Wheelchair rugby (originally murderball, and known as quad rugby in the United States) is a team sport for athletes with a disability. It is practised in over twenty-five countries around the world and is a summer Paralympic sport. Wheelchair rugby is played indoors on a hardwood court, and physical contact between wheelchairs is an integral part of the game. The rules include elements from wheelchair basketball, ice hockey, handball and rugby union. The sport is governed by the International Wheelchair Rugby Federation (IWRF) which was established in 1993.