US sprinter breaks Bolt's record of most world c'ship medals

American sprinter Allyson Felix has become the most decorated athlete in world championships with 15 medals, breaking Usain Bolt's shared all-time record of most medals at the biennial athletics event. The 31-year-old American won women's 4x100 metre relay on Saturday to claim her career's 10th world championship gold medal, which is also an all-time record among female athletes.