The Jump contestant James "Arg" Argent has said week one challenge the skeleton bob gave him "sleepless nights".
Channel 4 released a first look video of the celebrity sports series which starts tonight.
In the footage, The Only Way Is Essex (Towie) star is seen riding haphazardly around the frozen track in Austria as he lies face down on the small sled.
According to the broadcaster, Argent came off his skeleton completely on one of his initial attempts.
After that, the 28-year-old was unsure about tackling the track again, but he overcame his fears.
Argent later admitted to some trepidation about what lies ahead.
"First week of training," he said. "I'm not going to lie, there have been so many ups and downs. I was excited and up for the challenge, but the skeleton knocked me for six.
"After sleepless nights, flashbacks, bruises and cuts I'm now happy to put the skeleton behind me."
Conversely, Girls Aloud singer Sarah Harding loved the skeleton and wanted to go even faster.
For some of the stars in training, it has been a bumpy ride.
Former EastEnders actress Louisa Lytton was taken to hospital on Wednesday after a fall during a practice session on the slopes.
The 26-year-old suffered some bruising. On a previous occasion, she tore a ligament in her thumb.
The Jump, which is filmed in the Austrian Alps, will see 12 celebrities tackle various winter sport-related activities.
The winner is awarded the Cowbell Trophy, currently held by Towie star Joey Essex who won last year's series.
The other nine 2016 celebrity participants are: Made In Chelsea's Mark-Francis Vandelli, Holby City actress Tina Hobley and former EastEnders star Sid Owen.
The show has also attracted Olympians in the form of golden girl swimmer Rebecca Adlington and gold medal-winning athlete Linford Christie.
Gymnast Beth Tweddle, who won a bronze medal at London 2012, rounds off the sports personalities.
Finally, socialite Tamara Beckwith and ex-Westlife singer Brian McFadden are joined by US actor Dean Cain, best known for playing Superman on the small screen.
Popular presenter Davina McCall returns to the Austrian Alps to host the show, which has moved to a new weekly format instead of being shown daily as the previous series had been.
The celebrities at the bottom of the leaderboard will face The Air Jump on tonight's live show.
The aim is to get as much height as possible by jumping off the 4 ½ metre kicker and landing safely into a giant airbag.
It will take skill and athleticism to gain the air and height needed to stay in the competition.
The Jump starts tonight at 7.30pm on Channel 4.