According to sources, Rafael Nadal has decided to add weight to his racquet, the Babolat AeroPro Drive GT. In its stock iteration, the AeroPro Drive is 11.3 ounces (strung) and balanced 4 points head-light. Reportedly, Nadal is modifying his equipment with hopes of adding more speed to his serve.
"I had to make the change even if I am not better in the beginning," Nadal told reporters. "We had to make the decision so that it will be better in the future. Probably that hurts my game a little bit to begin with. Is that a risk at the beginning of the season—yes. But it was still the right moment, to change. If not now, then when?"
It is not yet clear how much extra heft has been added to the frame. (Remember: How mass is distributed through a racquet, whether toward the tip or butt, directly affects its balance point.) Still, the question naturally arises: What are the consequences of a heavier racquet for Nadal's game?
First, let's briefly speak to how a racquet's mass affects its playability. All other things being equal, heavier racquets are more powerful. As physicists Rod Cross and Crawford Lindsey, in Technical Tennis, write, "If a heavy and a light racquet are each swung at the same speed, the ball will come off the heavy racquet faster because the heavy racquet has more momentum and more energy that it can transfer to the ball, and it will lose less energy."
The caveat, of course, is that a player may not be able to swing a heavy racquet as fast as a light racquet. Heavy racquets are relatively more difficult to accelerate, not to mention maneuver; and so, for a recreational player in average physical condition, a heavy racquet may not in fact increase speed of shot. (Though they may, as Cross and Lindsey note, provide a bit more control, as "they don't need to be swung as fast to achieve the same ball speed.")
Tour players, on the other hand, are exceptionally fit and technically accomplished; Nadal, as we all know, is one of the fittest and accomplished of them all. So, with a heavier racquet, will Nadal be able to maintain his racquet-head acceleration through the ball? Will a heavier racquet give Nadal more power—and, by extension, more free points on his serve?
I would answer a tentative yes, though to what extent is far from clear. (I'll try to find out more about Nadal's racquet tinkering, and will report back if and when I do.) In the meanwhile, we'll just have to watch and see.
—In a press conference at the Qatar Exxonmobile Open this past Monday, Nadal clarified, as a commenter below noted, that the weight was added to the top of the racquet—a strategy for increasing service speed: "...I trying to play with a little bit heavier racquet and on the top of the racquet to get a little bit more power...I try to play with a little bit heavier than what this racquet is today, but we take the position that we have to change the racquet or we try to have to change the racquet. Not the racquet, only the weight, no?"
—Many of the comments below have expressed concern that the increase in racquet mass will negatively affect Nadal's sore shoulder. But it may in fact be that players using heavier racquets are less likely to suffer arm injuries. Consider the following passage from Cross and Lindsey in Technical Tennis:
"In theory, a heavier racquet should help to reduce arm injuries. There is anecdotal evidence from veteran coaches that arm and shoulder injuries increased when heavy, wood racquets were replaced with modern, light racquets at the end of the 1970s. When you strike a ball coming towards you, the ball tends to push the racquet head backward as your arm swings forward. Alternatively, the head slows down while your hand is still accelerating. Light racquets get pushed backward more than heavy racquets. A sudden twist of the arm or the wrist, repeated many times, can result in tennis elbow and other injuries. The problem is magnified by the fact that light racquets need to be swung faster to pack the same punch as heavy racquets, so the impact shock is likely to be greater, especially if you miss-hit the ball near the tip of the racquet or near one edge."