Ireland, like most countries, wouldn’t be overendowed with candidates for a World XV.

Seán O'Brien is assuredly one of them. And without him the importance of another contender, namely Cian Healy, is even more acute. Indeed, it's not stretching things to suggest Healy's health is as important as any of the other vital cogs in this Irish team.

Joe Schmidt yesterday spoke of the ball-carrying workload being shared “across the backrow and even the secondrow”, but he assuredly knows Healy is as important in this regard. The player himself talks dutifully about his primary role as a scrummager, only after which can his ballast as a carrier come into play. Yet while he has consistently punched above his weight – 17st 8lbs (112kg) and 6ft 1in – in the set pieces, it is his ability to swat opponents and pump his legs in contact, or break tackles and accelerate, which truly sets him apart as a prop.

A hyperactive bundle of energy, if ever a player was born to run with the ball, it is Healy.

“That’s why I started rugby, because I was allowed pick up the ball and run, as opposed to kicking it along the ground . . . That’s pretty much why I went up to Clontarf and started,” says Healy, reducing his initial foray into, and love of, the game to its most simple.

Curiously, there’s no rugby in his bloodline. He started with the Clontarf under-eights at the insistence of a mate because he was big for his age, and rugby has been an ideal outlet for his innate energy and aggression. He owes Scott McGreal a debt, and though McGreal didn’t stay with the game for long himself they remain mates, recently hooking up again after McGreal returned from a couple of years working and travelling to Vietnam and Thailand.

Vintage crop
After a four-year introduction to the game with the Clontarf under

age set-up, Belvedere College applied a semi-professional outlook to the sport and Healy was part of a vintage team that won the Leinster Schools Senior Cup in 2005.

“I think Clontarf toughened me up a bit and Belvedere kind of polished it off.”

In Belvedere, athletics coach Phil Conway introduced him to a programme of weightlifting from second year onwards. Of the many coaches he had there, Andy Kenny improved Healy technically and taught him more of the game’s psychology.

During school and while working his way through the Leinster Academy, his old coaches from his underage days – Colm Carmichael and Aidan Murray – asked him to play centre from under-16s to under-20s. “Deadly,” he says. “Loved it. Drop goals and everything. Really, I embraced it. I was given carte blanche to do what I wanted. It was enjoyable.”

Healy is self-deprecating and says he only placed more focus on scrummaging late on. “That was about two years ago.”

Switching between hooker and prop in his school-playing days, Healy admits he relied on brute force and, initially, with Leinster could be unravelled by technically smarter props.

In the 2009-10 Heineken Cup semi-finals, Healy was given such a torrid time by Benoit Lecouls and the Toulouse scrum that Michael Cheika replaced him after 30 minutes. "I was raging. I was so fired up, because usually you're given your chance to try and dig it out and get it back. That was probably one of the experiences that fired me up most in rugby."

He credits Cheika for giving him his chance at a young age, and then Greg Feek for working on his technique although as much comes down to sheer desire and will. “If you’re thrown into a scrum against the best in the world and you want to survive, you will. You’re not going to throw in the towel and take a hiding.”

Sharper focus
Joe Schmidt has brought more direction to his natural looseness. "It's like being back at school; you're afraid to make a mistake. I know that if I screw up in training he'll throw Jack [

McGrath] in as quick. It keeps you on your toes, which is a good way to be.”

Healy admits he “loves” the new scrum regulations which reduces the impact of the hit. “I hated big heavy fellas standing two feet away from me and diving on the back of my neck. There’s a bit more technique to these scrums now and lot more depends on how strong you are as well, so it works in my favour.”

For a 26-year-old, he already has a huge body of work under his belt; 124 games for Leinster (including three Heineken Cups) along with 42 international caps. Yet there’s been low days too, the lowest being his first Lions start against the Western Force when his ankle and his world caved in, and he was subsequently cited for biting Force scrumhalf Brett Sheehan.

“Pain” is his abiding memory of that night in Perth, he admits with a chuckle. “I remember Jamie came over when I was still lying on the ground. I remember a good bit of it.”

He knew his tour was over immediately and to compound the misery he learned of the biting allegation hours later. “That was downright annoying. It taught me I better wear a gumshield. I immediately got filled with rage and wanted to go after that scrumhalf. That was very annoying.”

He travelled on to Brisbane, watched the Reds game, had a few farewell drinks that night and headed home with Gethin Jenkins the next day, “parked it” and set about enjoying his holidays in Egypt and Barcelona. It was his first major injury and the road back was complicated by the discovery of residual damage to his left ankle.

No less than his great mate Jamie Heaslip, Healy cannot let rugby dominate his life more than it already does.

“I can’t be completely submerged in rugby. I’ll hate it if I’m in it that much. Coming back from surgery, I had such a thirst to play. It was like being let out of the traps and running around headless looking for the ball. But if I don’t feel I can get away from it, it bogs me down. I need my space away from rugby.”

Music is his primary escape, although he’s abandoned being DJ Church because it meant too many late nights.

Musical distractions
"When I'm mixing I like house, but when I'm listening it's R&B. I like everything. I got the old 2Pac album again there, so that's big on me at the moment. I'm into the lyrics. It just completely empties your head. It's a nice clearance."

He has also painted abstract portraits of fellow players, and then there’s his pug, Ted.

Music is also a distraction on the mornings of games and en route by coach to matches.

“I used to be bloodthirsty hours before but I’ve had to tone it down. I have my caffeine and music peak from early in the morning, so on the bus it’s a few tunes to quieten down and relax and then once I get to the stadium the music is off and start to play the game a little bit in my head.”

An injury to his other ankle has interrupted this campaign and he returned to Leinster's colours as a replacement away to Castres like a man possessed. Just in the nick of time for his country and the Six Nations too, and having played all but one of the 20 games in the four tournaments since the 2009 Slam, Healy has become impatient.

“I want to win it. I’ve had too many Six Nations without winning it. Nothing else will do.”