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Swingweight

Q: I’m confused about swingweight. Let’s say I have two different racquets, one of which weighs 320 grams and has a swingweight of 300, and one that weighs 300 grams and has a swingweight of 320. Which is going to feel heavier, the lighter racquet with the higher swingweight, or the heavier racquet with the lower swingweight?

A: Swingweight is a measurement of racquet performance that is often ignored by players—assuming they even know about it in the first place—because it seems complicated, and it is difficult for the average person to measure. However, it can have a greater impact on how a racquet “feels” in play than the “pick-up weight,” which is what you feel when you grab a racquet by the handle and hold it horizontally.

A typical tennis stroke involves swinging a racquet around a point of rotation that is itself also moving. That is, you are both rotating the racquet, and “translating” it through the air. (You “translate” the racquet without rotation on a punch volley, for example: The entire racquet moves forward but the head does not rotate relative to the grip.)

When swinging your two racquets around a fixed point of rotation, the one with the higher swingweight will feel heavier. When translating your racquets, the racquet with the higher mass will feel heavier. For strokes that involve rotation and translation, you will feel a combination of swingweight and mass, although the amount of the contribution of the mass will depend to an extent on the angle at which you are holding the racquet relative to the court surface.

Keep in mind that racquet balance also changes as you change weight and swingweight. For racquets weighing the same, the higher the swingweight, the higher the balance point will be, as you can see in the accompanying table. In your case, the lighter racquet with the higher swingweight has close to even balance, while the heavier racquet with the lower swingweight is head light.

If you want to delve more into swingweight and effect of other racquet characteristics, check out our books, Technical Tennis and The Physics and Technology of Tennis.

From the January 2006 issue
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