Swimming: Missy Franklin swims year-best time of 58.67sec for 100m backstroke

LOS ANGELES (Reuters) - Olympic champion Missy Franklin clinched her fourth title when she swam the fastest time of the year to win the women's 100m backstroke at the United States National Championships on Friday.

The Indiana meeting is doubling as trials for the world championships in Barcelona from July 28-Aug 4.

Franklin, who came from behind at the turn to beat Elizabeth Pelton in 58.67sec, had already qualified in the 100 and 200 freestyle, the 200 back and earned a place in both the 4x100 and 4x200 free relay squads.

"I think the whole field was right there at the 50,"Franklin said after she pipped her future collegiate team mate Pelton by 0.6sec.

"I knew I had to bring it back that last half, so it was tough. It hurt a lot. It's the hardest, but that's my favourite part that last 15 metres."

Despite being the quickest in the world this year, the 18-year-old said she was looking for more improvement before the world championships.

"The main goal is to be faster in four weeks than we were right now," Franklin said.

"I think that's the goal for everyone. It will definitely be about the little technicalities the next four weeks."

Fellow Olympic champion Katie Ledecky claimed the women's 400 freestyle with Chloe Sutton second. while Connor Jaeger won the men's title with Matt McLean second.