Double Olympic champion Mo Farah says he is feeling more "upbeat" after his coach Alberto Salazar was embroiled in a doping scandal.
A BBC investigation alleged that American Salazar, who coaches Farah in the United States, has practised doping techniques with other athletes.
"The past week has been tough, but having had time to reflect, I am feeling much more upbeat," said Farah.
There is no suggestion that Farah himself has been involved in doping.
The 32-year-old pulled out of a Diamond League race in Birmingham on Sunday, saying he felt "emotionally and physically drained" by the allegations.
He then flew to the United States to spend time with his family and "seek answers" about the scandal.
Farah added in a message on his Facebook page: "I do realise that at the weekend I disappointed a lot of people by pulling out of the race and I wanted to apologise again to you all and say a massive thanks for your on-going support."
Salazar strenuously denies the allegations made by the BBC and has promised to show that they are based on "false statements".