Every year between 250,000 and 300,000 athletes suffer a tear or more complicated injury involving the ACL (anterior cruciate ligament, found in the knee). You hear about it all of the time in sports. Just last year 11 NFL players saw their season end early due to this injury.
The statistics are staggering for those who tear the ACL, and it seems the complications that arise are not as easily solved after surgery. In fact, according to the American College of Sports Medicine, "of 400,000 ACL reconstructions, up to five percent risk re-injury, up to 45 percent fail to return to their pre-injury sport level, and up to 80 to 90 percent develop radiographic evidence of osteoarthritis (as early as seven years post surgery)." In more recent years, the amount of female-related ACL injuries have become an epidemic.
Women, who participate in sports like volleyball, soccer and basketball, are reported to be up to 10 times more at risk for injury to the ACL over men. While "high-risk noncontact deceleration activities, such as jump-cut maneuvers are not well understood," it has been found through research that women were more likely to perform these activities more "upright" with greater stiffness in their landing (or deceleration) than men. Since approximately 70 percent of ACL injuries occur during deceleration, and without contact from another athlete, we must understand what causes female athletes to be at such high risk.
According to research, "women tend to land with less hip and knee flexion (bending of the joint) and exhibit greater knee and lower hip extensor (straightening of the limb) moments." This weaker hip extensor deficit is believed to be due to a "compensatory strategy whereby women adopt an overreliance on their quadriceps (thigh) and passive restraints in the frontal plane (ligaments) to absorb impact forces."
Hip extensors (butt muscles) are of the upmost importance, when it comes to an athlete's ability to decelerate the center of one's mass during a landing — meaning an athlete will benefit with more of a bend in the knee, than absorbing force straight-legged. Since it has been suggested that women possess less strength in the hip extensors, as opposed to men, they, in turn, are more likely to overuse their knee extensors (thighs), thus, resulting in a tendency to exhibit "excessive quadriceps force increasing anterior shear loads at the knee joint and subsequent strain on the ACL."
East Jefferson General Hospital orthopedic surgeon William Sherman believes that women in explosive sports (such as soccer and volleyball) are more likely to sustain ACL tears for the following reason: female athletes typically have a more valgus (outward angulation of the joint) alignment than males when landing and pivoting, resulting in a larger moment of stress through the knee during landing and deceleration.
Of course, as with all sports, proper conditioning of the body and its mechanics can largely prevent such injuries. Sherman states that the way a female athlete jumps, lands and pivots can drastically reduce the number of ACL injuries when trained to counteract this outward tendency. Without proper conditioning, an athlete (more so female) places him or herself at larger risk of ACL deficient knees. This long-term instability can lead to early meniscal (cartilage shock absorbers in the knee) degeneration, which, in turn, predisposes an athlete to early arthritis.
It appears that once a female athlete tears her ACL, she can be at risk in the future for a similar tear in either the opposite or the same leg. I experienced this situation first-hand with a client who was a college female soccer player (who turned professional) and tore her ACL on the uninjured leg during a competitive match in which a collision was involved. She had previously torn her other ACL while performing a cutting move to the ball. In the latter case, a female opponent targeted her knee to take her out. Who says female athletics is not aggressive in nature?
It is important for any female athlete in explosive sports like soccer, who has never experienced an ACL injury, to head this warning, as it was found that female athletes who have never had ACL reconstruction were more likely to perform a jump-cut maneuver "with a greater landing stiffness than males with or without a history of ACL reconstruction and females with said history."
In my opinion, the key to preventing ACL injury is to be aware of the mechanics that cause the non-contact–type injury. Through research, it has been determined that it can take upwards of five years post surgery to fully provide insight into an athlete's long-term recovery process. A little more attention to correct form can make all the difference, as poor form can lead to a future of pain and discomfort, and if severe enough, can often times result in some form of mental and physical debilitation.
I recommend strongly that all high schools with female sports participation in sports like soccer, volleyball and basketball consider introducing an ACL injury prevention program. From a parent's perspective with an adolescent female athlete in a school's sports program, I would demand that such a program be put in place. You have now been forewarned. Rarely are there any second chances to correct a mistake after the injury occurs.