Canon 40D, 17.0mm, 1/250s, f/3.5, ISO: 1000
A great way to make your TKD photos look more dynamic is to change the angle of view away from normal eye height. The photo above of Carolina Dillen doing a pattern is taken with a wide angle lens at floor level. A side-effect of using wide angle up close to someone is that anything near the edges of the image appears stretched, ie her right arm and hand isn't really that long and looks pretty weird.
Canon 40D, 17.0mm, 1/200s, f/4.0, ISO: 1000
Alisa Parker and Amy Reeder in a teathered close contact sparring drill. Taken with the camera on the floor.
Canon 40D, 17.0mm, 1/200s, f/3.5, ISO: 1000
Luke, Chris and Carl wrestling. These wouldn't have nearly the same impact if taken from eye level.