The common concept of making power in the golf swing is of trying to keep the lower body from turning as the shoulders wind up the torso. This line of thinking uses the idea of unwinding the body to gain power as if the body were a big spring. Kind of like the unwinding rubber band that spins the propeller of a child’s model plane.
The body does not unwind like a spring, it uses its muscles to move its levers. To prove it to yourself grab your left hand with your right hand and twist your left arm as far (rotating it) without swinging it. Once you have twisted it as far as it will go, let go. It didn’t spin back, did it?
When we try to hold our lower body still we do not allow the levers of the lower body (the legs, feet and knees) to become properly positioned for the down swing. Nor have they been prepared for the upcoming event with the proper stretching of the muscles we need to reverse the motion. Many instructors teach the holding of the weight to the inside of the fight foot and the keeping of the right knee in a braced position.
There is no need for the feeling of being braced. We are not trying to hold the right leg still and create torque in it. We are instead readying it for the actions it must perform to first shift the weight to the left leg (which should act like a post) and then once the weight has shifted to rotate the pelvis on top of the posted left leg.
Rather than feeling as if we are holding the right knee from moving and the weight on the inside of the heel, the feeling is just sliding the hips to the right as the right knee straightens and the left knee and ankle flex.
The weight should initially feel to go to the outside edge of the right heel, and then after the weight has shifted as the shoulders turn the left hip will rotate in toward the ball and the weight will feel to return to the center of the right heel. At the top of the back swing the weight will be 95% on a straight right leg with the remaining 5% of the weight on the inside of the ball of the left foot and the big toe.
Going back we simply slam down the left heel and pull the left knee back under the left hip with no attempt to turn the left hip to the left. As you do this pick up your right heel and rotate it out toward the flight line. You should feel as if your belly goes up under the left arm as you try to pull your right shoulder blade into your right hip pocket using the lower back muscles on the right side of the back.
If you can maintain the feeling of the left arm remaining pinned to the chest as you also keep the chest wound to the right of the hips the shift of the weight will bring the left arm down the perfect plane. Simply twirl the club with the right hand and you will have a perfect swing.