Tennis balls are pressurized to maintain their bounce. When a tennis ball is manufactured, air is forced inside the ball under pressure. This pressurized air inside the ball gives it the desired bounce. When the ball hits the ground, the pressure inside the ball causes it to rebound, making it bounce.
The International Tennis Federation (ITF) has specific regulations for how high a tennis ball must bounce. According to the ITF, a new ball must bounce between 53 inches and 58 inches when dropped from a height of 100 inches onto a concrete floor.
This bounce height is achieved through the pressurization of the ball.
However, over time, the pressurized air inside the ball will slowly leak out, causing the ball to lose its bounce. This is why tennis balls are sold in pressurized cans. The cans are pressurized to the same pressure as inside the ball, preventing the air inside the ball from escaping until the can is opened.
Once the can is opened, the balls will start to lose their pressure. This is why professional tennis players use new balls frequently. In professional matches, new balls are used every 7 to 9 games to ensure they maintain the proper bounce.
As for actionable advice, if you’re a casual player, you don’t necessarily need to replace your balls as frequently as the professionals. However, if you notice that your balls are not bouncing as high as they used to, it might be time to replace them.