The Ski Sunday host, 44, shared a wince-inducing video of herself jumping off a five-metre platform into Lake Annecy in the French Alps during a family holiday.
The four-time Winter Olympian and Winter Olympics host was left struggling to breathe after the jump and was rushed to hospital.
“Most people badly time a front flip off a five metre platform and get winded. I apparently don't do things by halves, collapsed lung, chest drain and a very expensive lesson in rotation,” she said in the clip on Instagram on Thursday.
Alcott captioned the clip: 'Well… that escalated quickly. Turns out 5 metres is quite a long way to discover you’ve got the rotation wrong.
“One badly timed front flip. One very hard landing. One collapsed lung. One chest drain. And a few more hospital overnights than were on the holiday itinerary… I absolutely LOVED Annecy… but I’m not entirely sure it loved me back.”
Alcott added that after her jump, she rushed back to the top of the five-metre board to jump a second time because she was so “embarrassed”.
”Re my reel, I actually went back up straight away in embarrassment and did this just so I wasn't making a big deal of it,” she wrote on her Instagram Story.
“Then I realised I still couldn't breathe properly and should probably go get it checked out.”
The Brighton-born skier is on holiday with her two sons and fellow former British skier husband Dougie Crawford.
Alcott retired from skiing in 2014 and counts Zara and Mike Tindall as friends.
The Team GB downhill skier, who has broken her leg three times in four years, quit skiing after being told by doctors that another fracture would result in her leg being amputated.
She has turned to presenting and hosted BBC One’s coverage of the Winter Olympics in Milan and Cortina earlier this year.
“I have a very healthy relationship with fear. So many times, I’ve stared down a mountain, ready to throw myself down and knowing there’s a chance it could go badly,” she told The Sun in February.
“It’s kind of the same with TV. When we’re going live on TV and you hear the countdown, there are butterflies in the tummy.
“You get those same butterflies in the starting gate, ready to go racing at 80mph with loads of G-force down a mountain. It’s live. Anything can go wrong or you can have the ride of your life.“