On the football field, the uniform is a suit of armor that makes players feel invincible and has the NFL in a sudden scramble to make the game safe. On the rugby pitch, where the action is every bit as vicious, they've been playing for decades with little more than a paper–thin set of shoulder pads.
These are two violent games, each of which produce more than their fair share of injuries.
But if a rugby player is going to get "blown up" — as they like to say in the NFL — the sound will be that of bone–on–bone, not the loud, made–for–TV popping of a helmet onto a pair of shoulder pads.
"When you put those pads and helmets on, it does protect you, but only to an extent," said Eddie O'Sullivan, a former rugby player in Ireland who now serves as head coach for the U.S. national team.
By eschewing pads and helmets, rugby players say they avoid the perils of the so–called "Superman effect," a sensation that emboldens players to take bigger chances and make bigger hits because they feel safeguarded by equipment that essentially turns them into armor–plated projectiles.
"A helmet would actually be seen as a form of protection, so that would massively change the way the game is played," said Chris Jones, who has played for the Sale Sharks rugby union team in Britain for 10 years. "It wouldn't really suit rugby to wear helmets."
Indeed, helmets and thick shoulder pads would alter the fundamentals of rugby — especially the tackling part, which has less to do with knocking an opponent to the ground, more to do with wrapping him up and keeping him there.
"It's a more precise skill, rather than just the car wreck effect that you see on the gridiron, and that's the thing that keeps the game pretty safe for us," O'Sullivan said.
Rugby players are taught to never use their head in making the tackle, and without a helmet to protect them, the logic is pretty clear. Any player leading with the head is almost certain to get hurt as badly as the person he's trying to hit.
Meanwhile, ballcarriers in rugby — a game with continuous play and no forward passes — are also taught that it's better to go down easily so they can more effectively work the ball back to a teammate and keep play moving.
This is not the way of the NFL, and suddenly, the league finds itself in the midst of a safety crisis.
On Sunday, a new era in the NFL will begin, one in which extra scrutiny will be given to hits made at shoulder level and above. Players who have been taught since childhood to hit hard, and often to lead with their helmet and shoulders, have become confused about what's allowable and what's not.
In the middle of this debate, a couple of the sport's icons, Penn State coach Joe Paterno and former Bears coach and tight end Mike Ditka, have suggested helmets either be scaled back or completely eliminated from football — an almost certainly unworkable prospect that would make football look the way it did in the 1940s and 1950s ... and more similar to what rugby still looks like today.
"I don't think people would strike with the head as much," Ditka said during the week. "You would learn to strike with the shoulder pads if you didn't have a helmet on your head."
While they're far from helmets, rugby does make "scrum caps" — soft, padded head guards — available, though they are mainly used to protect players from getting their ears bents and tweaked during scrums. The caps, more recently, have fallen out of favor because players think they feel awkward and don't want to appear "soft" by wearing them. Instead, many favor tying a simple cloth or elastic band around their heads to protect their ears.
Jones is among the few who still wears a scrum cap.
"It might take a slight edge off a big hit but I think it's just psychological," he said. "It makes you think you can go into areas that you otherwise might think you shouldn't."
Most rugby players also wear mouth guards and shoulder pads, though the pads can't be thicker than 1 centimeter and are almost imperceptible beneath their striped rugby shirts.
The lack of padding and emphasis on tackling technique isn't to say they don't glorify violence in rugby the way they do in the NFL. It's just that the debate about right and wrong is much more cut and dried.
In one clip on rugbydump.com — a website devoted to showing some of the hardest hits on the rugby pitch — Fritz Lee of the Counties Manukau team in New Zealand is shown clotheslining a runner on a breakaway in a desperation attempt to bring him down. The website calls it "one of the worst looking hits you'll see for some time," and even though the player he hits bounces up immediately, the announcers instantly start talking about how long Lee's suspension will last.
He got three weeks and will return for his team's game Sunday.
Brutal as the play was, however, it almost certainly would not have stood out as the worst from last week's NFL games had it been lumped into the replays of hits that caused the league to toughen its policy.
"You see the hits on the gridiron and you can tell, if you took the pads off the footballers, they would have to stop and teach people how to tackle or they would kill each other," O'Sullivan said.
O'Sullivan isn't claiming, though, that rugby has all the answers to injury prevention.
A study done by the B.C. Injury Research in Canada says rugby injuries come at almost three times the rate as those in football and soccer. But another study performed by the Eastern Suburbs Sports Medicine Centre in Sydney and the Australian Rugby Union found that while head injuries were most common in the collection of games they studied — adding up to 25 percent of all injuries — three–quarters of those injuries were lacerations, while only 19 percent were concussions.
Meanwhile, both sports struggle to keep accurate concussion statistics.
Last season, the NFL mandated that any player who gets a concussion should not return to action on the same day if he shows certain signs or symptoms. The International Rugby Board has a rule that calls for players to take a three–week break after being diagnosed with a concussion.
"The unintended effect of all those rules is that people are extremely reluctant to admit they have a concussion," said Mark Lovell, the founding director of the University of Pittsburgh Medical Center Sports Medicine Concussion Program. "There's potential incentive for people to not recognize it because you could lose a player. In rugby, and in football, it's a thing they're always grappling with."