Your knees should be slightly flexed and directly over the balls of your feet for balance. The center of the upper spine (between your shoulder blades), knees and balls of the feet should be stacked when viewed from behind the ball on the target line. Also, the back knee should be cocked slightly inward towards the target. This will help you brace yourself on this leg during the back swing, thus preventing lower body sway.

Your body should bend at the hips, not in the waist (your buttocks will protrude slightly when you are in this correct posture). The spine is the axis of rotation for the swing, so it should be bent towards the ball from the hips at approximately a 45-degree angle to the shaft of the club. This right angle relationship between the spine and the shaft will help you swing the club, arms and body as a team on the correct plane.

Your vertebrae should be in a straight line with no bending in the middle of the spine. If your spine is in a "slouch" posture, every degree of bend decreases your shoulder turn by 1.5 degrees. Your ability to turn the shoulders on the back swing equals your power potential, so keep your spine in line for longer drives and more consistent ball striking.

Video: Correct golf posture