China's Olympic medical chief has warned the country's coaches not to train their athletes into the ground after a spate of injuries to Beijing 2008 medal hopefuls, state media reported on Wednesday.

Heavy training and competition schedules had "stalled" careers of a growing list of athletes, Li Guopeng, chief medical officer of the Chinese Olympic Committee, told the China Daily.

"Excessive and intensive training is not good for our athletes," Li said.

"Our coaches have to work out a more scientific training plan, which should be more relaxed but more efficient."

Li said former Wimbledon and Australian Open doubles champion Zheng Jie had carried a "painful" ankle injury at the recently concluded French Open, which had caused her to lose in the first rounds of both the singles and doubles at Roland Garros.

"When Zheng had just got injured I told her to have a good rest and wait for a full recovery but she was too anxious to practise and play," he said.

Heavy training had also lead to injuries to the national women's volleyball stalwarts, Feng Kun and Zhao Ruirui, and a number of younger players, Li said.

"Since the competition within the team is so fierce, most of them insist on training and competing despite their injuries, which will do harm to their future career and health," he said.