A controversial IOC sponsorship rule has spurred track and field athletes to form a union. Last Friday the U.S.-based Track and Field Athletes Association—which already counted American runner Bernard Lagat and sprinter Sanya Richards-Ross as members—welcomed international stars, including Jamaican sprinter Usain Bolt, into the fold.

Rule 40 bars athletes from promoting non-Olympic sponsors just before and during the Games. The TFAA plans to fight it while also establishing collective bargaining and securing Olympic prize money. "We don't foresee even discussing things like strikes," union president and U.S. middle-distance runner Khadevis Robinson told ESPN.com. "We want to find more ways for the sport's professionals to make more money, not the opposite of that."