The “Old Guard” is officially gone. It took a long time as athletes have longer careers than in the past, but it still happens. The athletes that have dominated the world stage since 2004 have finally given way to the new generation of sprinters and hurdlers. When the next championship cycle begins in 2019, there will be a slew of new young athletes taking the podium. Predicting who is always difficult as injuries and the emergence of new talent makes things tenuous at best. Many of this year’s youngsters have an outstanding chance to be on the podium. Following are some athletes to watch in 2019.   Men’s 100 Always…