He doesn't think it's possible, at least at the moment.
He moved into a house with them eight years ago.
A British newspaper hired biomechanics experts to study his recent changes.
The repeat gold medalist is adamant that he's clean.
He will move up to the 26.2-mile distance next spring in London.
The double-Olympic medalist's coach dismisses the doubters.
The Brit grabbed gold in the 5,000m on Friday night.
He says he's better than he was when he won two Olympic gold medals last summer.
He is the man to beat in Moscow.
The decorated Olympians could race over 600 meters in the near future.