'Superhumans at 17 Sports' is the BBC's tag line for the Commonwealth Games. I think I have just discovered an 18th. And, when it comes to the freestyle knocking-back-bacon-sandwiches event, the England seven-a-side rugby team looks to have a foot on the medal podium. At the announcement of the squad's personnel a small mountain of sandwiches disappears within seconds of the players spotting them. It would be unfair to pick out individuals in a team effort but Paul Sampson of Wasps looks particularly handy coming in on the blind side of the brown sauce.

This, it seems, is typical; at the friendly games the rugby players are enjoying themselves. "It's been great so far," says Phil Greening, the team captain, leading the line for refreshment. "It's just a very different experience being part of a multi-sport event, mixing with athletes from other disciplines. We're looking forward to seeing it as well. The lads were saying they want to catch the sprinting and the weightlifting."

And the captain?

"Me? I've got different interests," he grins. "The gymnastics and the netball."

This is just what sevens used to be, a jolly at the end of the season, a bit of fun, a chance for the backs to stretch their legs away from the stop-start 15-man game. But, despite the captain's light-hearted demeanour, times have changed. In the professional era it has become a hugely competitive international travelling event, playing to big crowds, featuring specialist players.

"It's like the doubles in tennis, it's a totally different game from the 15-man," says Greening. "You look along the line and instead of 14 team-mates there's just you, one on one against an opponent. If he times his sidestep right, he's away and gone and you look a right idiot. I'm convinced that's why some top players don't want to touch sevens; they are scared of that sort of exposure."

Yet, when England warmed up for the Games by winning the sevens in Hong Kong in March, Gavin Hastings, the former Scotland captain, said it was the most significant victory for English rugby for 15 years. As a litmus test for the condition of the wider game, he reckoned, you can tell a lot from how a nation plays its sevens.

"That's right," says Greening. "Your technique in tackles and how you defend against someone has to be very good. If they break the line they score, bottom line. Again, when you've got the ball, if your pass isn't great you're very exposed. You can't afford to be sloppy."

And then there is the fitness.

"Blimey," says Greening, almost panting at the thought. "In most matches it's seven minutes each way, which is bad enough. But my first final was 20 minutes against the Kiwis; it was absolutely battering. You go back to 15s, you can't believe how slow it is. For skills and fitness there's nothing to touch sevens. That's why Warren Gatland [his coach at Wasps, a club who provide three of the England squad] encourages us to go away and play it. He knows when we come back we'll be flying."

"Flying" is not a word that used to be associated with Greening's role on a rugby field. He is, after all, a hooker. Stubby, tubby and slow, their job description did not involve any running business. But Greening represents a new breed.

"Yeah, that's it, the game changed. Clive [Woodward, the England manager] told me, 'Get your hands on the ball, cause damage, hit holes.' I model my game on Woody [the Irish hooker Keith Wood]. He's fantastic. He's moulded the future of the hooker, though I think I carry the hair off a bit better than Woody."

And he slaps his own distinctly hair-free head and grins. But even so, a hooker in sevens, no one expected that. In the past, if you mentioned sevens to them, they would assume you were talking about their ability to down pints.

"My role in this is to go round winning ball and giving it to the speed guys really," Greening says. "I'm the grafter who does the destructive work and the speed guys get the headlines."

There must be more to it.

"Yeah, well, I'll take all the line-outs. And I'll be organising the scrum. It's a three-man scrum, effectively just a front row. But you've got guys who normally play centre and full-back in there. So I've got to try and learn them a few little ways."

Ah, the dark arts of the front row, the place where men are men and gouge one another's eyes out to prove it. So, what really goes on in there?

"That would be telling," he says grinning again. "Phil Vickery's been telling me not to give too many people our secrets; we don't want them coming in and nicking our jobs. But the lads'll have to learn, won't they, when they've got some big Samoan shoving them back 10 yards. I tell you, they'll learn."

Greening himself has been a quick learner. Although he comes from rugby heartland in Gloucester, as a boy he played football and did not pick up an oval ball until 10 years ago, when friends persuaded him to give the game a go.

"I was about 15, liked it and got hooked. I started as a centre but I had too many pints and pies, I got a bit of weight on me and got pushed into the front row."

It was clearly his masochistic calling. He loved the new job: hanging there, arms over the shoulders of two team-mates, ears rubbing raw, hacking away at the ball as it entered the scrum, a claustrophobe's nightmare. The oddity of the hooker's trade is that, though it seems the least sensible place to put your head in world sport, its most celebrated aficionados - such as Wood and England's Brian Moore - away from the mayhem seem intelligent people.

"I don't know about Woody," chortles Greening. "And I know Brian's a solicitor but he's got a nail salon now. Not very front row that, is it? But they're both good lads. And I think it's this: you've got to have something about you to play there. You've got to have a combination of a bit of wile, bit of intelligence, plus a screw loose. Woody's a great character, totally mad, Brian's a bit bonkers, so am I. Yeah, I admit it, you've got to have something wrong with you to play where we do."

The problem for Greening has been that recently the something that was wrong with him was more physical than mental. After breaking into the England side he lost his place after a catalogue of injuries. Now Steve Thompson is in possession of the white No2 shirt and Greening has been sidelined. Hence the kind of hunger to perform in Manchester that cannot be satisfied by bacon rolls alone.

"I need this just to kick-start my career," he says of the games. "I've had virtually two years now of hell. I've been in the gutter, I've been depressed, I've come back from one injury, played a couple of games, got another, been out for months - makes you think there's someone up there doesn't like you. Not being involved in the England squad has been really depressing for me. I can't watch other lads out there doing it instead of me. I get really frustrated."

The frustration turned into depression, a spiral which he found hard to break.

"I was so depressed, awful, forgot I could play. Fair play to Warren Gatland at Wasps, he pulled me out, said: 'Yeah, go enjoy yourself, play sevens, get some confidence back.' I need to do that. Touch wood [he touches his head] I've had all my bad luck. I need this now to kick-start my rugby."

And, according to the captain, it is not only his own qualities that are in the shop window. The game as a whole can introduce itself to a wide new audience.

"I think there's a great opportunity here for English sport and I really think we need to do well. Rugby, netball, hockey, all of us need to lift the profile of our sports," he says. "But rugby, we need it massively. If we do well in the Commonwealth, I think a lot of people will sit up and take notice. Sevens is such a great game, and the best in the world are here. Football has about six pages in the papers and we get a little column in there. This is a big chance for us to get some of those pages. The boys are putting a lot of work in not to let that chance slip."

There may, if things go well, even be a touch of attention and glamour rubbing off on the hooker. Might children start lining up to learn the dark arts of the front row?

"Course they won't," he says. "They've seen the ears." And in truth, his ears are a sight. Never mind cauliflower, his are like two bits of sausage meat appended as if in afterthought to the sides of his head.

"We were training yesterday and all these Manchester scallies were watching, and they were going: 'Mister, look at your ears. I'm not playing rugby if that's what happens to you.' I told them you can get an operation when you finish."

Why not before?

"Well, it's a conversation starter. The women always want a little feel of them," he says, rubbing his damaged ears lovingly. "It's like sevens, you've got to use every angle."

Talking of which, has the captain received his allocation of the 30 Commonwealth condoms for each athlete? "I've heard the rugby players are getting 50," he laughs. As with the bacon sandwiches, it seems they always want more.