thanks! the background is blurred as the focus was locked onto the car, and i followed the car with the camera keeping it in the same place in the frame, so with a slower shutter speed the car is still sharp but as im tracking the car the background is blurred. its called panning
yeh it takes some practice, but as its on a race track theres constantly cars going past so you can get snap happy. Usually would use a monopod but i didnt have one at the time.
I like how the backround is out of focus and the car is in focus. (i bet you didnt even mean for that to happen LOL!)