ISTANBUL

China's Anti-Doping Agency (CHINADA) on Thursday called athletics' doping watchdog to increase testing of American track and fielders after sprinter Erriyon Knighton tested positive for prohibited substance trenbolone.

"If trenbolone is indeed a common contaminant in the United States, CHINADA would like to remind athletes from all over the world, including American athletes, to pay close attention to the meat contamination problem in the country when training and competing there, to strengthen doping risk prevention measures, and to eat meat products with caution," CHINADA said in a statement.

"Otherwise, as the American swimmer Michael Phelps — under the wing of USADA (United States Anti-Doping Agency) — suggested in a recent interview, 'if you test positive, you should never be allowed to come back and compete again, cut and dry'," it added.

Citing a statement by the World Anti-Doping Agency, CHINADA stressed that 31% of US athletes had not been sufficiently tested in the 12 months before the 2020 Tokyo Games.

"In light of the above, we strongly call on the International Testing Agency (ITA) to intensify testing on the U.S. track and field athletes," CHINADA added.

It urged the track and field's anti-doping arm, the Athletics Integrity Unit, to enhance anti-doping oversight in US track and field, mitigate doping risks, and thoroughly investigate related cases.