One of the first pieces of swing wisdom a beginning golfer hears is that you have to keep your left arm straight. What that means, and how it's expressed in a good golf swing, requires accurate interpretation.

Let's talk first about what a straight arm is. If you stand up and let your arm hang at your side, you'll see there's a slight bend at the elbow. In terms of how humans are built, this is straight. If you stretch your arm out so it is truly straight, it's full of tension and isn't of any use in hitting a golf ball. Thus when we talk of a straight arm we mean one that has its natural bend in it.

[Note: Instead of talking about the left arm from now on, which leaves left-handed golfers in a constant state of transposition, we'll talk about the arm closest to the target when you address the ball and call it the leading arm.]

The golf swing is built around the swinging motion of the leading arm. When you address the ball, this arm and the club form the radius of a circle, the length of which must not change. Now it's true that the club part of the radius does change as the wrists hinge on the backswing, but that's all right. The club will return to its original position when the wrists release on the downswing if the leading arm has not shortened in the meantime.

Ensure your leading arm stays straight on the backswing by pulling it up to the top with your right hand. As you pull, feel as if you're stretching (but not straightening) the leading arm away from the target as it goes up. This feeling will also help you make a complete shoulder turn, a critical part of a good backswing.

Here's a check you can do. When your leading arm is parallel to the ground on the backswing, that shoulder should have rotated all the way to underneath your chin. If your shoulder hasn't moved that far, you've under-rotated your arm and have shortened the radius of your swing. Likewise, if your arm is bent more at any point in the backswing than it was at address, the radius has been shortened.

On the downswing, feel that the outside edge of your leading arm is falling toward the ball while having that same stretched feeling. That, along with the lower body turning into the shot, will deliver the clubhead right back to where it was at address. After impact, the leading arm will remain straight for a moment before it folds at the elbow as you come up to the finish position.

Having a sloppy leading arm can be a cause of inconsistent ball striking. Tighten that arm up in the way I have described and see if that doesn't make a big difference in how the ball flies away.

Bob Jones is dedicated to showing recreational golfers the little things, that anyone can install in their swing and game, that make a big difference in how they play. See more at website.