Karate - A Sidekick Jump

It's because karate, kung fu, and other martial arts not seen in UFC and other tournaments simply aren't practical. Those martial arts were developed at a time when the people developing them were isolated. They came up with what they believed to be the most effective way to fight. This was actually true, while the people developing the arts were still isolated from one another. However, as people across the world began to become more globally-aware, martial arts were compared and mixed, and that brings us to today: where the martial arts seen as effective are truly the best in the world. Of course, the ideal martial art varies from person to person, but kung fu is almost always inferior against something used much more often today, like boxing (when comparing two identical people, that is). For the record, I have about ten years' combined experience in Goju Ryu karate, a couple forms of kung fu, and kickboxing. I love them all, but kung fu is definitely the least realistic of the three.

How come you never see anything like this in the UFC tournaments? If Karate, or Kung Fu, or any of the other systems are so great, why are they consistently losers in the UFC? Is it because the real masters aren't competing?

Agree with Eric. Also about karate, shouldn't you be starting with the proper stance, like what your partner's doing?

beutiful kick

This is not a jump sidekick, it's a hop sidekick. Your base foot has to be in the air, and his is on the ground as he kicks. And another thing, if you do the step first like he says before the hop, you telegraph the technique and the other person knows something is coming.