Slouched posture is a common problem for golfers. When your shoulders get rounded and your back gets hunched, it forces you to get too close to the ball and you effectively get in your own way. Your arms can’t swing freely and you either have to rock your body out of the way during the stroke or flip the putter through impact. Instead, follow Brandon’s keys:
Proper Putting Posture:
Make sure you start with a putter that you’ve been properly fit
Stand tall and set your hands in a proper grip (see tip above).
Keep your back reasonably flat and move your elbows out and in front of your chest cavity.
Now keeep your knees “tall” (little knee flex) as you hinge from your hips and sole the putter on the putting surface. Your weight should slightly favor your toes.
Your chest should be up, your shoulders should be held back slightly and your arms should be hanging softly from your shoulders. You should feel like you’ve created plenty of space under your chest for your arms to swing.
Maintain this posture as you move your feet to align the putter and address the ball.
Finally, at address, your eyes should be directly over or slightly inside the inner edge of the golf ball you are addressing. To check this, get into your posture and hold a second golf ball up to your left eye (for a right-handed golfer). Drop it. It should strike the inside half of the ball you are addressing or make contact with the green just inside the object ball.