It's common for coaches to video tape athletes, so both can examine the style and progress of training.
The son of a friend is into the Triple Jump, and he took the process a step further. He used a digital camera to video tape his son doing the triple jump about ten times in a row. In this case, he borrowed my Samsung NV-3 digital camera, which records movies at 720x480 at 20fps or 640x480 at 30fps.
("How long a movie can this take?" asked my friend. About 1.5 hours on the 2GB memory card.)
By using the digital camera instead of a movie camera, he could immediately copy the video file onto his computer, and then go through the jumps frame by frame.
("How do I get the movie file onto my computer?" asked my friend. Take the memory card out of the camera, and plug it into this USB memory card reader. That's easier that using the camera's cable and having to install camera-specific software.)
Next, he went to YouTube, and downloaded videos of famous triple jumpers, such as Jonathan Edwards. He compared his jump style with those of the famous ones.
This seems so normal today, and we tend to forget that this was not possible just a few years ago -- when digital cameras did not have DV-quality movie recording, and YouTube didn't exist with its rich resource of scholarly information.
My friend returned the camera the next day, enthused. "It worked really well." The only negative, which I had warned him about, was that the NV3's screen is not particularly bright outdoors. He agreed: "Even through it was an overcast day, we had to hold the camera inside my coat for viewing. People must have been wondering what we were doing in my coat!"