I never use IS during sports photography. Since I use a monopod and have a pretty steady setup, and never shoot below 1/1250s, I don't really need it. I also have no OOF shots, or at least very rarely. There's no reason for me to constantly run the IS motor when it makes not a lick of difference in the quality of my photos.
However, when handholding at slower shutter speeds, I definitely use it.