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When Federica Pellegrini trots her statuesque 5-foot-10 frame around the pool deck at the London Olympics, it might be tough for her to keep track of past and present.

The standout Italian swimmer has changed coaches enough times to line each corner of the pool, then there's her ex-boyfriend and still teammate Luca Marin, her current boyfriend and teammate Filippo Magnini, plus her many competitors.

But it's the one person missing that has defined Pellegrini's career over the past three years.

Since her beloved coach Alberto Castagnetti died suddenly in October 2009 following heart surgery, Pellegrini has struggled to replace a man she often referred to as a "second father."

A former Olympic swimmer, Castagnetti was also the head coach of the Italian team.

First, Pellegrini turned to Stefano Morini, Castagnetti's assistant, but that relationship fizzled after a poor performance at the 2010 short-course world championships in Dubai. Morini couldn't match Castagnetti's charisma, and wasn't tough enough for Pellegrini. So she then turned to French coach Philippe Lucas, who once trained her main rival, Laure Manaudou.

Pellegrini and Marin moved to Paris to train under Lucas, a no-nonsense kind of guy known for wearing tank tops and multiple gold chains around his neck. Even though Lucas claims he doesn't speak Italian, the pairing produced strong results as Pellegrini defended both her 200- and 400-meter freestyle titles at the 2011 world championships in Shanghai — making her the first woman to achieve the feat.

However, Lucas refused to follow Pellegrini back to her preferred training base in Verona, leaving her coach-less again.

A brief stint with Federico Bonifacenti ended abruptly when Pellegrini made her discontent with the veteran Italian coach known publicly, and by then Pellegrini had started dating Magnini, a two-time 100 free world champion. So she followed Magnini to Rome and settled in with his coach, Claudio Rosetto, even though Rosetto specializes in sprinting.

"Clearly, after Alberto there were sentiments that went beyond simply sports," Morini told The Associated Press. "Beyond the coach-athlete relationship, they were very close. And even though she already had experience with me — since I was Alberto's assistant — we probably weren't able to create that feeling that you need to work together as a duo. She was still thinking about her previous setup, and I was her first coach after Alberto's death, and I probably wasn't able to get fully in synch with her.

"I remain a great fan of hers, and for the good of Italian swimming I hope she keeps racing faster and faster," Morini added. "She's very determined, very decisive. She makes decisions fairly quickly and if she fully believes in a project she really embraces it."

Rosetto has also experienced the wrath of Pellegrini after she failed to advance from morning heats in the 400 at the European Championships in Debrecen, Hungary, in May.

"Every athlete has one coach in their life that they have a great feeling with. She found one and he died. So a bit of chaos was to be expected," Rosetto said. "She had a very strong relationship with him, both emotionally and technically. I'm also realizing how strong her relationship was with Alberto."

Pellegrini is Italy's most popular female athlete and under constant scrutiny from both mainstream and gossip media. Her manager denied repeated interview requests from The Associated Press.

"She's someone who wants the best out of herself, and she also wants the best out of the people around her," Magnini said.

Rosetto has had to adapt to Pellegrini's special needs, starting with the longer distances she races compared to his other swimmers.

"I've got to spend more hours at the pool now," he said with a smile. "Federica trains well. She doesn't lack motivation. But the field of opponents is larger now. Federica has been at the top for nearly eight years. She won silver in Athens and she's always been there, been on the podium. It's difficult for her to improve on what she's already done."

As a 16-year-old, Pellegrini won a silver medal in the 200 at the 2004 Athens Olympics. Four years later, she won gold in the 200 but settled for fifth in the 400 despite entering as the world-record holder.

While she's unbeaten in the 200 at major events for four years, Pellegrini often has trouble with the 400. She cited a lack of energy in Debrecen, but has also struggled with her nerves in the longer race at times.

"The problem is that the 200 comes more naturally for her," Rosetto said. "She needs to build the 400 more."

However, Pellegrini will also face stiff competition in the 200 in London from American rivals Allison Schmitt and Missy Franklin, plus French standout Camille Muffat.

Schmitt and Muffat are 1-2 in the world rankings this year. In the 400, Rebecca Adlington of Britain will be attempting to defend her title before her home crowd, and Muffat and Schmitt will also be tough to beat.

If Pellegrini is worried, she isn't letting on — even to Magnini.

"We never talk about swimming," he said. "We talk about everything else."