During the act of swinging a golf club, a slight flexing of the knees is necessary to ensure proper swing mechanics, and your legs must be strong enough to maintain that flex throughout your swing.

Often, average golfers have weak and/or tight quadriceps and hamstring muscles; and at some time during the four-and-a-half hours a typical round takes, golfers legs fatigue and become incapable of maintaining adequate knee flex.

In order to compensate for this weakness, golfers straighten their knees, thereby altering their spine angle and resulting in inconsistent, errant and short shots.

There are a number of potential causes for "coming out of your posture" or "losing your spine angle." However, the most likely culprit is improper knee flex.

If you need proof, just observe any pro's address position. You will almost always notice a slight knee flex regardless of which club they are swinging.

What steps can you take to avoid this problem? The best place to start is with a fitness program that incorporates leg exercises targeting the quadriceps and hamstrings. The stronger your legs are, the easier it will be for you to maintain adequate flexibility in your knees.

The "Squat" can be performed on or off the course

Golf Trainer Mike Pedersen practices the "lunge"

Give these two exercises a try and watch how easy it is to maintain your knee flex and stay in your posture. Just a little bit of work off the course will pay huge dividends on the course. Mike Pedersen is a leading fitness expert, and president and founder of Golf-Trainer.com and the Golf Trainer Power Performance Program™. A regular contributor to GOLF MAGAZINE and GOLFONLINE, Mike emphasizes a fitness-based approach to achieving a consistent golf game. E-mail Mike with questions or comments at golfonline@golf-trainer.com or call 866-266-7200.