Olympic champions Ryan Lochte and Missy Franklin headline the US swimming championships that start Tuesday, when a bevy of youngsters will also try to break onto the international scene. Franklin, still just 18, is already an established star after winning the 100m and 200m backstrokes and two relay gold medals in London along with a relay bronze. The irrepressible teen is entered in six events in the championships, which serve as the trials for the FINA World Championships in Barcelona on July 19-August 4. The top two finishers in most events book world championships berths, although in the non-Olympic events of 50m backstroke, breaststroke and butterfly and the men\'s 800m free and women\'s 1,500m free, only the winners punch their tickets to Barcelona.Franklin is seeded first in the 100m freestyle, second in the 200m free behind Olympic gold medallist Allison Schmitt, on top in the trio of backstroke races (50, 100, 200) and is also entered in the 200m individual medley. The 200m IM marks a departure for Franklin, although she finished second behind Caitlin Leverenz in the event at the Santa Clara Grand Prix on June 2. The post-Olympic year, before she launches her collegiate competitive career, could be a good opportunity for Franklin to experiment. Franklin won the 100m and 200m backstrokes and two relay gold medals in London, along with a relay bronze. Lochte, whose five medals in London included two golds and took his career tally to 11 Olympic medals, spent some time after the 2012 Games basking in celebrity, filming his reality television show and popping up regularly in the gossip columns.But Lochte has returned to his famously fierce training routine and put his name down for the demanding 400m individual medley in Indianapolis. Lochte won gold in the 400 IM in London, his time the second-fastest in history. With world record-holder Michael Phelps out of the picture, it\'s now up to Lochte to hold off such challengers as Tyler Clary, Conor Dwyer and North Baltimore Aquatic Club product Chase Kalisz. Lochte, who has been known to shift his schedule abruptly after entering multiple events, is also entered in the 200m freestyle and 200m backstroke, 50m and 100m butterfly and 200m medley. Katie Ledecky, the 16-year-old who broke British hearts with her victory in the 800m free in London as home hope Rebecca Adlington finished third, is entered in the 200m, 400m, 800m and 1,500m freestyles, although the longer distances appear to be her best bet both at trials and in Barcelona. Other 2012 individual Olympic gold medallists slated to compete include Clary, who won 200m backstroke gold in London ahead of Ryosuke Irie and Lochte, plus Nathan Adrian, Matt Grevers and Dana Vollmer. From: AFP