Sometimes my forehand breaks down and sails several feet long (am using an Eastern FH grip with relatively flat strokes). I suspect two likely possibilities: 1. Racquet face is too open at contact causing the ball to go long. 2. Racquet face is in correct position at contact, but swing path is too linear -- need more of a low to high swing path. But I am not able to easily figure out during a match which is the problem.. Forehand usually come back after I miss a few, but I want to be able to recognize the root cause immediately during a match.