OMAHA, Neb. (AP) Michael Phelps is going for his fifth - and he promises - last Olympics. Katie Ledecky is seeking to extend her dominance. Natalie Coughlin wants to end her career by making history. Ryan Lochte and Missy Franklin are back, too.
The big names and some you have yet to know are in Omaha for the U.S. Olympic swimming trials. The eight-day meet begins Sunday in a temporary pool inside the sold-out CenturyLink Center, where Ledecky burst on the scene four years ago with a victory in the 800-meter freestyle and later a gold medal at the London Games.
''There's more pressure here than at the Olympics, and it's harder here,'' Phelps said.
That's because swimmers have to finish first or second to make the team. Those finishing in the top six of the 100 and 200 freestyles can also qualify. A maximum of 26 men and 26 women can be on the team.
Here are some story lines to follow at the U.S. trials:
- Phelps is trying to become the first man to make five U.S. Olympic teams. He's already the most decorated Olympian in history, with 22 medals, including 18 gold. He won six medals four years ago in London, including four golds, but didn't want to be there. Soon to turn 31, he has since gone to rehab and is committed to living a sober life. His son, Boomer, was born in May and he plans to marry - and retire - after the Rio Games. He's entered in five events at trials - 100 and 200 freestyle, 100 and 200 butterfly and 200 individual medley.
- Ledecky is seconds ahead of her closest competition in the freestyle events. She's entered in five events, including all four freestyles ranging from 100 to 800 meters, and the 400 IM. She has set 11 freestyle world records since 2012. The 19-year-old owns 17 of the top 20 all-time combined performances in the 400 and 800 free. She plans to attend Stanford in the fall.
- Coughlin is going for her fourth Olympic team at age 33. With 12 career medals, she's tied with Jenny Thompson and Dara Torres as the most decorated American woman in Olympic history. Coughlin has won a medal in every Olympic event she has entered during her career. She owns the fastest qualifying time in the 100 backstroke, where she is a two-time Olympic champion and was the first woman to break 1 minute in the event. She's also entered in the 50 free and 100 free, where a top-six finish is likely to guarantee her a spot on the team in a relay.
- Lochte could make his fourth Olympic team at 31. The one-time reality TV star is entered in multiple events, starting with the grueling 400 IM on Sunday. The showcase race for him will be his only head-to-head showdown with Phelps in the 200 IM on Friday.
- Franklin made a splash four years ago, becoming the second American woman to win four golds at a single Olympics. Since then, she swam two years at California, winning individual and team NCAA championships, before leaving school to turn pro. At 21, she's poised to cash in if she makes the team and swims well in Rio. Franklin's times have been slightly slower than four years ago, and she's not the top-ranked swimmer in her main events - the 100 and 200 backstroke and 100 and 200 freestyles. ''I'm going to be ready when I need to be ready, and that's right now,'' she said.
- Maya DiRado is a late-bloomer whose continued improvement could land her on her first - and last - Olympic team at age 23. She plans to retire from swimming this summer no matter what. The married Stanford graduate has a real-world job waiting in September. She's entered in the 200 and 400 IMs, 200 back and 200 free.
- Three open-water swimmers already qualified to compete in the 10-kilometer race in Rio are trying to make the roster for the pool, too. Jordan Wilimovsky, Sean Ryan and Haley Anderson are attempting to become the first Americans to make the Olympics in both disciplines since the 10k made its debut in 2008.