Question for the Sports photographers

[MTalley]

I keep seeing these Canon ads in Shutterbug magazine where they'll show a bazillon photographers on the sidelines all sporting Canon cameras with 400/f2.8L or 600/f4.0L lenses.

Here's what I'm trying to understand. The latest ad shows a bunch of photographers at what looks like field level for the Super Bowl. Given these are fixed focal length lenses, would this not cause a problem depending on the proximity of the action to the photographer?

In other words, when everyone is at the other end of the field, I can see where you'd get full-body photos of the players, but when they're at your end of the field, wouldn't you get mainly just face shots, or head and shoulders?

Which part am I missing here?

[GenEOS]

I shoot a 300mm f2.8 for high school football, which for the most part is a good lens. When the action gets close, i need to swap to a 70-200. This is at a HS field where I have near unlimited access to the sideline, even standing within the team at times.
I have shot one NFL game, so I am no seasoned "pro". But, I did learn a lot about shooting the big boys. I shot a pre-season game of the Texans. I was out amoungst the big guns. Noticed a lot of bigger glass than mine. 400 is the norm. Most are shooting 1D bodies MK1/2... I found myself needing a little more lens. This is because the NFL restricts your shooting position. A lot of time you are on the opposite side of the field from the action, or the action is between the 30 yard lines. Being restricted to the 20/30 yard line leaves you a good distance from the action most of the time. I also noted that some of those guys have assistants with them carrying other lens/camera combos so when they move to a new spot they have the right combo. Others carry their own gear and swap. I was probably the only guy swapping lenses! Most the pros crop really tight and they do it in camera. They have keen eyes for the action and are damned good at capturing it. Also, some of the guys are there on assignment with a group of photogs, they may be assigned to only get shots of one subject and thus only need big long glass...receivers for one thing.... I found it amazing how some of the seasoned pros would sit on the sidelines and BS with one another during play then at just the right moment in action quit chatting and rattle off 15 frames of the play, then go right back to BS'ing... I think it is called experience...I need more.