Australian Olympic champion Sally Pearson announced on Wednesday she had split with her coach of 14 years, Sharon Hannan, saying the time was right to part ways.
"Sharon has made me into a champion but I feel that to move to another level I need to freshen up my approach to training, develop fresh ideas and incorporate new challenges into the way I do business," Pearson said.
"My competitors are always striving to make themselves better and I must do the same."
Pearson, who won gold at the 2012 London Games in the 100m hurdles, said in a statement that Hannan had been "an amazing coach" and she would continue to attribute her success to her.
Coach Hannan, under whom the 27-year-old Pearson won silver in the 100m hurdles at this year's world titles in Moscow after two serious hamstring injuries, said she was disappointed.
"But Sally and I discussed the options and she believes this is best for her," said Hannan in the same statement.
"We had some amazing performances. We have conquered the world and I wish her every success for the future."