New Zealand's double Olympic shot put champion Valerie Adams won't defend her title at this month's World Championships in Beijing.
She said her recovery from shoulder and elbow surgery is taking longer than expected.
Adams announced her decision via social media this morning.
The 30-year-old said, "Today I want to inform you all that I won't be attending the World Championships in Beijing. I have thought about this long and hard and know it's the right thing to do."
"For all those that know me, know how competitive I am and how much I love competing in the black singlet."
"This has been a tough come back but I'm glad I made an attempt this season as it has just boosted my motivation more for the Olympics which has always been the main focus."
"Deep down this is not easy but I'm a realist and know I'm not ready just yet and I still have stuff to work and it's been a challenge since my surgery on my elbow especially as it has/ is taking more time then I thought it would... But that's life and I must roll with the punches and deal to this sucker."
"My right knee also needs some tender loving physical care and that will be attended to as soon as I hit NZ soil.... But all in all I want to take this time to thank you all for the continued belief and support throughout my career especially in the last 10 months."
"No one said it would be easy but I'm a willing participant and will continue to fight and work towards defending my tittle in Rio 2016."
Adams has found it difficult making her comeback post-surgery, finishing fourth at the latest Diamond League meeting in Stockholm.
Struggling for top form since her return just over a month ago, the 30-year-old, four-time world champion could only manage fourth place behind German winner Christina Schwanitz, who threw 20.13 metres.
Adams produced fouls on her last four throws.
The New Zealander, who won Olympic titles in 2008 and 2012, the latter after finishing second only for original winner Nadzeya Ostapchuk to be disqualified for doping, threw a disappointing 18.69m, well below her best of over 21m.
Adams returned to competition on 4 July at the Diamond League meeting in Paris but is yet to taste victory after a pre-surgery winning streak of 56 consecutive victories that dated back to 2010.
The World Championships in Beijing start on 22 August.