Get into your setup to the side of a full-length mirror. Is your lower back arched and your tailbone sticking out? If so, you’re standing in S-posture and placing undue stress on your lower back while letting your core relax — not good. The problem is often caused by “Lower Crossed Syndrome,” or combining a group of weak muscles with a group of tight muscles. The culprit can be something as innocuous as sitting in an office chair for eight hours a day, especially if you’re not engaged in a regular stretching program.
The best stretch you can do for your lower back (and your golf swing)
Correct your S-posture with exercises that teach you how to get into a neutral pelvic posture and brace your core muscles to stabilize that position. Cat-cows, for example, are a great first step. Get down on all fours and arch your back up as far as you can. Then push your chest as close to the ground as possible. Repeat in a slow and controlled manner 10 times. Recheck your posture in the mirror after a few weeks. You’ll look like the picture below. Now your posture is rock-solid.