who is your size, not athletic, and do not know what they are doing. Additionally, I do feel that there are enough schools out there that do teach these styles for real world application that it would be inappropriate to lump them in with this list.