Reducing The Risk of ACL Injuries

March 17th, 2017

Check out this list of impressive athletes:  Heather Mitts, Lamar Miller, Carson Wentz, Tom Brady, Klay Thompson, Brandi Chastain, Robert Pires, Alex Morgan, and Mikel Arteta.

What do they all have in common?  Aside from them all being amazing soccer players that have made it to the pinnacles of their sport, they have all suffered Anterior Cruciate Ligament injuries.  In some cases multiple times!  This list can certainly be expanded upon with thousands of others from youth to world class players who have the unfortunate bond of suffering an ACL injury.

The prevalence of injury to the ACL among athletes is on the rise.  Over 200,000 reconstructions are performed in this country each year.  Millions of dollars are spent on surgery, rehabilitation, recovery and research related to ACL injuries.  Fortunately, the research within the sports medicine community is beginning to find answers to this epidemic with a solution to reduce the risk of injury.   The challenge for sports medicine professional is to get the word out and encourage athletes, coaches and parents to participate in these injury prevention programs.

Background on ACL Injuries

The mechanism of an ACL injury can be categorized as “contact” or “non-contact.”  “Contact” ACL injuries occur when there is an external force applied to the athlete’s lower extremity or a collision.  “Non-contact” ACL injuries occur without an external force applied to the lower extremity.  “Non-contact” injury mechanisms are often described as occurring when the athlete plants their foot while making a change of direction, such as making a quick lateral move to evade a defender or defend an opponent.  Or they might describe landing awkwardly from a jump, feeling a “pop” in their knee, and collapsing to the ground.  These non-contact injuries account for over 70% of the ACL tears and are the ones that can be reduced.  While this type injury affects both genders across many sports, current research shows the incidence of this injury to be much greater in females, and specific sports such as soccer and basketball.

Many factors have been proposed to explain the phenomenon of females being 2 to 8 times more likely to suffer an ACL injury in sports.  Among these factors are anatomical differences between genders, such as females’ having smaller ACL’s as well as smaller notches in the knee where the ACL resides.  Females typically have steeper angles from their hip to their knee which gives them a more knock-kneed alignment and increases the valgus stress at the knee.  There are also suggestions that hormonal differences may contribute to the injury discrepancy between genders.

There are also biomechanical and neuromuscular differences between genders that may increase ACL injury risk for females.  Female athletes have been shown to have different landing and cutting mechanics, and different muscle firing patterns compared to males, which alter the forces at the hip and knee.  These injury risk factors though more prevalent among females, are also found in males.  These characteristics are so important to recognize because they are modifiable with proper training to reduce the risk of injury!

Reducing Injury Risk

While public awareness about the risks associated with ACL injuries has certainly improved, there remains a large void among athletes, coaches, and parents who are not pro-active in helping to reduce the incidence of these injuries.  The evidence and resources to help reduce these injuries are readily available and need to be more widely administered.

There is significant research out there in the sports medicine community providing evidence that supports the use of exercise programs to reduce the incidence of ACL injuries.  Multifaceted programs that include strength training, proprioception and neuromuscular training, plyometric training, and movement skill training (jumping and landing mechanics, change of direction technique, etc…) demonstrate the most success.  These programs should be age appropriate based on the developmental age of the athlete and properly supervised by a qualified professional.

Some coaches have implemented protocols suggested by various published ACL prevention programs to their teams practice schedules which is a big step in the right direction.  More of this needs to happen starting at the youth level.  Kids need to learn proper jumping, landing, cutting/pivoting, and agility techniques.  These are skills that are not often taught at soccer, basketball and lacrosse practice.  Basic movement patterns should be developed with proper mechanics to help minimize the risk of injury, not just to the ACL but to the entire body.  Body weight strength and neuromuscular control exercises that reinforce the proper movement patterns should be incorporated into every athletes warm up, practice and training sessions to allow the athlete to replicate these movements day in and day out.  This is the basis of a proper injury prevention program.  The scientific literature describes options for ACL injury prevention programs to be done on the field with the team, at home for each individual athlete or in a training facility that implements an injury prevention program.  The key is participating in one and adhering to it throughout the athlete’s athletic career.