Sha'Carri Richardson challenger Shericka Jackson drops from 100m
PARIS -- American world champion Sha'Carri Richardson, who holds the world's top time of 10.71 seconds in the 100 meters this year, will start as thePARIS -- American world champion Sha'Carri Richardson, who holds the world's top time of 10.71 seconds in the 100 meters this year, will start as the