Usain Bolt  is encouraging  Sha'Carri Richardson  to sing a different tune,  telling  the New York Post he disapproves of her trash-talking, and advising her to focus on training.  "I would tell Sha’Carri to train harder and to be focused and not say too much. … If you talk that big talk you have to back it up," Bolt told the outlet. “Jamaicans were vexed because she was talking a lot of s**t before the actual race, it is just one of those things.” “Jamaicans don’t like when people talk s**t about us because we are a very proud people. So if you talk about us we are gonna want you to back it up. It definitely gave those women the extra push to win," he continued.  Richardson reminded the eight-time  Olympic  gold-medalist of American sprinter Justin Gatlin, who continued to poke at Bolt leading up to their race at the 2016 Olympics in Brazil. Gatlin finished second, with Bolt walking out victorious in the 100-meter final.  "That was my thing with Justin Gatlin — because he's the one...