Participating in exercise and sports should be encouraged for everyone regardless of age or sex and should be a positive experience. Unfortunately, sports-related injuries can occur. For individuals participating in sports that involve cutting or pivoting, a particularly challenging injury is one to the anterior cruciate ligament (ACL). When the ACL is injured, it is considered a season ending injury that most often requires surgical reconstruction in order for the athlete to return to competitive play.  When an athlete tears her/his ACL, it can be pretty devastating because the surgery typically requires 6 to 9 months to complete rehabilitation.  The purpose of this article is examine why ACL injuries occur at higher rates in female athletes and what specific neuromuscular training can lessen the chances of ACL injuries.

Since the passage of Title IX in 1972, girl’s participation in high school sports have increased dramatically by up to 900% .(1)  Over the past decade, female athletic performance have dramatically increased in speed, power and intensity.   This aggressive style of play has led to an increase of muscular injuries, namely the sprain of rupture of the anterior cruciate ligament (ACL), as the more common one.

Studies show that adolescent female athletes have a four to six times higher rate of ACL injuries compared to their male counterparts (Dharamsi, A., & LaBella, C. (2013). Research has shown that injuries start at the onset of puberty and could be the result of hormonal, anatomical, biomechanical, and muscular changes that the female body experiences during this time.

What is the ACL and an ACL injury:

   ACL is one of 4 major ligaments that stabilize the knee by keeping the tibia from sliding forward in relation to the femur. It also restricts excessive knee extension, tibial rotation, and varus and valgus knee displacement.   In addition, the ACL protects the menisci from damage that could occur while jumping, cutting or quick change in direction with deceleration, and lateral movements in sports (Marx, R. (2012).

ACL injuries occurs more commonly after a moderate to high velocity trauma along with rotational force on the knee. (for example, when the feet are planted one way and the knees are turned another way) or when landing from a jump.    Since landing from a jump is the most common mechanism for ACL injury in both genders, variations in movement patterns, in male and female athletes, during the early landing phase following a jump have  been established (Beutler,(2009))  The typical ACL injury is a non-contact injury that occurs while the athlete is pushing off twisting, pivoting or changing direction while decelerating.

Causes of ACL injuries in Female Athletes.

 There are many studies that show why female athletes are more susceptible to ACL injuries then their male counterparts.  These include hormonal, biomechanical and neuromuscular.

 Hormonal:  The highest prevalence of sports injuries in children and adolescents occurs at the onset of and during puberty, corresponding with the adolescent growth spurt. During puberty, girls do not display an accelerated increase in muscle strength.  In addition, hamstring muscle strength appears to lag behind that of  quadriceps strength.  Therefore, this substantial increase in quad strength vs. hamstring muscles, may impede their ability to stabilize their knee and protect the ACL during dynamic landing movements, contributing to a greater risk of ACL injuries (Wild).

 Biomechanical and neuromuscular:  Muscular strength and recruitment patterns are crucial to knee stability.  Researchers found that even though men and women both landed stiffly from a jump — where the quads are tensed, which is already a risk factor for ACL tear — women had a 3.6-fold increased risk of landing “knock-kneed” compared with men.  During puberty, female quad development is faster then hamstring development.  With greater quad activity during landing, and decreased hamstring activity, investigators have identified that female athletes are more quadriceps dominant compared to male athletes.  Thus, this would encourage a more extended knee posture during landing, resulting in greater ACL injuries.  Female athletes also have less core stability and strength making it more difficult for them to control their center of mass and prevent it from shifting away from the base of support (Myer).

Prevention.

Implementing various neuromuscular training (NMT) programs designed to strengthen hamstring and core muscles, improve balance, and teach athletes how to recognize and avoid dynamic knee valgus is important to reduce the risk of ACL injuries.

Athletes should be shown how to recognize and avoid unsafe knee position by correcting improper form and not allowing athletes to progress to more challenging exercises until they have demonstrated consistently proper form with less difficult exercises.

Conclusions

Studies have shown that female athletes have a 2 – 3 times higher ACl injuries then male athletes.  The current research has shown that increased knock -kneed during the landing phase of a jumping motion indicate a greater chance of ACL injuries in female athletes as compared to male athletes.   Additionally, female athletes have been shown to experience ACL injuries at the onset of puberty; thus, concluding that hormonal changes and neuromuscular growth in females may also attribute to ACL injuries.

Developing and implementing proper neuromuscular training to strengthen muscles surrounding the knee, flexibity, myofascial release and training in dynamic motions will benefit the female athlete and help lessen the chances of ACL injuries.

References:

  1. http://www.womenssportsfoundation.org/home/athletes
  2. (Dharamsi, A., & LaBella, C. (2013). Prevention of ACL injuries in adolescent female athletes. Contemporary Pediatrics, 30(7), 12-20.)
  3. (Marx, R. (2012). The ACL Solution: Prevention and Recovery for Sports Most Devastating Knee Injury. New York: Demos Medical Publishing).
  4. Beutler, A. I., de la Motte, S. J., Marshall, S. W., Padua, D. A., & Boden, B. P. (2009). Muscle strength and qualitative jump-landing differences in male and female military cadets: The jump-ACL study. Journal Of Sports Science & Medicine, 8(4), 663-671.
  5. Silvers, H.J. (2009). Play at Your Own Risk, the injury Epidemic, and ACL Injury Prevention in Female Athletes. Journal of Intercollegiate Sport, 2(1), 81-98.
  6. Wild, C. Y., Steele, J. R., & Munro, B. I. (2012). Why Do Girls Sustain More Anterior Cruciate Ligament Injuries Than Boys?: A Review of the Changes in Estrogen and Musculoskeletal Structure and Function during Puberty. Sports Medicine, 42(9), 733-749.
  7. Myer GD, Stroube BW, DiCesare CA, et al.(2013). Augmented feedback sup- ports skill transfer and reduces high-risk injury landing mechanics: a double-blind, randomized controlled laboratory study. Am J Sports Med.;41(3):669-677.