In order to create the type of power necessary to hit the ball far you have to engage the large muscles of your back and hips. In the golf swing they are the main source of power. In the middle of all these big muscles is your spine. it is the axis about which you rotate these large muscles. It's important that you understand what the proper positioning of the spine is throughout the swing. Basically, in a nutshell, the angle of the spine remains constant throughout the swing until you are well into the follow-through.
The easiest way to make sure you have the proper spine angle is to get it right at the beginning when you address the ball. To achieve a proper spine angle at address, bend forward from the hips while keeping your spine as straight as possible. A straight spine bends your torso forward so your arms hang freely from the shoulders. Bend until the hands are approximately six inches from the thighs. As you bend from the hips, don't lock your legs. Instead, maintain a slight flex in your knees. To make the most effective turn, your spine must be as straight as possible. Keep your chin up rather than dropping it toward your chest. If the chin drops, the top of the spine will curve.