South Korean electronics company walks away from the IAAF.
Double world gold medalist Vivian Cheruiyot wins the 5000m.
There were numerous world-class performances on the track Friday.
Check out these photos of some of the world's top track & field athletes before Thursday night's meeting in Switzerland.
Some of the best middle-distance runners in the world will be there.
American Khadevis Robinson pulls off upset win in men's 800 meters.