SWEET SPOT - WHERE, AND WHICH ONE? {1999}

By Vince Chiarelli, PTR, MRT and Owner of String Along With Vince in Largo

How big is your sweet spot? Actually, a more appropriate question would be, "WHERE is your sweet spot?" Your racquet actually has three sweet spots, not one. The one most advertisements refer to is technically known as the CENTER OF PERCUSSION, or COP. This is the point on the strings where shock is at a minimum, where you get the most comfortable (sweet) feel with ball impact. The other points which can be referred to as sweet spots are the NODE (the point where vibration is at a minimum) and (this is a great one) the MAXIMUM COEFICIENT OF RESTITUTION or COR. This is the spot where the most power is generated, given the same swing and ball speed. In the interest of brevity -- and sanity -- I'm going to concentrate on the point of least shock, but the general information regarding effectiveness applies to all. The accompanying diagram [appeared in original publication] will give you approximate locations of all three spots.

All three spots have certain factors in common. All are points, not large areas. The string bed of a racquet exhibits dynamic properties when contacting a ball that make the effect radiate out from each spot, gradually decreasing until it has no effect. What this means is that the farther you are from the spot, the less benefit you will get from it. Racquet companies usually show the effective area of the Center Of Percussion as a large shaded area on the racquet diagram.

To further complicate matters, the shape and size of the racquet, among other things, will influence the size of the effective area of the sweet spot as well as the location. A racquet with a triangular shaped head (large at the top and small at the bottom) will have higher sweet spots than the traditional ellipse shape. An oversize head will have an increased effective sweet spot area proportional to a mid-plus or mid-size frame. A super-oversize string bed attempts to enlarge the effective sweet spot area even more.

Part of the benefit of the Center Of Percussion is the stability of the racquet in your hand when the ball hits off center. Many companies have designed racquets to increase the sweet spot effective area to make the racquets more "forgiving" of off-center shots. However, like so much racquet technology, only you can judge if it works.

There are formulas to calculate the location of each of the three sweet spots, but they tend to be very complex and require measuring equipment not usually found in the average workshop. Those who are interested in a more detailed explanation can get in touch with the writer by phone or e-mail.

(Previously published in THE LATEST RACQUET - May/June, 1999)