Aye its one area where you can get away with a smaller aperture lens; however I don't know if you do any work like this in darker conditions, at night or are thinking of doing any other sports or events which might warrant a wider maximum aperture lens as an option.
If you want a zoom the 100-400mm would be an ideal choice if the new MII version fits into your budget. The older version is cheaper, but was a solid performer, but with some drawbacks. Some people loved it others disliked it - it was and still is a very fine lens, but not always as tack-sharp as some wanted it to be. It's also quite old now (lens wise) and the new version is streets ahead of it.
A 70-200mm with 1.4 TC is another option, like I mentioned above, and 70-200mm is often a very solid "catch all" lens for many genres and quite adaptable. Many photographers can make use of one or will use primes that cover a similar rough range of focal lengths.