Shooting college football (with relatively unlimited access to the sidelines) really is a kick and a half. Having shot for the Santa Ana College Dons for over 5 years, I have a feel for the next play which gives me a chance to get in position. I'll actually walk/run over a mile during a game. I noticed some of the other photographers lagging behind me, even though they are much younger.
My biggest problem shooting football is with my equipment. It looks pretty good but is not the top end equipment used by the pros. I really don't want to buy a new $6,000 DSLR body that will drop to $1,000 in the next couple years. I've already made that mistake twice with the D2H and D2X. Also, shooting from the sidelines requires a wide range telephoto zoom to maximize the different photo opportunities at different distances. It's not like the NFL where there are dozens of photographers on the field using different length telephotos from different distances. Nikon only offers one telephoto zoom, an 80-400, but it utilizes a slow screw focus mechanism which simply isn't adequate for fast action football. It is great for surf photography though.
So I had to go "different" from an equipment perspective. I had been using the very sharp and fast Sony 70-400 with an out-of-production A580, 16 MP body with optical finder. Right before the first football game of the season, Sony introduced the A57, and 16 MP body with electronic view finder (EVF) that can shoot at 10 FPS with the lens at maximum aperture. Shooting at 10 FPS is a whole different experience. Now I want 12 FPS, which the A57 will accomplish at 8 MP. Amazing, and the body is only $600. Yes, the EVF lacks the clarity and speed of an OVF but shooting a runner piling through the front line is really a "spray and pray" operation anyway. You don't have time to manually focus. For this purpose, the A57 fits the bill for this purpose nicely.
This brings me to a comment on shooting style. I'm really lazy. Most serious amateur photographers will purchase the most expensive body they can afford and use all their lenses on that body. I actually don't do this. I own an assortment of body and lens combinations, each used specifically for a different purpose. With the quick obsolescence of camera bodies, this is easy to do since I keep all my old bodies. As mentioned above, the A57 with 70-400 is ideal for my football photography. An old D300 with 300-800 is fantastic for surf photography. A D800 with 200-400 is outstanding for close-up flower photography. A D7000 with Sigma 17-70 OS macro allows me to be creative with its close focus of only 8 inches. Finally, another D7000 with Sigma 8-16 provides me with a wide angle perspective not available by any other camera or lens manufacturer.
I generally carry several combos with me depending on the type of shooting I will be performing. When I visualize an image in the field, I just reach in my bag and grab a combo. I very seldom change lenses in the field.
The above image shot was taken with a cropped frame, 16 MP DSLT 70-400 F4 zoom lens at 10 FPS hand held.