Chris Froome says critics who have called on him to retire "make me laugh" and insists he is not "just going to throw in the towel".
Froome, 35, has been battling to return to full fitness after suffering serious injuries at the Criterium du Dauphine in 2019.
The four-time Tour de France winner has been dropped on several stages over the last few months and is yet to show that he is near his best level again.
Vuelta a España
'Predictable Ineos have a great opportunity to attack' - Blythe
However, in a YouTube video titled "Chris Hits Back", he says he has no plans to stop after working his way back this far.
"Over the last couple of races people said: 'Hang up your bike, you're done, you're finished'. It just makes me laugh - those people don't know how bad my injuries were.
They don't know how far I have come to get back to professional racing. They clearly don't know me as a person - I'm not just going to hang it up. I know I can get there.
Froome, who switched from Ineos Grenadiers to Israel Start-Up Nation at the end of 2020, will not ride the Giro d'Italia this month as he targets a fifth title at the Tour de France instead.
He admits he still has a "lot of work to do" if he is going to win a Grand Tour again, but is spurred on by criticism.
"Even though I haven’t been showing much up front, I really feel that the intensity of being in the peloton is really helping me. Being in the wheels and in the bunch is beginning to feel a bit easier.
"At the [Volta a] Catalunya [in March] I felt completely out of my depth. I am starting to feel progression and starting to feel better on the bike.
It's going to take time and I've got a lot of work to do. I’m prepared to do that work, that’s what drives me and gets me out of bed in the morning. I love the sacrifice and the whole regime and work side of being a professional cyclist.
"I'm not just going to throw in the towel. The more of those messages that come my way, the more it's going to spur me on and motivate me to do even more."
- - -
You can watch the Giro d'Italia live and ad-free on the Eurosport app and Eurosport.co.uk. Download the Eurosport app for iOS and Android now. You can also watch the most comprehensive live & ad-free racing on GCN+. Go deeper and get interactive with live polls & quizzes, plus rider profiles, race updates, results & more – plus stream exclusive cycling documentaries. Watch it all with GCN+ on any device.
'We're not superhuman' - Froome warns of abuse aimed at athletes
Cavendish and Froome headline strong field for Deutschland Tour