Burundi's Francine Niyonsaba will miss the World Championships in Eugene, Oregon after failing to recover from a stress fracture in time for the competition, where she was set to participate in the 5,000m and 10,000m events.
"Me and my team we did everything possible to recover," Niyonsaba wrote on Instagram on Monday. "I am almost OK now but I couldn't train for all this period, so I'm not in the shape ... to perform the way I wanted."
Niyonsaba, 800m silver medallist at the 2016 Olympics, is not allowed to compete at her preferred distance because of naturally high levels of testosterone. She moved up to the 5,000m at Tokyo but was disqualified for a lane infringement.
The 29-year-old won the 5,000m at Diamond League meetings in Zurich and Brussels last year, and also set a 2,000m world record in Zagreb.