Katie Ledecky rules the pool on Day 2 of U.S. Olympic Swimming Trials

Katie Ledecky ruled the pool on the second night of the U.S. Olympic Swimming Trials in Omaha.

On the second night of the U.S. Olympic Swimming Trials, the world’s most dominant swimmer danced with the world record line, several more first-timers booked their tickets to Rio and a decorated veteran left us all wondering.

A few thoughts from Monday's action in Omaha:

1. Phenom Katie Ledecky continues to display her dominance

This is Ledecky’s world, and we’re all just living in it. In Tuesday’s 400-meter free final, Ledecky blasted out of the blocks, bringing the crowd in the CenturyLink Center to its feet as she powered through the first half of the race in 1:56.28, two seconds under (her own) world record pace. Though she calmed down a bit in the second half, the 19-year-old hit the wall in 3:58.98 for the third-fastest swim ever in that event and less than a second off the WR of 3:58.37.

Win No. 1 for Katie Ledecky at the US Olympic trials. (There are likely to be more.) pic.twitter.com/DcscSQ7RNC

— Christine Brennan (@cbrennansports) June 28, 2016

Ledecky’s dominance can be hard to wrap your head around at times. She’s swum in 15 major international finals and has never lost a single one, and she’s broken 11 world records in four years. Talking to NBC’s Michele Tafoya on the pool deck after the race, she said her coach gave her no advice, just told her to go. And it makes sense—the 400-meter event is practically a sprint for Ledecky, whose best events are the 800-meters, which she’ll swim later this week, and the 1500-meters, which isn't contested by women at the Olympics.

• Breaking down Day 1 of the U.S. Olympic Swimming Trials 

Ledecky brings the show wherever she swims, and there was just one other swimmer who was able to remotely keep up on Monday.

Two laps into the 16-lap contest, Ledecky had already pulled ahead of her competition by a body length, but Virginia’s Leah Smith hung with her through the race and brought a powerful closing burst as Ledecky felt the impact of her early aggression. Smith touched the wall in a personal-best 4:00.65, clocking the second-fastest time of the year in the event (behind Ledecky, of course). There’s no doubt that these two swimmers will be favored to medal in Rio.

In regards to her performance, Smith told Tafoya after the race, “I saw [Ledecky’s] feet, so that was pretty cool.” Such is life racing against Ledecky.

•​​ How Katie Ledecky became the world’s most dominant swimmer

2. A groin injury could thwart Ryan Lochte’s efforts to qualify for Rio.

Lochte, who swam the prelims and the semifinals for the 200-meter free on Day 2, is fifth heading into Tuesday night’s final, but it’s not going to be easy to make the team in this event, especially going up against the speedy Conor Dwyer. According to reports out of Omaha, Lochte’s groin injury is still bothering him significantly, to the point where he needed an anti-inflammatory shot just a few hours before his race.

Lochte’s situation is yet another reminder of how, despite the hours and hours of training swimmers partake in over the course of four years, it all comes down to just a few minutes of racing at the trials. They need to be ready if something goes wrong, whether it be broken goggles behind the blocks, bad weather (remember the heat of the outdoor pool at the Athens Games?) or a surprise injury.

A groin strain can be especially disastrous for someone like Lochte, who has a very aggressive push off the wall and underwater kick. Lochte’s limited if that aspect of his stroke is compromised.

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3. Missy Franklin out to a slow start in 2016 trials.

Amid all the hype around Ledecky, Missy Franklin, the four-time gold medalist in 2012, has somewhat faded into the background. Franklin is seventh going into Tuesday’s 100-meter backstroke final, an event she won the gold for in London by only a few milliseconds.

Franklin has experienced plenty of ups and downs since her golden swims in London, and she hasn’t quite been herself. She swam at Cal-Berkeley for two years, then left to turn pro and focus on making the 2016 Olympic team. Franklin also struggled with a back injury, which impacts her underwater butterfly kicks coming in and out of the turns.

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While she may not be dazzling out of the blocks, Franklin still has three other events to swim this week.

4. Patience pays off for the newest American record holder.

Kevin Cordes, who quietly had one of the most head-turning days on Sunday, can finally call himself a member of Team USA. After finishing third in the 100-meter breaststroke in 2012, Cordes won the event Monday, with another first-time Olympian Cody Miller finishing second.

Cordes never excelled on the international level until he broke through at the world championships in Kazan last year, where the breaststroker won silver in this event and contributed to the gold-medal-winning 4x100 medley relay. Now, it appears that he’s banished his demons, and he'll be heading to Rio.

5. Louisville finally has an Olympic swimmer in Kelsi Worrell.

From the starting horn, there was never any question as to which two swimmers were going to represent the U.S. in Rio in the women’s 100-meter butterfly. Worrell and Dana Vollmer led from start to finish, and the two-time defending NCAA champion in the 100- and 200-yard fly upset Vollmer, the defending Olympic gold medalist in this event, to claim her spot on Team USA.