I would say it’s flexibility training. Most people don’t realize this because their primary goal is to look good. But fitness is about how you feel as well. And the more flexible you are, the better you feel. And you will look better.
Flexibility refers to the ability of joint and surrounding ligaments to move through a range of motions without causing any pain. The first benefit of a more flexible body is that it will improve your daily functional abilities such as walking faster and bending more easily.
Secondly, it will improve your posture. As you become more flexible, you subconsciously stretch out your muscles and extend your bones to open up your chest and back. Ever wondered why ballerinas look so sophisticated? It's because they always keep their chest up and head high.
Last but not least, it will improve your athletic performance! Since your muscles can move in a broader range of motions, they can protect you from injuries. So you will be able to lift heavier, jump further, and run faster. It also takes less time for your muscles to recover after an intense workout.
Now, the question is how to improve your flexibility?
The simplest approach is to never skip stretching. People always ask me if you a dancer in the gym when they see me do splits. I’m not, and all it takes to do splits is doing the same stretching movements every day for a certain time. I would put my emphasis on the hamstrings (the back of your upper legs) because they are mostly overlooked and they are the keys to do splits.