Allyson Felix is defending her decision to not step aside and give training partner Jeneba Tarmoh a spot in the 100 meters at the Olympics after their dead heat at the U.S. trials.

They tied for third in the 100 at Eugene, Oregon, in June; three American women were allowed on the team. USA Track and Field scrambled to come up with a rule to break the tie, eventually settling on a head-to-head sprint. But Tarmoh withdrew, ceding the spot to Felix, who already was assured of racing at the Olympics in the 200.

Asked Tuesday why she didn't let Tarmoh have the 100 berth, Felix called it "an emotional situation" and said she had to consider all the people who helped and supported her.

Heats for the 100 start Friday in London.