JACK NICKLAUS: In my prime, my legs were very strong. My right thigh was 29.5 inches and my left was 28.5. I always wanted a stable base for my swing, and my hips did not move sideways. They turned, as if in a barrel.
I didn't so much think of shifting my weight to my right side on the backswing, but rather I pressured it. Keeping my right knee flexed, I pressured my weight into my right leg and my right hip. And I turned my shoulders about 110 degrees, so I was able to get into a big, powerful position at the top.
The feeling was that my feet started that move going back, and because of the momentum of the club, my entire body ended up in that strong position. This created a lot of leverage for the club to swing down forcefully into the ball. It helped me generate serious clubhead speed.
JIM FLICK: The average golfer would do well to emulate Jack's rotary -- not sliding -- motion. Jack let his left heel come off the ground to keep his hips level through the swing, which is why he felt his weight "pressure" into his right side.
The classic teacher from the 1930s Percy Boomer coined the phrase "Turn in a barrel." Boomer recognized that turning around your body, rather than sliding your hips sideways, results in more consistency. It's difficult to hit it solid when you move off the ball on the backswing, because you have to move back to the ball the exact same amount to hit it flush. That takes more talent than most golfers have and more practice than they can afford.
The head might move a bit away from the target on the backswing so you don't create a reverse weight shift. But if you lack consistency, try staying more centered over the ball.
Jack Nicklaus writes articles only for Golf Digest.
Jim Flick, a longtime Golf Digest Teaching Professional and PGA Golf Professional Hall of Famer, worked with hundreds of amateurs and tour players including Jack Nicklaus.