U.S. Anti-Doping Agency

Mo Farah prepares for final US race while allegations swirl

As he prepares for what could be his final track race on U.S. soil, Mo Farah remains dogged by doping allegations surrounding his team.

The British Olympian will race in the 5,000 meters Saturday at the Prefontaine Classic, the only U.S. stop in the elite Diamond League series.

Farah has said that 2017 will be his last year on the track, with an eye on the World Championships in London this August. The 34-year-old plans to transition after that to marathons.

Farah defended his 5,000- and 10,000-meter titles at the Rio de Janeiro Olympics last August, becoming the first British track and field athlete to win four Olympic gold medals. He was knighted by Queen...