Jason Robinson said he "needed" controversial Channel 4 show The Jump because it has challenged him in a way nothing else has since he retired from professional rugby.
The former England captain, 42, is one of the seven celebrities competing in the final of Sunday's show to win the coveted cowbell trophy.
The skiing spectacular, hosted by Davina McCall, has grabbed headlines in previous years with a number of the celebrity contestants forced to pull out due to injury.
Robinson told the Press Association: "It's been something that to be honest with you I needed, because when you finish as a professional sportsman, you've scaled the heights. I played in three world cups, I've done everything I could ever want to do in both codes of rugby.
"Once you finish, it's like what now, what can I get my teeth into, what's going to give me some satisfaction, what other challenges lie ahead and, to be honest, I haven't had any challenges like that, something to really get my teeth into that I've never done before and this has given me almost a hunger to do more stuff."
Finalist and former Olympic gymnast Louis Smith has been the favourite to win in recent weeks.
Robinson said that while Smith was "the strongest in most disciplines", he also praised finalist and beauty queen Amy Willerton as being a "good skier" and said Made in Chelsea's Spencer Matthews had been "doing very well, he's a good jumper".
Britain's most decorated Olympian, Sir Bradley Wiggins, was forced to quit the show after suffering an injury, while rugby player Gareth Thomas announced this week he had to leave the competition due to "personal reasons".
Asked if Sir Bradley's injury had deterred him at all, Robinson said: "I spent my career being around that, in rugby injuries are a regular occurrence so it's not dented my confidence or anything at all.
"And for everybody else, this is an opportunity everybody has just grabbed and really enjoyed. We've known from day one there are risks to it, it's a sport, it's skiing and injuries can happen. That said, there have not been that many injuries and everybody has gone about the challenge in the same manner, they want to win.
"You've got Olympians, you've got people who have trained at the highest level in different sports, so the competitiveness from everybody has been ferocious."
However, he added that finalists like reality TV star Matthews who "loves extreme sports, he loves adrenalin and he would love nothing better than to beat an Olympian or World Cup winner, so everyone has come into this wanting to win".
Sunday night's other finalists include Paralympic medallist Kadeena Cox, socialite Emma Parker Bowles and The Only Way Is Essex star Lydia Bright, who stepped in to replace Thomas in the finale.
The finalists will have to battle it out in the snow cross and ski cross events in the hopes of making it to the ski jump to prove their jumping prowess.
Last year's series was won by rugby player Ben Cohen and in 2015 rugby player Mike Tindall was pipped to the post at the last minute by reality TV star Joey Essex.
Robinson said: "There' s a lot of pressure because Mike almost won it, Ben won it last year, so for the rugby fans I need to try and continue that."
:: The Jump final airs on Channel 4 at 8:30pm.