Long sprinters should run cross country to assist in developing their aerobic base. And it is confirmed by all the Georgia coaches that you will not destroy fast twitch by letting your long sprinters train at longer distances (over-distance training). Most high school sprinters would benefit from cross country.

Is distance running bad for sprinters?

Q: How does long distance running affect sprinters? Does it really improve and build endurance; does it damage or alter fast twitch muscles? A: The short answer is that it will probably assist your cardiovascular system, but won't do a lot for your fast twitch muscles.

Do you have to run fast in cross country?

The ability to run far is essential. So is the ability to run fast. To be good at cross country requires running pretty fast for a pretty long time. Most cross country races are between two and five miles in the US, though they can be as long as 12K (7.4 miles) at the elite level.