I know very little about most sports, so I will go and watch for the first half and then take pictures in the second half. With any sport knowing it will make it easier to shoot because you know what to expect and when to react. If you have never watched Tae Kwondo it's very interesting. My friend who does said it's like the game chess, the more moves you can anticipate the better you will be at the sport.
Unless you are paying attention it can seem like they are just hugging on the ground like some weirdos. However if you take a closer look you can see them trying to get into position to take them down.. As soon as they see and opportunity to take the opposition down everything happens in a few seconds until they either they are hugging again or one of them losses.