The key to good sports photography is cropping. There is very rarely a shot produced by a professional sports photographer that can not benefit from cropping.
Picture 1 could be cropped on the right some
Picture 2 does not need as much water below it
Picture 3 can be cropped from the right
Picture 4 can be cropped from the left
Think the focus is on the players, very rarely is an action shot needing a scene setting. You know they are on a playing field or a pool, you do not need to show it as much, the focus should be on the players.
Everyone complaining about the shadows on the first football shot have never taken photos at a high school field at night, other than a high school gym one of the most challenging places to shoot anything.
Good work, every shot you take will be a learning experience, but remember to crop. I am not a professional but you can see good use of cropping on my site http://www.minnihan.com/