Usually, most sporting events rely heavily on cameras, i.e. to judge what happened in an event. In addition to professional photographers, the Olympics also has automated cameras.  We saw this one that runs on a rail to film athletes running around the track. 

Another example is the automated camera used in critical spots & turns to film the canoe/kayak slalom.  The Hawk-Eye is a camera only used in tennis and cricket to film where the ball hits the ground.  You see it every time the player challenges the line judge's call. (The Hawk-Eye is making its first appearance at the Olympics this year).

There are also cameras that are suspended above the venue and can move back and forth on wires. These take the aerial shots.  In fact, the tallest building on the Olympic Green is the BOB (Beijing Olympic Broadcasting) tower for the moving camera. We saw professional photographers with BOB, POOL and PHOTO vests on. At the diving events, there's even a camera that gets dropped when the divers start, so it can film them going down. The cameraman has to use a pulley to pull the camera back up to the top after each dive.