Triathlete Claire Danson, who won the 30-34 age category at the European Championships in June, has revealed she is paralysed following an accident at the end of August.
Danson - the sister of England and Great Britain hockey player Alex Danson - made the news public on Instagram.
She wrote: "Now I am ready to share my story of the incident that has changed my life forever.
"A story of going from European champion to life in a wheelchair."
She revealed she was involved in a collision with a tractor while riding her bike.
"I suffered two punctured lungs, broke a finger, both wrists, the head of my humerus and both shoulders," she added.
"I also fractured all the bones in my neck, including a break to one, and had multiple fractures and breaks to every one of my ribs.
"I have had quite a few surgeries to sort all this and now have a large amount of metal in me. All of this will heal fully.
"Unfortunately, I also suffered a complete sever to my spinal cord at T9. This means that I am paralysed from my belly button downwards.
"This is of course not something that will heal.
"Whilst I still have hard moments, I have accepted the situation I am now in and won't be letting it stop me do anything that I want to [including triathlon!]"
She added she was "still exactly the same person" and had decided to share her story as she "would like you to follow me and I would like you to learn all about spinal injuries with me".
Alex Danson won Olympic hockey gold with Great Britain at the 2016 Games in Rio.
She is recovering after suffering a head injury when she banged her head on a concrete wall while laughing at her husband's joke in September 2018.
Talking about her sister, Alex Danson said: "She's the most resilient, hard working and inspiring person you will ever meet.
"Having already overcome many challenges in her life before, I know she will reign a champion of this one too."