The spec that saves your off centre balls has no marketing team

Twistweight governs how far the frame rotates on a mishit, and it explains more bad days than string tension ever will.

You hit a ball two inches out toward the tip and toward the outer edge. The frame twists in your hand, the string bed presents itself at an angle you did not choose, and the ball leaves in a direction that has nothing to do with your intention. Everybody blames the strings. Almost nobody blames the correct thing, which is resistance to rotation about the long axis of the racquet.

That resistance has a name, twistweight, and it comes from mass placed out at three and nine o'clock on the hoop. Not at twelve. Mass at twelve raises swingweight, which is a different problem entirely and one people confuse with this constantly. Mass at the sides does very little to swingweight and a great deal to stability on the sort of contact you make when you are late, stretched, or handling a ball that dipped further than you read.

Here is the argument I would actually pick a fight over. Twistweight matters more to the average player than to the professional, and the market has it exactly backwards. A tour player finds the middle of the string bed on the overwhelming majority of contacts, so the frame's behaviour on a bad hit is largely academic to them. A club player mishits constantly. That player is the one who needs a wide, stable, side weighted frame, and instead gets sold light head light frames because light equals easy in a shop.

There is a wrist and elbow story too, and it is not the one usually told. The sudden torque of a frame twisting is transmitted straight through the grip into the forearm. It is a short, sharp, off axis load, repeated a few hundred times a session for a player who mishits a lot. I would rather blame that than blame polyester for every case of lateral elbow pain, which has become the reflexive explanation.

The fix is cheap and slightly ugly. Two strips of lead tape at three and nine, four or five grams a side. Total cost of a few pounds. Your racquet will look like it has been in a workshop, because it has, and it will hold its line on the shots where you currently spray balls into the side fence.

Nobody sells a poster of lead tape. It still works better than most upgrades you can buy.