The ground shot is one of my personal favorites. I will always shoot from my knees when ever possible for football. You will get the face/eyes more IMO. I will shoot from my belly in the endzone (for actions shots) for TD's, goalline stands, celebrations. But know that once they subject distance him/herself from you, you will get that annoying ground.
My point: You're cropped shot #1is good, but again, not a 5-star. Crop it 3x2. #2 cropped is but I would still crop tighter, cutting through #44 at a ascetically adequate point.
The runner's shot works well, where as the paintballer gets cropped at his back foot (again my opinion). as well as DHMN shot being perfect angle and perfect shot.
your photos are smack on otherwise. I really enjoy your work.

