I am a right hander. I have noticed that if I try to lengthen my back swing, my left arm bends at the top of my back swing. And when my left arm is completely straight, I feel as if I am only at half swing. But with that straight left arm and supposedly half back swing, the ball goes a nice distance and feels like distance is same as compared to when I try to lengthen my back swing.
That makes me think that keeping the left arm straight during the back swing is more important than the length of the back swing. Also length of the back swing is not that critical to achieve good distance.
Am I correct ?