Anterior cruciate ligament (ACL) disruption is a common and potentially devastating injury. ACL injuries are most common in cutting and planting sports such as basketball, soccer and volleyball. Studies have shown that women tear the ACL in the knee 4 to 6 times more often than men. Researchers at the Coach Krzyzewski Human Performance Laboratory at Duke University wanted to find out why and how.

They used motion capture and electromyography showing the posture of 20 recreational athletics performing cutting, landing and stopping movements. These were men and women who worked out four times a week in sports that included jogging, soccer, basketball and aerobics.

In general, the women stood up straighter when performing these maneuvers. They used their quadriceps (muscles on the front of their thighs) more and had a tendency to angle their knees outward. The men relied more on their hamstrings and were in a more crouched position. This appears to have a protective affect. They also found that the quadriceps muscles alone can generate enough force to tear the ACL and sometimes the ACL can be ruptured through a simple cutting maneuver. It�s the torque or rotational motion that�s so problematic. That�s why a torn ACL is so common on the ski slopes and tennis courts.

What can women do to help prevent ACL injuries? Exercises which strengthen the hamstrings over the quadriceps may help reduce the number of ACL injuries which occur in contact sports. Techniques of cutting, stopping, and landing which alleviate the strain on the ACL might be developed which could also reduce the number of ACL injuries. Athletic teams are working hard to prevent injuries with conditioning and exercise techniques. Conditioning coaches are now simulating athletic movements during games, emphasizing correct posture and proper alignment. They are also having athletes perform strengthening exercises for their thighs, hips, hamstrings, abdomen and lower back and get them flexible enough to withstand twisting and turning, starting and stopping, on the court.