Running Shoes vs. Cross-Trainers: Which Do You Need?

... longer and fit a variety of foot types.) Opt for cross-trainers if: Your workout routine involves aerobics, weight training, or group classes like kickboxing. If you're moving side-to-side at all, get cross-trainers.

http://simplystated.realsimple.com/2013/04/03/find-the-right-shoe-for-your-workout/