OMAHA—Niall Janney breathed heavily as he floated toward the pool wall.  He had just completed one of swimming’s most physically-demanding races, the 200-meter butterfly. It wasn’t Janney’s best performance, but it was a special one.

Twenty-seven Harvard-affiliated swimmers are competing in the U.S. Olympic Trials this week at CenturyLink Center in Omaha, Neb. Among these swimmers are thirteen returning student-athletes and eight recruits. In addition, four swimmers from the Class of 2012 will be swimming their last races for the Crimson: Niall Janney, Meghan Leddy, Hilary Roberts, and Catherine Zagroba.

On the third day of Trials on Wednesday, Janney swam nearly three seconds slower than his best time in the 200 butterfly, finishing 123rd in a 139-swimmer field. But he walked away from the pool content, having concluded his career on one of swimming’s grandest stages.

“It was a little bit of a disappointing swim for me personally, but it’s a terrific feeling being able to finish off my career here at Trials with my teammates,” Janney said. “I couldn’t be happier representing Harvard in my last swim; it feels really good.”

Yesterday, Catherine Zagroba also wrapped up her career with the Crimson with a 73rd-place finish in the 400 freestyle. She looks forward to following the women’s team next year as she works in Boston.

“It just means so much to be here with all the Harvard girls,” said Zagroba after her race. “I wouldn’t be here without all of their support.”

Through the first three days of Olympic Trials, Harvard swimmers and recruits have accounted for 24 individual swims in 10 different events. Rising sophomore Courtney Otto has led the Crimson with a 22nd-place finish in the 200 individual medley.

“I was happy with the swim,” said Otto. “I was really trying to work on my backstroke and breaststroke legs; I tried to speed up my tempo in those strokes.”

Otto, who represented Harvard at the NCAA Championships this spring, dropped nearly two seconds from her previous best time and narrowly missed the top-16 semifinal round. She looks forward to competing in her best event, the 200 butterfly, tomorrow.

On the men’s side, rising sophomore Chuck Katis turned in a 37th-place finish in the 100 breaststroke on the first day of competition. Katis broke school records in the 100- and 200-yard breaststrokes in his debut collegiate season earlier this year.

“The whole race felt great, though I think I tightened up a little bit at the end,” said Katis, who will swim the 200 breaststroke tomorrow and the 200 individual medley on Friday.

While the Trials represent a final farewell for graduated Harvard swimmers, it also provides a first look at important new additions to the men’s and women’s programs. Trials competitors Steven Kekacs, Christian Yeager, Jacob Luna, Christian Carbone, and Tyler Rocca will join the men’s team next year as members of the Class of 2016. Margaret Ramsey, Kendall Crawford, and Connie Hsu will join the women’s.

“[The men’s team] did really well this year, but with our recruiting class, we’ll be really strong,” said Kekacs. “It should be a good match-up between us and Princeton at Ivies.”

The Harvard men placed a close second to Princeton at the 2012 Ivy League Championships in March.

“I’m looking forward to them coming in and producing a whole new dynamic for the team,” Otto said of the women’s recruits.