There seem to be two divided camps. One telling players to hit harder, be more aggressive, and attack relentlessly. Another telling players to construct the point and play with consistency and margin. Sometimes this debate becomes associated with the American versus the European style of play. Can’t we all just get along...?
As with most conflicting beliefs, the answer is somewhere in the middle. It’s not black or white. And it’s not as if you fall in either the camp of consistency or the camp of aggression. Consistency and aggression are at opposite ends of a spectrum in which players fall in somewhere in between.
Let’s look at both extremes. Playing with increased aggression will at some point have diminishing returns. Aiming at the lines will produce more winners, but it doesn’t make sense if only 40% of the balls go in. Therefore, aiming closer and closer to the lines or hitting harder and harder has diminishing returns. On the flip side, playing with increased margin will also at some point will have diminishing returns because if you chose to increase your margin of error to make 100% of your shots, you’d sacrifice placement and power to the extent your opponent would have a field day.
Long story short, there’s a delicate balance - a "yin and yang" if you will. Each day that balance changes. If your strokes are feeling good, you might lean toward the side of aggression. If your strokes are off but the body is feeling good, then you might increase your margins and slug it out physically. A delicate balance indeed...
In tennis, everybody wants to hit a “heavy” ball. What does that even mean...?
Say you were trying to apply force on an object, there’s a difference between a “slap” and a “punch” even if your hand is moving with the same velocity. A slap clearly has no weight behind it, while a punch drives through the target at impact. In a serious fight, my guess is you'd rather be throwing punches.
In physics, they say force = mass x acceleration. A lot of coaches emphasize racquet head peed, but it’s not the actually pure swing speed that you’re looking for. Sometimes a slower swing might produce a heavier, more powerful shot. Hitting “heavy" involves you engaging your legs and core strength through the ball, giving the ball weight/mass that slapping at the ball does not.
Tennis is like body building in the sense that you can only improve so quickly. In body building terms, you can only bulk up so fast. A body builder does thousands of reps for such incremental gains just how a tennis player must hit thousands of balls before any noticeable improvement.
Development is a long, arduous process, so you must 1) adjust your expectations accordingly and 2) take the approach of sculpting a piece of art. You can’t get a six pack overnight - everyone knows that. But if you keep chipping away at that sculpture, you’ll end up with something beautiful over time. However, if you don’t start now and put in the work to chip away at that sculpture, it doesn’t matter how much time passes. You’ll have that same ugly hunk of stone.