Wheelchair tennis is one of the forms of tennis adapted for those who have disabilities in their lower bodies. The size of courts, balls, and rackets are the same, but there are two major differences from pedestrian tennis, athletes use specially designed wheelchairs and the ball may bounce up to two times. The second bounce may also occur outside the court. This is one of the official Paralympic sports and also played at Grand Slams. There are three categories; Men, Ladies, and Quads and each category has singles and doubles tournaments.