The film opens on the image of a young man with close-cropped red hair and a flaming goatee in a dark sweat suit sitting on the edge of a bed. He lifts himself up by his muscular arms and transfers to a strange wheelchair with battered metallic shields protecting the spokes and begins to struggle with his pants. He  slides them down long, pale legs, which he moves back and forth by hand, to reveal black athletic shorts and dark tribal-style tattoos on his calves.

Over chugging heavy metal music and interspersed between the film’s titles, our tattooed hero and others are seen on a basketball court ramming and jamming each other, slaloming through the spaces between each other, and occasionally flying out of their chairs after a nasty impact with their armored chariots landing on top of them.

This is not the quadriplegia you father told you about. This is Murderball!

In fact, “murderball” is the name first given to a sport now better known as “quad rugby,” a sport invented by a daring and dangerously bored group of Canadian quadriplegics in the 1970s in which two teams of four compete to get a volleyball across a line at either end of a basketball court. Players are strapped in chairs specially adapted to withstand repeated collisions. You don’t have to be quadriplegic to play the game, but you do have to have a certain combination of upper and lower body impairments. A point system in which each player’s disability is rated on a scale of .5 to 3.5, the lower indicating the greater disability, ensures that no team is more disabled than another: each team is required to have its members’ rating total no more than 8 during play.

From its humble beginnings in a Canadian rehab hospital, the sport has grown (with a little help from the more marketable name change) into an international phenomenon and is now part of the semi-annual Paralympic Games. But outside the world of adaptive sports, not many have heard of, let alone seen, quad rugby in action.

Murderball, a fast-paced documentary featuring larger-than-life characters engaged in a rivalry with Greek tragic overtones, should correct some of that. It should also do much to correct the way viewers see people with disabilities in general and people with quadriplegia in particular.  There has never been another film on the subject of disability quite like this funny, profane and humanizing documentary. That the subjects are in wheelchairs is almost beside the point. The viewer is too caught up in the drama to see anything but the whole, imperfect human beings enacting it.

The film follows the progress of two bitter adversaries in the world of international quad rugby competition in the two years leading up to the 2004 Athens Paralympics.  The red-haired gentleman we see at the beginning of the film is Mark Zupan, one of the stars of the dominant Team USA, the number one-seeded team in the world as the film starts.

At the 2002 World Championships in Gothenburg, Sweden, we meet one of Zupan’s former teammates, Joe Soares, who is now coach of Team Canada.  It becomes clear watching Soares’s intensity as he huddles with his team that the impending match against Team USA is personal for him. Soares is in the market for revenge on a team that he believes disposed of him, not for not being good enough, but for being, in his forties, over the hill. In a knuckle-biter of a game, Team Canada vindicates Soares, who isn’t too proud too gloat. “How does it feel to betray your country?” one of the defeated Americans asks him.

As the film follows the players pursuing the ultimate goal of Paralympic gold, we go deeper into their personal stories in several compelling subthreads.

We learn that Zupan, a former star athlete in a Florida high school, was injured when he and his best friend went drinking and driving. Zupan wound up being thrown from the passenger seat into a cold canal by the side of a highway, hanging onto a felled tree for several hours before he was rescued. Now he decides to entice his friend, Chris Igoe, to come see him play as a way of working through the guilt Igoe has been carrying with him for a decade.

Soares, the son of a Portuguese immigrant who became a cop in a Boston suburb, has difficulty expressing his feelings with his worshipful son, Robert, a sensitive 12-year-old who is better at schoolwork and music than at sports. During one painful moment, Soares toasts his Canadian team, whom he’s hosting in his Tampa Bay home, as “the sons I never had.” But a heart attack (the remedy of which we witness, courtesy of the filmmakers) produces a figurative change of heart in Soares, as well.

Coincidentally, while meeting newly injured quadriplegics at Kessler Rehabilitation Institute in New Jersey, the filmmakers found themselves focusing on a dirt bike fanatic from Long Island named Keith Cavill who was struggling to come to terms with his new life as a quadriplegic in the wake of an accident on his bike. Cavill provides several of the most amazing, painfully honest and eye-opening moments in the film, including one when Zupan visits the hospital looking for recruits and lets Cavill take the controls of a rugby chair.

Into this largely masculine world, we are also introduced to the women who love and are attracted to these men. In addition to the sometimes long-suffering but always devoted wives and girlfriends, we also meet sexually curious barflies and other denizens of life on the road. The film also answers some of the things we always wanted to know about sex after quadriplegia but were afraid to ask.

(Parents planning to take small children to this film—or any child younger than 17—should be forewarned that, in addition to streams of colorful trash-talk flowing from the players’ mouths, the film also contains episodes of frankness on the subject of sex, including some graphic demonstrations from “how to” films. The film has been rated R by the MPAA.)

Filmmakers Dana Adam Shapiro, Jeffrey Mandel and Henry Alex Rubin shot the film guerilla-style and by the seat of their pants. They used spare wheelchairs as improvised dollies, maintaining a wheelchair-user’s eye view of the goings on as much as possible throughout. “The only drawback to the ‘wheelchair shot,” says Rubin, the most experienced member of the team with several feature films and a couple of documentaries under his belt, “was the passers-by who kept stopping us to ask how we injured ourselves.”

Murderball is the first film and brainchild of former Columbia roommates Shapiro and Mandel and is distributed by Think Film.  It has been a crowd-pleaser at this year’s Sundance, where it won the Special Jury Prize for editing, and at the New Directors/New Fims Festival at Lincoln Center in March. The film goes into major theatrical release on July 8.

Chris Pierson is editor of Orbit.