Law on Fixed Equipment on Tennis Courts
Regarding the number of tennis arbitrators: On a normal game field, there will be a referee, a referee and a person who picks the ball when standing in the right position is also considered a fixed device. However, having the highest level matches, there can be up to 11 referees on the field at the same time.
Game Rules of Tennis Ball Competition
The ball must have the same outer surface, covered with a felt layer and yellow or white. If there is a way to connect, it must not reveal stitches. The ball has a diameter of 6.35 cm to 6.67 cm, the weight ranges from 56 g to 59.4 g and the bouncing is in the range of 134, 62 cm to 147, 62 cm when dropping from a height of 254 cm down.
Type 1 – Fast speed: with forward distortion greater than 0.495 cm and less than 0.597 cm; the later deformation is 0.749 cm larger and 0.965 cm smaller when the 8,165 kg impact force is applied to the ball
Types 2 and 3 – Medium and slow speed: forward distortion greater than 0.559 cm and less than 0.737 cm; the later deformation is greater than 0,800 cm and less than 1,080 cm when the impact force is 8,165 kg.
When playing at altitudes above 1,219 m above sea level, two additional types of balls can be used:
– The first type has the same rules as described above, except the rebound value is in the range of 121.92 cm to 134.62 cm and has an internal pressure greater than the external pressure. This type is often called compression ball. The second type also has the criteria as described above, except for the value of bouncing in the range of 134.62 cm – 147.32 cm and having an internal pressure equivalent to the external pressure.