Help w/ problem on focus?

[sgriggs2006]

Hello all,
I am still struggling w/ a lot of throw away bball shots due to what I am perceiving to be, a focus problem. It seems to be the worst when players are moving towards me. I don't know if my camera is having a problem judging distance/focus? I use the continual focus mode as I watch the game through the camera. When a play looks as if its going to turn into something worthy, I'll start tracking the play so the focus locks on as the play progresses.
Is that is what is going on w/ these pictures? These show the worst problem. I have cropped them so the problem is accentuated so keep that in mind (yeah, I have cut some hands/feet/baskets out of the picture, lol).
I have tried high (1600)ISO, w/ max synced shutter 1/320, I have tried ISO800 and higher shutter speeds, I have tried my 50mm f1.4 w/ NO flash....I tend to gravitate to my 80-200 f2.8 so I can be in the stands or off the side of the basket.
In between these shots, I'll get the shots that are bang-on....I just don't know what the difference is. The last shot is from a different game but still have the same problems...I just posted it to show that shot isn't as blurry as the first 3.
I have also posted (previous post) a shot from the same night as the first 3 crummy ones that is a top 5 photo of the season for me. It seems to not have this problem. Frustrated!
cheers,
sue.

[SmartWombat]

I'll leave it to a Nikon user.

With Canon I can say the problem is when following it is very easy for the tiny focus rectangle to end up on something else as I shoot.
I'm concentrating on the action and the framing and I may not even notice where the AF spot is, often it's all down to 'feel' for the shot and I find myself almost defocussed and not watching the details. Just shooting when it looks right and when the pan feels right.
At least that's how it goes when I'm in the zone

I use the additional focus points setting, so that I have one key focus point and the surrounding ones are supplementing the AF. I can track say a driver's helmet and know if I'm slightly off the AI Servo is not going to flip to the background.
I also set the AF speed/sensitivity to low, so that it's not so sensitive to things passing in front of the subject like bits of fencing.

Now I'm typically shooting cars outside, not in a dungeon. So I have a small aperture and a little latitude in the depth of field. For you all the problems are probably worse because you need a large aperture to collect the little light that's out there. So any focus issues are going to be magnified.

Sorry I don't have specific answers for Nikon, but perhaps my Canon settings will spark off some idea how you can tweak your settings.