Digging through your closet, you find a container of tennis balls. How long they’ve been there, you don’t know, but you decide it’s high time you had a practice session. An hour later, you’re on the court, baffled at how badly you’re playing. But take heart -- your fading skills might not be to blame. Instead, aging tennis balls might be the culprit.
Most common types of tennis balls are packaged in pressurized containers. The containers help maintain the air pressure within the tennis balls, ensuring they bounce properly after contacting the court’s surface or the strings of a racket. But if you break the seal and then store the tennis balls, over time the air will diffuse from the tennis balls. Even if you don't open a sealed container, it's still possible for air to leak out slowly, causing the tennis balls to lose effectiveness.
Loss of Pressure
When a tennis ball loses its pressurized state, it becomes less bouncy. The exact effect it will have on your game depends on your playing style. Generally, you'll have to hit the ball harder to make up for the reduced bounciness. Also, the tennis ball might not bounce as high after contacting the ground or a racket. There’s no standard time for deciding when to throw away tennis balls. Generally, if you notice a difference, it’s time to get new balls. Also, manufacturers might have specific recommendations, so check the container for instructions.
Loss of Nap
Depending on how often you play with the same set of tennis balls, they might start to lose their nap, which is the term for the fine, hairy fuzz across a ball’s surface. The more often you use a ball, the more its nap disappears due to wear and tear. Eventually, a well-used tennis ball will be much smoother than a fresh tennis ball, which can affect the way the tennis ball reacts after you hit it. That’s because the nap of a tennis ball traps a layer of air, which is why a tennis ball drops precipitously after you hit it with top spin. The technical term for the phenomenon is the Magnus effect, and without a proper nap, a tennis ball might not drop properly. The nap also affects how the ball reacts to the surface of the court.
The problem with playing with aging tennis balls is the lack of consistency. You don't want to develop, for example, a serving style that depends on using a flat tennis ball, only to find out during a game that your serve doesn't work as well with fresh tennis balls. In other words, practicing with fresh tennis balls helps ensure your playing style remains relevant to actual game situations. For this reason, it's always best to use a fresh set of tennis balls before practicing or playing a game.
Pressureless Tennis Balls
It's also possible to play with pressureless tennis balls, although you might notice a difference between them and traditional tennis balls. The advantage of pressureless tennis balls is they don’t have pressure to lose, meaning they stay consistent. But the disadvantage is that switching back to pressurized balls later might throw off your game. Also, pressureless balls can lose their nap, just like any other ball. If you’re not sure what kind of balls to use, test different brands or ask a tennis instructor for advice.
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