I am not flexible, never have been, and most likely won’t be. I have attempted to do it before it ultimately ended in failure. I have searched this up and there are mixed answers. I'd like to try some more sources, so are the splits necessary or should I try to become more flexible?
I agree with Macaco Branco's answer. Just wanted to add to it.
No, splits are not required in order to do Taekwondo, even as a high ranking black belt.
Flexibility is something Taekwondo schools work on quite a lot. A good 1/4 to 1/3 of all class time is spent doing something that directly affects flexibility. And most of the rest of the class will often indirectly work on flexibility in some way.
Outside of class, students are expected to stretch everyday at least twice a day, if not more. For a lot of students, it becomes kind of an obsession.
When I was very active in Taekwondo, I would get up in the morning and stretch. Then I would eat breakfast. After breakfast, I would stretch. I'd stretch before TKD class, during TKD class, and then after TKD class. Before bed, I'd stretch. And all throughout the day, I would take any opportunity I could to stretch. Even if I was sitting down at a desk, I might grab my hands and stretch my wrists. I'd rotate my neck. I'd get up every now and then and rotate my spine. At home, I'd get up and do high kicks when walking from room to room. Etc.
So stretching is a big part of Taekwondo training. For many, it's something that becomes a way of life. And the more you stretch, the more flexible you'll become over time. Many, but not all, will reach the point where they can get a full split (side split and front split). It's not required, but it's something that Taekwondo people are often able to do with lots of effort over time. It just comes with the practice. It's not something you need to set as a goal, although many do have it as their own personal goal.
There are two major pain points for leg flexibility. The first is hip/groin flexibility. Without that, you're going to feel unable to get into a low horse stance, or any low stance, that's correct to form. And kicks will be limited to waist level only, without bending your base leg (cheating). So that is the first place to work on if that describes you. And hip and groin flexibility are topics you can search on YouTube for advice on how to become more flexible there.
The second pain point for leg flexibility is the hamstrings and glutes. When these are too tight, it will restrict raising your leg up without bending your base leg. This is often due to strength training without doing enough stretch work after lifting weights. Again, there are many videos showing exercises that work on increasing flexibility in these muscle groups.
The good news is that most of the things in your Taekwondo class already work on this. You just need to keep at it. Over time, it will improve. The amount of effort you need to put into it depends on your body's condition and your genetics. Some people are just innately more flexible.
Always warm up first. And don't use ballistic stretching. You want to go to your limit, and very gently push past it in a controlled way. You can't do that with ballistic stretches.
I go over stretching more at the following link:
These other answers of mine are also appropriate and worth reading:
You might also look into muscle imbalance. It's not often very well understood, and it does affect flexibility. It's at least something to watch out for. I go over that topic at the following link:
I think not being flexible is something that affects Taekwondo students quite a lot. You see everyone kicking high, and you want to be able to do that. Your instructors will hold focus pads up high and expect you to kick it. If you're unable to kick that high without sacrificing form, balance, and power, you begin to feel like there's something wrong with you. There isn't. You just aren't flexible (yet).
And while they do want you to target up high, understand that it's because they're always pushing the limits. In self-defense, kicking high is usually ill advised for a variety of reasons (not warmed up enough, clothing too tight, too slow, too telegraphed, easy to lose balance and fall, etc.).
Where it might begin to affect your ability to progress in Taekwondo is if you can't score enough points in sparring. Some schools make sure you're scoring consistently higher than students below your rank in order to gain rank. And in Taekwondo, higher kicks often have higher point counts. But don't worry too much about that just yet. It will come in time. And schools generally award higher rank on balance. It's not just sparring that they look at.
Hope that helps.
It is definitely good to be more flexible, as it not only allows you to kick higher in general, but also improves your ability to recover when something goes wrong, such as your kick getting deflected upwards. However, in my opinion, a full split is not necessary since you should be able to kick most targets without having to stretch that far. Splits are more a stunt than anything else, although it is one that most people can achieve within a few weeks of consistent practice (I'll admit that I haven't been able to do them for a few decades because I haven't put that practice in).
As a slight scope challenge, I think that dynamic flexibility is the more important part of training. Splits tend to be more static, especially initially, but where you need to have flexibility is during the movement, especially being able to maintain your stretch against the resistance of your bodyweight shifting, against impact on a successful kick, and to adjust on a miss or deflection. Most of the static stretches can be done dynamically simply by doing them as a movement. Just be careful to not push yourself too far past your limits by throwing your weight into it. Every movement should be as controlled as you can make it, particularly since you will have to learn to maintain your control on impact, so you can't just loosen up the leg, swing, and hope for the best.