By Mark Nemish
Performance Director

11.01.05

Sports offer great opportunities for young athletes to be competitive, have fun, and develop camaraderie and friendships with their teammates.  Along with competitive sport however, is the incidence of injury.  Injuries occur all over the body however one of the most frequent cites of injury is to athletes’ knees.  In a study published a number of years ago with regards to female basketball players, 91% of season ending injuries and 94% of injuries requiring surgery occurred in the knee.  The anterior cruciate ligament (ACL) is one of the most important stabilizing ligaments for the knee joint.  According to the research, season ending knee injuries have occurred at a rate of 1 in 10 female athletes annually at the intercollegiate level.  For female basketball players in high school alone, approximately 1 in 65 will rupture their ACL’s.  At a conservative cost for surgery of just under $20,000 and the traumatic effect of loss of playing time and loss of possible scholarship funding due to a severe ACL injury, one can imagine the financial and emotional costs. 

With increased participation in sport by females over the last few decades, a dramatic rise in the number of ACL injuries has occurred.  A 1993 study reported a six-fold higher incidence of ACL injury in females’ verses males.  Furthermore, two thirds of ACL injuries are non-contact in nature.  Why then are females so much more predisposed to tearing their ACL’s than males and why are these injuries predominantly occurring in non-contact situations?  To answer this question, one must look at the female anatomy and their lack of physical training in preparation for sport. 

Anatomically, females generally display a greater Q-angle.  This is characterized by wider hips than boys and their knees appearing as if they are turning inwardly towards each other.  At Dynamic Sports Performance (DSP), we see this relationship quite frequently in our young adult female athletes.  Inward rotation of the knee puts a much greater strain on the supportive structures of the knee joint.  Another explanation for the increased risk of ACL tears has to do with neuromuscular deficits which include ligament, quadriceps, and leg dominance. 

Ligament dominance refers to the lower body musculature not being able to adequately absorb the forces occurring in different sporting maneuvers, such 
 

as landing from jumps or making sharp cuts to change direction, thus resulting in excessive loading to the knee ligaments.  Studies have shown that when females land from jumps they have a greater tendency for their knees to move towards each other (vulgus stress) and for their lower legs to be forced forward (anterior tibial translation).  The ACL resists both knee vulgus and anterior tibial translation. 

Quadriceps dominance refers to the quadriceps (upper front thigh) muscles being much stronger and recruited more than the hamstring (back of thigh) muscles in sport situations.  This also causes greater anterior tibial translation and stress on the ACL.  Studies have shown that females tend to rely more on their quadriceps than their hamstrings when landing from jumps. 

Leg dominance occurs when there is an imbalance in the strength and power between the legs.  As a result, an athlete may rely too much on one leg in sporting maneuvers resulting in repetitive stress while the other weaker leg may not be able to effectively absorb forces when called upon to do so. 

What then should young female athletes do to reduce their risk of a very costly ACL rupture?  First of all, all female athletes who compete at a high level must be involved in a structured, sound strength and conditioning program.  The history of female athletics, especially in high schools, has been to just play and not train.  High school weight rooms have traditionally been reserved for and occupied by the football and other male sport athletes.  This must change!  A sound program should first employ a comprehensive evaluation to determine risk of injury.  At DSP, for those female athletes who are in sports that are at risk for ACL tears, basketball, volleyball, soccer, and field hockey, we determine lower body control in a variety of tests and identify the level of possible imbalance between the quads and hamstrings and between the left and right legs.  Nearly all of the female athletes we have tested demonstrate improper landing mechanics from jumps of varying heights.  This is critical especially in light of studies which have found that for female basketball players the greatest incidence of injury occurs in rebounding. 

Next a program must be developed to

aid in teaching proper postural control that will result in athletes’ being able to avoid inward movement and rotation of the knees and proper recruitment of their hamstring muscles when jumping, landing from jumps, and cutting.  Concurrently, the program must address lower body development, especially strength in the posterior chain: gluteals and hamstrings.  A study conducted in 1999 with approximately 1300 high school female and male athletes demonstrated the benefits of such training.  The group of female athletes’ who were involved in a training program throughout their seasons, basketball, volleyball, and soccer, reduced their incidence of serious knee injuries by 62% when compared with female athletes who did not train in-season

 The importance of off the field, court, ice etc. training for female athletes cannot be emphasized enough.  High school weight rooms should be dominated by female athletes and not shied away from which has been so often the case in the past.  Reduce the risk of a catastrophic injury by getting involved in a sound strength and conditioning program and train year-round, not just before the season.  The benefits of not only injury prevention, but also performance enhancement, self-esteem, and a healthy lifestyle are immeasurable!

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