What is Swing Path in Golf?

Swing path is the single most misunderstood number in golf. It is not where the club went on the way back, and it is not where the ball is aimed — it is the horizontal angle of clubhead travel at the moment the face strikes the ball, measured against your target line. A path that runs from inside the line out toward the right of the target (for a right-handed golfer) is called inside-out. The opposite — moving across the ball from outside the line back to the inside — is called outside-in, and it is the engine behind the slice.

The reason swing path matters is that, combined with the angle of the clubface at impact, it determines what the ball does in the air. A clubface that is open relative to the swing path will impart left-to-right side spin and curve the ball away from the target. A face that is closed relative to the path will hook the ball. The ball's start direction is mostly determined by the face, while the curve is mostly determined by the gap between the face and the path. Path on its own does not slice the ball — face-to-path mismatch does.

Most amateurs assume their slice is caused by an open face. Often it isn't. It's caused by an outside-in path combined with a face that is square to the target but very open relative to the path. Fix the path and the slice usually goes away on its own.