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Defining swingweight

Q: I thought I knew the definition of “swingweight” until I had someone ask me to tell him. Now I’m wondering, what exactly is swingweight?

A: Our Stringer’s Glossary defines swingweight as, “A measurement of the weight of the racquet in motion, which takes into account the static mass (weight) of the racquet, the distribution of that mass along the racquet, and the length of the racquet.”

The key phrase in this definition is “in motion,” because when you pick up a racquet by the handle and hold it parallel to the ground, you have some idea about the static mass of the racquet (heavy or light) and the distribution of mass along the length of the racquet (weight more toward the butt cap or more toward the tip of the hoop).

Once you swing that racquet in an arc around your hand, however, you are generating swingweight. Swingweight can be thought of as the outward pull exerted on your hand (the pivot point) as you rotate the racquet around that axis. It represents every molecule in the racquet and strings, at the distance each molecule is from the pivot point under your hand. The distance from the pivot point is important because 1) the farther away the mass is from the pivot point, the more mechanical advantage it has relative to your hand, and 2) the farther away the mass is from the pivot point, the faster it moves when the racquet is swung.

To illustrate, imagine two racquets with the same overall weight, one of which has all the weight in the handle and the other of which has all the weight in the head. The one with all the weight in the handle would have a low swingweight, while the one with all the weight in the head would have a high swingweight. The racquet with the lower swingweight would be easier to maneuver, because the mass is closer to the pivot point under your hand. The racquet with the higher swingweight would be more difficult to maneuver, because of the distance between the mass and the pivot point.

From the February 2006 issue
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