What is the twistweight?
The twistweight, or polar moment, is basically the moment of inertia about a twist of the longitudinal axis. Basically, it obeys the same laws as the swingweight, only about a different axis. The farther the mass is from the axis of rotation, the greater the effect on the twistweight. Applied to a tennis racquet, a higher twistweight means increased stability against lateral twisting, but also a decrease in the maneuverability of a racquet. If you don't hit a ball exactly in the middle of the racquet, a higher twistweight means that the racquet doesn't twist as easily. Thus, when hitting off-center, less energy is wasted in twisting than with a low twistweight, and the racquet feels more stable. A typical twistweight for tournament racquet is between 12-15 kg*cm².