Next time you're shooting a game try this trick.
Keep your eye on the viewfinder. Don't look up to see what's going on. Instead just zoom out while looking through the viewfinder. It works great with the 70-200 lens. Just zoom out, see where you need to go to, then zoom back into that area. The focus will pick-up the new area as well and you'll get more in focus shots as well as more peak moments.
These were all shot at ISO 1600 on the Sony A550 with the 70-200G F2.8.