Mitch,
For shooting fast moving game, I was going to give you some suggestions on the your lens and camera settings.
Turn your lens VR (70-200) on and set it to the restricted distance not full. It will focus faster at distance.
I shoot on CH, the high frame rate. Shoot in 12 bit on the D300, not 14 bit. The D300 cuts its speed in half at 14 bit. That is in the shooting menu, under NEF recording.
Leave Active D-Lighting off.
I set AF-C Priority to focus, so the camera won't fire until focus is achieved. The same for AF-S.
Dynamic AF area at 21 points. The focus point which you set, plus the surrounding 20 points will be used to keep track of the subject. You must keep the subject in that area of the frame and focus first.
I leave focus tracking with lock-on at normal. This relates to the amount of time an object can pass in front of your subject prior to the camera switching focus distance. (example a bush or branch)
AF Point selection at 51, so you can refine more where you want the subject in the frame.
AF-On button is only AF-On. I use this button to start the AF system when initially framing and selecting my point of focus with the selector.
Shutter-release button AE-L is on. Allows a continued half press of the shutter to lock exposure.
AE-L/AF-L button is AE lock (Reset on release) - This allows you lock the exposure with this button and not have the half shutter press change your exposure. This works well when you want to lock exposure on continuous focus mode and then the shutter button only focuses and fires the shot. Once the shot is taken, the exposure lock is gone.
So now for the shot.
Set focus mode to "C" and type to the dynamic area auto focus. The middle setting of the control switch.
Use the AE-L button if you would like to like the exposure prior. Your choice.
Set your camera mode to A, S, P, or M however you want along with the appropriate ISO, aperture, shutter as needed for the mode.
Move your focus point where you want to compose your subject in frame.
Compose your shot. Press the AF-on button or give a half shutter press to start focusing on your subject.
Keep your subject as close to the lit focus point as you can, panning the camera as needed.
Press the shutter to get the shot.
I normally also shoot with a 5.6 or 8.0 aperture on a fast moving subject to keep my DOF covering everything as it moves within the 21 points that we have already selected.
Fairly simple, but I hope that helps on understanding the focus system a little.
Best,
Ray