With the 89th PGA Championship at Southern Hills Country Club right around the corner in August, talk is heating up about how difficult the set-up of this already challenging course will be. Similar to the U.S. Open at Oakmont C.C., earlier this year, a difficult set-up could lead to high scores, with even the Champion finishing over par.

Unlike the U.S. Golf Association, which aims to "preserve par" in the Opens, The PGA of America typically prefers to give players in its Championship the opportunity to "score" - that is, make birdies. Nevertheless, players should expect to have their hands full when they gather in the searing August heat of Tulsa for "The Season's Final Major...Glory's Last Shot."

One of the major differences in golf course set up between a major championship and other tournaments and amateur play is the width of the fairways and the depth and thickness of the rough. This week, let's take a look at why letting the grass grow just a few centimeters higher than normal can give even the best players in the world fits.

A ball that settles down in grass over one inch deep will have a strong effect on the outcome of the shot. There are two types of effects that the rough has on a golf shot. The first effect is a situation where there is grass between the club face and the ball at impact. With the diameter of the ball being 1.68 inches, when grass is covering the equator of the ball or more, the contact between club and ball will be significantly affected.

When a player finds the ball with rough covering the back equator of the ball it becomes necessary to adjust the swing so as to make as descending a blow as possible. This will put the least amount of grass between the club face and the ball. The choice of a more vertical path - with the shaft tilted so the handle is ahead of the ball position - will take effective loft off the shot. This shot requires a very quick hinging of the wrists and a limited follow through, as the club head drives downwards.

The second effect is when the grass impairs the flight path of the ball as it travels off the club. When the lie in the rough leaves grass covering the equator of the ball on the opposite, or target side of the ball, the launch and spin will be altered. As the ball travels upward, the thicker and longer the grass it must travel through, the more the speed of the shot will be altered, causing the it to travel a shorter distance and in many cases off line.

In both examples above, the spin rate of the ball is also lowered. This lowered spin rate causes the ball to fly lower and roll out a longer distance, making difficult for players to stop their ball on the lightning quick greens typical of major championship venues. In either case, the club of choice is one with more loft, to get the ball above the grass as soon as possible, and to stop rolling on the green as soon as possible.

The effects of long grass make ball flight a highly varied outcome. This is why rough adds to scores at major championships, and in your weekend game. When asked about playing from heavy rough, former PGA Champion Sam Snead once said, "Just don't go there." Great advice, but unfortunately very few of us can heed it!

For expert advice on playing out of the rough - or better yet, avoiding it - contact your local PGA Professional and enroll in a comprehensive instruction program, such as the PGA Golf Schools at the PGA Learning Center in Port St. Lucie, Fla. If you are out of our area, visit www.PlayGolfAmerica.com to find PGA Professionals with similar programs located near you.

Until next time, here's to better golf!

Rick Martino is Director of Instruction for The PGA of America. He teaches at the PGA Learning Center in Port St. Lucie, Fla., and is ranked among the Top 50 instructors by Golf Digest Magazine. The author of the PGA Manual of Golf (Warner Books/$34.95), Martino can be reached at (800) 800-GOLF or by email at pgalearningcenter@pgahq.com.