The eye-opening documentary Murderball takes an intriguing idea of introducing people to the sport of quad rugby, only to find even more drama and action taking place off the court.

That's largely because filmmakers Henry Alex Rubin and Dana Adam Shapiro had the good fortune to find a group of men that are as passionate about their sport as they are about life. Nicknamed Murderball, quad rugby is quickly, but effectively explained by the documentary as a fast-paced contest featuring teams of quadriplegics working to score goals, while attempting to avoid violent collisions from opponents. All competitors participate while riding in wheelchairs reinforced by metal, making them more like battering rams with wheels.

The players are quick to dispel a somewhat popular misconception of quadriplegics as people with no use of their limbs. They all have sustained neck and/or spinal cord fractures, but with varying degrees of limb disabilities, with those serving as ratings for the purpose of the sport. For example, someone who has little impairment in their limbs would rate a 3.0, while a 0.5 would be given to a player with little or next to no use of their limbs. Those ratings are then applied during the game, with no team allowed to have the players exceed 8.0 on the court at one time.

By the first time the sport is shown on camera, viewers are given a quick introduction into its excitement, with frequent shots of wheelchairs crashing into each other, occasionally knocking competitors over. But far from being intimidated by the sport's physical nature, these players thrive on it. They want to leave no doubt that they are not handicapped - they are athletes who just happen to compete in a wheelchair.

Away from the competition, the film largely focuses on the U.S. quad rugby team, as they compete in a pair of world championships (yes, this sport has participants from many countries) and the 2004 Paralympics in Athens, Greece. It also looks at the life of one of the team's former players, Joe Soares, who, bitter at being cut from the U.S. squad, decides to coach the Canadian national team. Soares, a fiercely competitive man, is seen by the U.S. team as a traitor, but is clearly a driving force in making the Canadian team a serious threat to the Americans longtime dominance in the sport. The fact that U.S. team leader Mark Zupan and Soares clearly dislike each other is played up to good dramatic and comic effect by the film.