Maintaining a stable posture throughout the golf swing is essential for power, consistency and lower scores. But the proper posture doesn't come simply from practicing swing mechanics. You need to train specific muscles, too.
Think of your spine as a radio tower with four guide wires that keep it stable and allow you to swing properly. The first wire is your rectus abdominis (the six pack). The second is the glute (butt) muscles. The other two are the right and left oblique abdominals (under the love handles). If any of these muscles are weak, it will create slack in a wire and the tower (posture) can break down at various points in the swing.
Keep those wires strong, and you'll improve your swing, lower your scores and prevent injury.