yep stretch, stretch, stretch.
A good roundhouse kick is an excellent offensive weapon. Because the primary target is about 30 degrees short of dead center, it can be a tactical surprise strike. Stretching is the obvious solution. You should also work on perfecting your technique. The kicking foot should come up, knee first, as high as you can get it, as in a front snap kick. Starting from this position helps you get the kick higher. The planted foot must rotate so that the heel faces the target. If this is done at the same instant that contact is made, you get a very powerful strike.
There are actually two elements to a good high kick. One is flexibility to be able to stretch your hips like that. The other is the strength to pull up the weight of your leg. I can't say which is the issue with you. It might be a bit of both.
Splits stretching would improve your flexibility but even if you could sit in splits you might still not be able to kick high without a strong enough core and hip flexors. Doing standing leg lifts can help improve your strength for high kicks.
Stretching and practicing are the only way.
FYI, I would ask you why this is important but I'm not a sports focused martial artist. I will tell you that if you tried to do this against someone who knows what they're doing you're going to be in a lot of trouble. So keep in mind that flashy kicks look cool they aren't very effective against someone who knows how to fight well.
Look up how Mirko CroCrop extended his,, yes you should stretch, but also work out that leg(s) as much as possible because it won't be as used to traveling higher/further distances if you work out your leg you will obviously be able to kick further and more powerful,, without the extra strength your kick will stop where your used to kicking, which is lower.... Also kick higher more, which I mean by that recreate your fast twitch muscle fibers to get used to kicking higher.
Do it slow right and a thousands times then try with abit of power and go from there. I here tkd guys would think different I would not like to meet a well trained one. They can punch elbow and clinch just as well. They do groundwork that is pretty ok. The art itself is worse for real self defence than the heavy styles of ju jitsu and karte. But for hand to hand combat no weapons its one of the better ones.
I can kick at about the hight of my head but my leg isn't fully extended. Is there a simple way to fix this? Should I just stretch?
