LONDON, July 30 (Xinhua) -- It is unfair to point fingers at Chinese swimmers with doping allegations once they win medals in big events, a senior Chinese anti-doping official said here on Monday.
Sun Yang became the first Chinese man to win Olympic swimming gold medal with victory in the 400m freestyle, and Ye Shiwen captured the women's 400m individual medley title in a world record time of four minutes 28.43 seconds.
Ye's stunning performance raised some suspicions over whether Chinese swimmers turned to banned substances for success.
Jiang Zhixue, the anti-doping chief of China's General Administration of Sport, said these suspicions were not justified.
"The Chinese athletes, including the swimmers, have underwent nearly 100 drug tests since they arrived here," Jiang told Xinhua.
"Many were also tested by the international federations and the British anti-doping agency. I can tell you that so far there was not a single positive case."
Jiang added that China had made huge efforts to crack down on doping, saying the swimming success was down to advanced training method and hard work.
"They've made breakthroughs. I think it's the result of scientific training and sheer hard work," Jiang said.
"I think it is not proper to single Chinese swimmers out once they produce good results. Some people are just biased.
"We never questioned Michael Phelps when he bagged eight gold medals in Beijing," he added.