If there is a lesson in Tiger Woods' injuries for the millions of Americans who golf, it is that they shouldn't presume they will suffer the same fate -- at least not while on the course.
People generally do not tear their anterior cruciate ligament or suffer a double stress fracture while playing golf, sports medicine experts said Wednesday, but the intense twisting action forced upon the front knee during a swing can worsen an underlying problem.
"Because it's a controlled swing, by and large, golfers don't run into knee problems unless they have an underlying condition," said Dr. Ronald Grelsamer, associate professor of orthopedic surgery at Mt. Sinai Hospital who specializes in knee surgery. "In which case, the twisting involved in golf can exacerbate the symptoms of that condition. But you are not going to get arthritis, tear a ligament, or get stress fractures from playing golf."
That view is supported by a study published in 1998 in the Journal of American Sports Medicine, which said that despite the high amount of force applied to the knee during the swing, the force is not great enough to pose a high risk of traumatic knee injury.
Still, the front knee takes quite a beating during a swing.
According to preliminary results of a study conducted by Dr. Clifford Colwell of the Scripps Clinic in La Jolla, the force on the front knee during a swing can be 4.5 times a person's body weight. Comparatively, jogging exerts a force of 4.3 times a person's body weight.
During the downswing and into the follow-through, when the front foot remains planted and the hips begin to turn, the knee bears the brunt of the force, said Dr. Greg Rose, co-founder of the Titleist Performance Institute.
"When the hip rotates it's like twisting a necktie and twisting the top," Rose said. "The knee is the guy in the middle taking all the torque."
If there is underlying tenderness, the swing can lead to other injuries not suffered by Woods.
A torn meniscus is the most common injury to the front knee, often taking six weeks to heal. The recovery time can fluctuate, however, depending on the size and location of the tears and other abnormalities found in the knee, said Dr. Richard Ferkel, assistant clinical professor of orthopedic surgery at UCLA. Another injury seen in golfers is damaged articular cartilage, which can take nine months to a year to recover from, Ferkel added.
Experts say it is crucial for golfers to remain loose during a swing to avoid a knee injury.
Longtime local golf coach Eddie Merrins said if a player's leg is straight as he swings, the joints within the knee lock and can cause damage. Instead, Merrins recommended "bowing" the knee to the outside to limit damage to the joints.
"A lot of it depends on the way you're swinging," Ferkel added. "Is your motion correct or incorrect? If you have a normal, easy swing that allows for free motion, that will diminish the potential of getting a knee injury, but if you twist it abnormally or change the mechanics of your swing abnormally, that can cause problems."