Ok, well I'm probably in the minority here - but when I shoot sports I usually reduce the number of AF points to 9, put the AF point selector dead center and then shoot wide enough that I can crop for desired composition later.
I've found the advantage to this is that in a cluttered field with multiple things a camera might choose to focus on, all I have to do is put the center of the frame on my point of interest and fire. I'm always far enough way that "tracking" as they move isn't difficult at all, and if I shoot a little wide I can get everything I want in the frame and then crop out what I don't need later.
I'm sure there are folks that have a much different method, but that's what I found works best for me personally.