Franklin aims to 'set new bar' in booking Rio swimming berth

After two years of career doldrums, Missy Franklin has the wind in her sails as she heads into the US Olympic swimming trials in search of a Rio berth.

As effervescent as ever at the age of 21, Franklin was bubbling over with anticipation on Saturday as she pronounced herself "ready to rock on all cylinders".

"This is my goal -- I need to make the Olympic team," Franklin said. "That's what I'm here to do."

Just four years on from her four-gold haul at the 2012 London Games, Franklin's Rio campaign has the flavor of a comeback.

She followed up the 2012 Olympics by winning three individual world titles in 2013.

But back problems hindered her at the 2014 Pan Pacific Championships and she earned just one silver and one bronze in four individual events at the 2015 worlds.

So far this season she's been frustrated with race times slower than she expected, even for competition in the midst of full training.

That's a trend she's aiming to reverse in Omaha.

"I have times that I really think I'm capable of doing this summer, and right now I want to get as close to those times as I possibly can," Franklin said.

"And I'm hoping that gives me a spot on the team."

Out of the pool, Franklin has had to learn to manage the demands that came with turning pro, which she did in 2015 after spending two years swimming for the University of California at Berkeley.

She has returned home to Colorado to live with her parents and reunite with coach Todd Schmitz, and says the move is paying off.

She'll face a typically challenging multi-event programme at the trials -- a schedule that should see her contesting the 200m freestyle semi-finals and 100m backstroke final on Tuesday night.

In the 200m free she can expect stiff competition from Katie Ledecky, the freestyle phenomenon who has been inexorably expanding her range from the distance events to middle distance and even sprint races, and 2012 Olympic gold medallist Allison Schmitt.

In the 100m backstroke she's ranked 13th in the world this year, with two Americans -- Olivia Smoliga and Hannah Stevens -- both boasting faster times.

But Franklin said she isn't worried that her 2016 efforts will be overshadowed by past success.

"I plan on setting a new bar at this meet,? Franklin said. ?That?s kind of almost unrelated to what I did in 2012, because everything is so different."