Swimming preview: China's Sun expects to retain 400m and 1500m free titles, Phelps still biggest star in pool

The Chinese swimming team will not expect to collect as many titles as they did four years ago while they put a younger generation of swimmers to test at the Rio Olympic Games.

The team posted the best ever result in London Games where they bagged five gold medals, two silver medals and three bronze medals. In Rio, the 43-member squad will again rely on world and Olympic champion Sun Yang but his road to glory seems bumpy.

The 25-year-old looks to defend his 400m and 1,500m freestyle titles in Rio while also swimming in 200m free after he recovered from a foot injury.

Sun, 1,500m free world record holder, will probably be challenged in his trademark event as Italy's Gregorio Paltrinieri, 21, was only 3.02 seconds shy of Sun's world record when he won the European Championship this year.

He will also meet his old rival Park Tai-hwan after the South Korean star, Beijing Games 400m free winner, won an appeal to the Court of Arbitration of Sport against South Korean Olympic Committee's ban on his participation in the Games.

Although double Olympic champion Ye Shiwen is not as strong as she was four years ago, China can stake their hope on new sensation and world 100m freestyle champion Ning Zetao.

Ning, who is making Olympic debut, will chase the 100m free title while he is chased by hundreds of thousands of fans outside the swimming pool.

Zhang Yufei, Liu Xiang and Shen Duo, all under 20, are not the top in their respective events but expected to make an impression in the women's field.

As usual, the United States remains the power in the pool, spearheaded by five-time Olympian Michael Phelps with 18 golds and 22 medals overall.

The U.S. team also boasts teen sensation Kate Ledecky, who is one of the world's most dominant swimmers at age 19. She is the world record holder and huge favorite in both the 400m and 800m free, and could bring home another gold in the 200m free. In addition, she will anchor the 4x200m free relay for the Americans, making them the team to beat.

One strong opponent the American team has to face is Australia, who took just one gold in London but announced their return to the top at last year's Kazan world championships with seven gold and 16 medals overall. In the team, sisters Cate and Bronte Campbell lead the way, along with Emily Seebohm and Mitch Larkin.

Russia was hit hard this time as FINA announced a ban on seven Russian swimmers due to doping cases, including star swimmer Vladimir Morozov and Yuliya Efimova.

Brazil, the host team, fielded its largest swimming squad ever but its biggest star Cesar Cielo stunningly failed to qualify at the Brazilian trials.

All the swimmers have to deal with late night finals. In Rio, the prelims have been moved back to 1 p.m. local time, while the finals won't begin until 10 p.m. -- both about three hours later than most meets. Endit