Hi, AU 5599.
I agree with Cicopo on this. If you look at how pro photographers shoot sports, including cheerleaders/dancers, they use DSLR's, and they use the eyepiece. Never using Live View on the back LCD.
The reason is that you use 3 points to steady the camera: 1.) left hand, 2.) right hand, and 3.) your face. It is all about keeping the camera still and avoiding camera shake. This is even more important using heavier cameras and lenses like DSLR's, which are a lot bulkier and harder to keep steady than a little powershot.
In addition to using the 3 points, you also want to keep your arms and your elbows braced up against your body. Think how hard it would be to write neatly on a sheet of lined paper if it were taped to a wall, and you were writing at full extended arm's length, holding the pen with your fingertips, without resting your hand against the wall for stability.
Think of other examples. You will see a lot of stools with 3 legs, but none with two. 
When you are shooting with the eyepiece, you can sometimes lose track of where the action is when things are moving around while you are zoomed in. For that reason, you should keep both eyes open when needed, not just the one on the viewfinder. You can keep track of the "big picture" with your free eye when needed, but you compose the shot with your eye on the viewfinder.
It does take some getting used to, though, coming from camera-phones and point & shoot cameras with an LCD screen and no eyepiece.
Good luck!
