When I was coaching, I would frequently hear parents and students talk about the need to hit hard. Children as young as eight often told me they needed to smack the ball as hard as possible to become good at tennis. And parents would express concern when their child hasn't been hitting hard and fast during practice. Many of you reading this blog might be thinking along the same lines--that the better players are the ones who hit harder. So, my job is to change your belief on the importance of hitting hard.
Of all the elements in tennis, hitting the ball hard is the last one you should focus on. If you start telling yourself to hit hard in the early years of your tennis game, it could get in the way of your development. You might forget to work on your technique and almost always lose sight of strategy. Think of a car with a Ferrari engine. You know a Ferrari will make good use of a 600 horsepower engine because everything else about the car is built to handle the incredible power of that engine. Now, take that Ferrari engine and install it into a small car with tiny tires. You could certainly go full throttle with that engine, but the car will likely spin off the road and the tires may pop. That's what happens when your main premise on the court is to hit hard. So, unless you're already developed technically and physically, avoid that. You'll have trouble to keep the ball in play and you may eventually injure yourself from tensing up too much too frequently.
It takes years of quality training before a player can start thinking about hitting their shots hard without making too many mistakes. You'll know when you reach that stage of your game. In the meantime, focus on consistency, good form, and placement. Certain things about form, for example, such as using your body weight and keeping your arms relaxed, will increase power naturally. But, that happens without even thinking about hitting hard. To win matches, however, you need to play the numbers game: it's consistency, cutting down the errors, and placement, preventing your opponent from controlling the point, that will get you more wins.
Here are two tasks for your next few practice sessions:
(1) When you rally, try making at least 30 balls in. While you're doing this, figure out what's the hardest you can hit during that 30-ball rally.
(2) Play a match without trying to hit a single ball hard. It doesn't mean you should hit soft, just solid enough to control your shots and placement. You may find yourself playing better.