CC and suggestions please

I like to shoot sports and I feel they turn out ok but I'd like to take it up a lot. I shoot in AV mode with a 40d, 70-200 2.8L, on a monopod. I try to keep it 1/2500 -3000 if possible. What can you guys suggest to make these better? All of these are cropped as the fence is a fair distance from the field. Any other info that would be helpful just let me know.

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It looks like the focus is off on all of these photos.
First thing to know is that excessive cropping will show errors in focusing.
Shoot tight and then crop.
Try shooting at f5.6 or higher. If still soft then it is time to have the lens and body adjusted to one another.

If you don't already, sit down for sports shooting. I don't think a monopod is needed for a 70-200 but thAts a personal choice.

Thanks for the suggestions. These are shot at 200 so that's as tight as I can get with the access I have. For football I do sit down. With the 4 foot fence it's hard here. I tried the mono pod for the first time this weekend to see if it would help in the final product. No difference but my neck sure felt better after the weekend. Lol

We have more games tomorrow so I'll try it at f5.6. If the access is better I'll try to get closer as well.

Thanks!