Flyball is a relay race that matches two teams of four dogs each, racing side-by-side over a Flyball course. The course consists of a starting line, 4 hurdles spaced 10 feet apart and a box. The first hurdle is 6 feet from the start line and the box is 15 feet from the last hurdle for a 51 foot overall length. The dogs jump the hurdles and step on a spring loaded box that shoots out a tennis ball. The dog catches the tennis ball and then runs back over the 4 hurdles. When the returning dog crosses the starting line the next dog goes. The first team to have all 4 dogs run without errors wins the heat. Tournaments are usually organized in either a double elimination or round robin format. Double elimination is usually the best of 3 or best of 5. Round robin is usually best 3 out of 5 and the first team to win 3 heats receives 1 point towards their standing in the tournament.