Typically, golfers are taught to keep their left arm straight. It’s like a mantra—Don’t bend your left elbow.
The advice is sound in principle, but not necessar­ily a must for a good golf swing.

This is not to say the left arm can be allowed to totally flex (1). This will lead to a wide variety of problems.

To create the proper angle in your left arm, allow your right arm to dic­tate. Your right arm should never be allowed to bend farther than 90 degrees at your elbow. At this angle of the right arm, the left arm will not flex beyond an acceptable amount.

Noted golf instruct or David Leadbetter has come up with a device to help you perfect this tech­nique (below right). This device pre­vents your right arm from flexing more than 90 degrees, thus putting your left arm at the proper angle (2). Practice with this device on the driving range. This will help you to condition your right arm to flex the correct amount. This will allow you to forget about your left arm and swing without worries.

Using the Leadbetter device in front of a mirror is important to help you see exactly how the arm should look. You can visualize this image on the golf course, and com­bined with the muscle memory of your right bicep, you will find it eas­ier to keep your arms in the correct position.
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