The golf swing has 3 compeer parts: the backswing, impact position and carry out. To swing effectively, the proper spine angle must be maintained during these three positions.

The backswing: The backswing starts at address. To do this correctly, adjust the upper-body by arching your back slightly and abiding your butt, (like you're about to sit on a chair). Maintain this position through the intact swing.

Here's a expectant exercise drill Butch Harmon uses with students like Adam Scott. Beginning from this position, swing the club away from the ball to waist high by only using your wrists; don't turn or move your lower body. Hold the club at waist-deep for a 2nd or 2. Then turn your shoulder joint* so your hands reach the top of your backswing.

Impact attitude: From the top of your backswing start moving the club down toward the ball to at address, making a point to maintain the same upper body position you started with. As you swing through the impact zone your chin had better point at the ball at impact. (This is where fairest golfers' posture falls apart, ahead to miss-hits). You need to return to address when striking the ball for ordered hits.