Former world champion Manon Carpenter has quit downhill mountain biking at the age of 24 after becoming "more aware of the consequences of crashing".
The Welsh rider won the 2014 World Championships and World Cup series and joined the Radon team in January.
"I just didn't want to take the risks involved with racing at 100% any more," Carpenter said.
"Racing downhill is gnarly and you have to have the confidence to commit to whatever is put in front of you."
Carpenter said she has been considering her future for some time but only reached a decision during the national championships last weekend.
"Over the races this year I've been finding it harder to face up to difficult situations and I came to the conclusion I just didn't want to take the risks any more," she said.
"As much as I've tried to put this out of my head, it's stopped me from enjoying racing as I would like to.
"I quickly realised that World Cup racing isn't something I should force myself into if my head isn't in it."
In 2011, Carpenter, from Caerphilly, won the Junior World Championship and World Cup series overall.
And during her dominant 2014 season, she won three World Cup series events and finished second behind Rachel Atherton in the overall series in 2015 and 2016.
"Racing on the World Cup circuit has been an amazing and unexpected opportunity for me," said Carpenter.
"There have been some huge highlights and I feel like I've given as much as I had.
"Now I'm looking forward to having time to enjoy riding at home and to see what else there is for me to do."