An improper swing plane. The swing plane is the path that the golf club travels on. A slice can happen whether you have an upright or flat swing. What most golfers do is move the club first on the take away by rolling their left wrist to the right without any shoulder and arm movement. In doing this they have opened the clubface. This means that if you are hitting a 5 iron, by rolling your left wrist you have given that 5 iron the loft of an 8 iron. The ball will go higher and much shorter while going to the right. The cure, of course, is to make sure that the knuckles of your left hand do not turn to face the sky on your take away. This can only be accomplished if your left shoulder pushes your arms and the club away.
Another cause of a slice is the move many of you make from the top of your back swing. Most golfers main concern is to get the ball airborne and in doing so drop their right shoulders much too drastically to get the club under the ball. This causes the club to open up & add loft. I ask you, how can a ball go straight if the club is going under the ball instead of hitting the back of the ball while moving at the target?
The third cause could be a stiffening of the right leg on the backswing causing a reverse weight shift. When this happens the golfer falls backward as he is swinging forward.
GOOD LUCK
