Why Should You Keep Your Knees Flexed While in the Golf Swing?

Knee movements in golf are more subtle than those of your hips and shoulders, but without proper knee positioning your hips and shoulders can’t rotate as they should. Just try to take a practice swing while keeping your knees straight and you’ll understand how important it is to flex your knees.

Balance

Former PGA Tour great Tom Watson notes that the key to remaining balanced during your golf swing is to center your weight on the balls of your feet. This will be difficult to accomplish in a normal golf swing if your knees are straight, without lifting your heels off the ground. Flexing your knees, however, makes it easy to shift your weight forward and balance on the balls of your feet in the address position.

Backswing

Each knee performs a different function on the backswing. The left knee of a right-handed golfer bends a bit deeper and points back to the golfer’s right, to allow the hips to rotate properly. The right knee, however, doesn’t increase its flex. Rather, it remains in position and acts as a brake on your hip rotation, preventing them from turning too far. Golf writer Steve Newell explains that by preventing your hips from rotating as far as your shoulders, you create a tight, spring-like effect on your upper body. That tightly coiled spring is then released on the downswing, helping to generate clubhead speed and leading to longer shots.

Preventing the Reverse Pivot

While some golf teachers advise players to reduce their right knee flex a bit on the backswing, it’s important to retain some flex in your rear knee. Watson explains that straightening your right leg completely commonly causes a reverse pivot in which your hips sway toward the target during the backswing. Most golf teachers advise players to move in the opposite direction, shifting weight from the front to the back foot on the backswing. Even stack-and-tilt practitioners -- who don’t recommend such a weight shift -- warn golfers not to sway their hips toward the target during the backswing, which limits your hip rotation and robs you of power.

Downswing

As you push off your back foot and your hips rotate during the downswing, both your knees will naturally move toward the target. But your knees should still remain flexed through impact. Newell explains that it’s particularly important to maintain good flex in your right knee when you’re hitting a driver. A flexed right knee keeps your right heel stay grounded longer, promoting the wider, shallower swing that you need when you’re sweeping the ball off the tee. Golf instructor Jim McLean recommends increasing your right knee flex during the downswing to help generate more power.

Conventional wisdom dictates that you also maintain a slightly flexed left knee through impact, to help you remain balanced and keep the clubhead on its proper path. But in his book, “How I Play Golf,” Tiger Woods says that occasionally, when he needs more distance, he’ll snap his left leg straight just before impact, which speeds up his swing. Woods notes that this move is “unorthodox.”