You don't say which camera you have, so things may vary a little, but you can use continuous shooting with the focus mode set to AIServo . This is how most sport photographers work. The camera will try to predicted a moving subject and refocus in between each shot, and you should get on say a Canon 40D around 5 in focus shot every second.
mr-pants says what I would do and for the same reason (short burst, to avoid someone bilking in your photos.) With the 3 song rule just machine gun away, you'll be surprised how quickly 3 songs go by.
With continuous shooting you camera buffer will fill up, but the camera will not then stop shooting until the buffer is empty, just the frames per second rate will just slow right down as the buffer is emptied (this is the reason to use high speed memory cards) Now depending on what camera you have and if you shoot RAW of Jpegs you'll get varying amounts of shoots and frame rates .
Canon 550D shooting JPRG/Fine at 3.5 fps you'll get 170 shoot before the buffer is full, so 48 seconds of continuous shooting.
Canon 1D IV shooting RAW at 10 fps you fill the buffer at 28 shoots so just 2.8 seconds of continuous shooting.