I spent much of the early part of 1980 working on a full-swing change that my teacher, Jack Grout, and I had decided was overdue.
Always favoring an upright plane, I had allowed my shoulder turn and arm swing to become excessively steep, to the point of losing power and accuracy. The mind pictures that eventually got my shoulders turning more and tilting less, and my arms swinging less upward and farther behind me, derived from the word "deep." Try thinking "deep" on the backswing if you're having difficulty applying the club solidly to the back of the ball.
In 1979 I was swinging into the ball at such an oblique angle--and making a glancing blow--that I hit either pull-hooks or cut shots. Impact didn't sound very solid, and I was losing confidence.
What I learned then--and have reminded myself many times since--is that if you swing into the ball on a slightly shallower angle from inside the target line, you can hit it more solidly and with more speed and produce a draw or fade. It's like Newton's Law of Motion about an action resulting in an equal and opposite reaction. If your club comes into impact too much from the outside and too steeply, you can't transfer 100 percent of your power to the ball. Many amateurs suffer from this very problem.
Making a shallower swing into the ball definitely helped me regain my power and accuracy. It's no coincidence that I won the U.S. Open and PGA Championship in 1980 after I deepened my swing.
JACK NICKLAUS writes only for Golf Digest. In this series he updates his classic lessons published by the magazine.