Why can some people endure intense pain, while others cannot?
Australian cricketer Ryan Harris has dealt with chronic knee injuries for most of his cricketing career.
In fact, the 35-year-old fast bowler even calls pain his friend.
"[The pain] it's there every morning when I wake up, it's there when I go to bed at night."
"I've always had it since I was, you know probably 12 or 13 when I started bowling at a decent pace and it's something I guess I've had to live with for such a long time."
"That's why I call it my friend," he explains. "I'd love to meet a bowler who'd walk out onto a cricket field pain free – I don't think I've met one yet."
There's an oft cited saying "no pain no gain", meaning for any worthwhile endeavour, enduring intense suffering is often part and parcel of winning.
Indeed Jeffrey Mogil from Canada's McGill University explains, the ability to cope with pain may be a contributing factor in helping push people to succeed.
"Pain is more than one thing. It's a sensation, like vision or touch; it's an emotion, like anger or sadness; and it's also a 'drive state' that compels action, like hunger," Mogil is quoted as saying in The Globe and Mail newspaper.
Dr David Martin, Senior Physiologist for the Australian Institute of Sport, says elite athletes have a pretty high pain threshold, and that there is a pain barrier which resets each time you break it.
"With elite athletes, winners are grinners, it's amazing what (pain) they can cope with, (but) when that dream is over the pain is almost unbearable," Martin said.
Harris told Insight when he’s in the middle of play, he can distract himself from any pain he may feel.
"In my situation you're out in the middle of the ground, you're doing something that you love, you dream of doing, you've got your team mates there, you've got the crowd there, adrenalin kicks in, you just don't think about it," Harris said.
"You just let your mental capacity override any of that."
Boxing champion Shelley Watts also agrees. The Commonwealth gold medallist remembers one time when she couldn't even lift her arms leading into her final fight.
"I was thinking to myself, how am I supposed to lift them, put them into my guard and be able to throw the punches at this person?"
"But once you start to warm up, and once you realise, you know, you've got a task to do, it just completely goes. And I guess you just let your mental capacity override any of that," the 27-year-old Watts says.
Other sporting champions have also talked about their capacity to push past the pain.
Geraint Thomas continued riding in the Tour de France with a fractured pelvis, while Novak Djokovic played on with bleeding toes defeating Rafael Nadal in a gruelling five-set match which lasted almost six hours.
In a post-match interview Djokovic said: "You're in pain, you're suffering, you know that you're trying to activate your legs, you're trying to push yourself another point, just one more point, one more game."
"You're going through so much suffering your toes are bleeding. Everything is just outrageous, you know, but you're still enjoying that pain," the Serbian tennis star said of the 2012 Australian Open men's single final.
Runner-up Nadal adds: "When you are fit, when you have passion for the game, when you are ready to compete, you are able to suffer and enjoy suffering … I suffered during the match, but I enjoyed all the troubles that I had during all the match."
Do you think athletes have better pain tolerance? And is there a better way to control pain?
This week, an all new Insight explores how we deal with pain. Guests who feel no pain, phantom limb pain, chronic pain and sportspeople share their secrets for getting on top of niggling injuries.
This program investigates different types of pain, the relationship between the body and the mind, and the unusual ways in which pain can be treated. Tune in 8.30pm on SBS ONE.