The Volleyball (sitting) event was introduced at the Arnhem 1980 Paralympics. Volleyball is governed by the World Organization for Volleyball for the Disabled (WOVD). In 2008, there are athletes from around 50 countries practicing the sport. A high level of teamwork, skill, strategy and intensity is needed in Volleyball. Each team's goal is to pass the ball over the net and to touch the ball on the ground of the opposing team's side. Male and female athletes with a physical disability are eligible to participate and must fulfil the conditions of a minimum degree of disability. Teams consist of mixed classes in male and female events, with six on court at one time. At all times the athlete's pelvis must touch the ground and the service block is allowed. Because Sitting Volleyball requires a smaller court (10m x 6m) and lower net, the game is considerably faster than the standing event. The game lasts up to five sets and the winning team is the first to win three sets. The team winning the set is the one to reaches 25 points, with at least a two-point lead.