In a recent sparring practice, one of the practitioners used a jump side kick against the adversary, that was dodging and stepping back from the other attacks.
It was a surprisingly effective move, since it was a quick advance and hard to block.
I was left wondering, we never see jump kicks in sparring competitions. Why is this?
First off, yes, this can be a good move for TKD sparring. It's fast, covers distance, and it's very visible (important if you don't have the money for sensors and rely on judges).
As one of my fellow Capoeira students keeps re-iterating, the moment you leave the ground, you lose control. There's very little you can do to change direction. You are pretty much fully committed. And all it takes is someone blocking, or even advancing at the wrong time, and you're off balance and falling.
Unless the rules have changed since the last time I read them, points are awarded for counterattacks, but you aren't allowed to strike an opponent who's "fallen", so there was at one time a strategy of kicking and then falling over which exposed the sport to much ridicule when video of it started going around. But, as with any sport, there are rules, and the way to win is to be good at playing by the rules.
On one hand, you do not get any more points for a jumping kick than you do for any other kind of kick. However, there are times when a jump is better than a standard kick, you just have to be good at not telegraphing your intentions.
The side kick is a good example. Assuming you decided to throw the side kick instead of any other, then you want to kick with the lead foot - it's closer, quicker, and harder to see coming. You could shift your weight back and throw a standing front leg kick, but that will rob you of distance. The only other alternative is to jump. (Technically, you want to hop or gallop; a jump implies throwing your rear knee forward. That's not what you want, that's too slow and easily countered.)
Now, you did say "jumping side kick", but you didn't mention whether or not a turn was involved. Turns make the kicks more risky (because physically, they strain the ankle and knee; and technically, you're vulnerable to a counter). But the rewards are much higher: you get one or two more points for a turning kick than you do for a non-turning variant. See the rules on points here:
You can find these points listing here in the current World Taekwondo rules, these are published April this year. Jump to page 25, under "Article 12", section "3".
There are a few reasons why jumping can be bad.
When you add these together, a wary opponent will be able to capitalise on you jumping because they have a good idea where you will be and what you will be doing for that entire length of time. A short jump to gain height or distance away is a different matter entirely (and regularly used in Olympic style sparring).
You still see the occasional jump and I will never stop doing them. Its a good test of the opponent's mettle if you throw yourself at them leg first, high in the air; if they flinch the game is up.
