The 2008 Olympic silver medalist and 2009 world champion swimmer was ruled out of China's squad for the London Olympic Games, but said he is still aiming for the 2016 Olympic Games in Brazil.

The Beijing University of Technology student told reporters he will only take part in the Chinese Universiade this year, then try for the National Games and World Championships next year.

"In four years, I think I will get the chance to compete in the Olympics," the 25-year-old Beijing native said. "(Winning an Olympic gold medal) is my dream and I will not give up."

He said he accepts his non-selection due to his slumping form. He failed to make the Olympic A standard in either the 200m or 400m freestyle at a number of Olympic qualifications.

"I had some slim hopes before the National Championships in April," Zhang said. "But the pool results from the National Youth Championships in May killed my chance to swim for the Chinese Olympic squad. Competition in sports is crucial, and I have to accept that fact. I can understand the decision.

"I hope my young teammates will try their best in London and get better results than I did four years ago."

Zhang's coach, Chen Yinghong, cited a litany of reasons for Zhang's performance.

"Zhang's ebb is linked to his mental and physical condition," Chen said. "He was under a lot of pressure — it was a period of ups and downs, especially after his unexpected failure at the Guangzhou Asian Games in 2010. A long period of intense training also bottlenecked his efforts to improve.

"It's normal for an athlete to go through lows and highs, but Zhang is going through a long period of poor form, which is a new thing for us to deal with."

Chen believes Zhang is a strong-minded swimmer who never thought about quitting.

"He is a tough man," Chen said. "He keeps swimming for his dream and will not give up even if he's in a very difficult situation."

Zhang said he wishes it hadn't come to this.

"I'm sorry I disappointed my fans," he said. "It's a shame I cannot fight for my country this time. But I'll never give up, and I'll be back."

Beijing swim team manager Liu Xunlan echoed Chen, saying Zhang's setback is temporary.

"Zhang won national titles in all distances from the 200m to 1,500m freestyle when he was 17, and he won a silver medal in the 400 freestyle at the Beijing Olympic Games in 2008, China’s first-ever Olympic medal won by a male swimmer," Liu said.

"In addition, he became China's first male swimming world champion during the Rome World Championships in 2009. He is one of the best swimmers in the Beijing swimming team's history. We are facing a hard time, but it is temporary. He'll keep swimming. I'm looking forward to his comeback and impressive games again in the future."