Your new client, 16-year-old Alexis, is a competitive athlete who wants you to design a fitness program that will help her prevent a second anterior cruciate ligament (ACL) tear. She partially tore her ACL while playing soccer and rehabbed it with a physical therapist, who cleared her to play again. Alexis returned to spring softball without an issue, but she would like to be as fully prepared as possible for the upcoming fall soccer season. She hopes to be recruited to play in college, but her parents are concerned she will sustain another ACL injury, perhaps a more severe one.

ACL tears are among the most common orthopedic injuries in the United States (Silvers & Mandelbaum 2007). Fitness professionals are uniquely positioned to assist clients like Alexis who may be at risk for, or are recovering from, ACL injury, as many fit pros are already engaged with at-risk populations at their studios, health clubs or training centers. This article reviews details about ACL injury prevention and diagnosis, risk factors, injury management, and personal training program design.

Anatomy of the ACL

The ACL provides the knee joint with stability and rotational control during movement. The ligament is located on the lateral femoral condyle (on the femur) and runs anteriorly to its insertion site on the tibia. It provides the primary restraint against anterior tibial translation, in addition to the rotational stability important in pivoting and cutting. ACL injury often results from noncontact pivoting, twisting or cutting or from a jump landing, for example, while rebounding (Bronstein & Schaffer 2017). Individuals commonly report hearing or feeling a “pop” at the time of injury, followed by localized swelling at the knee joint.

Preventing an ACL injury, in addition to staving off recurrence, is important to the knee joint’s long-standing health. If an athlete sustains a second ACL injury and must undergo a revised reconstruction, there is significantly more chondral (cartilage) damage (Mitchell et al. 2017). To add insult to injury, the prevalence of osteoarthritis (OA) after ACL reconstruction significantly increases over time (Cinque 2017).

ACL Injuries and Gender

Prevention isn’t always possible. Certain sports, such as soccer and basketball, have higher incidences of ACL injury owing to the frequent cutting, pivoting and decelerations required to play competitively (Boden et al. 2010).

Gender is also believed to play a large role in ACL injury risk, especially in the athletic, adolescent population. Female athletes experience a higher incidence of ACL rupture than their male peers across multiple sports (Boden et al. 2010).

Many modifiable and nonmodifiable risk factors influence this higher incidence. Nonmodifiable factors include anatomy (smaller intercondylar notch width, for instance). Additionally, it’s been hypothesized that reproductive hormones play a role, with some research suggesting that a shift in estrogen and progesterone levels may increase ACL injury susceptibility (Hewett, Myer & Ford 2006). However, consensus is lacking on the relationship between the menstrual cycle and ACL injuries.

Modifiable risk factors include neuromuscular control, strength and landing mechanics (Boden et al. 2010). Specifically, there are gender differences found in motion patterns and the forces generated from the hip and trunk to the knee. Females may have weaker hip extensors, which necessitates using hip flexor muscles for trunk control over the hips during jump landing. This posture results in a more upright hip position and an altered knee angle upon landing (Hewett et al. 2005). To combat this difference, strengthening programs that emphasize hip control—closed-chain gluteal and hamstring activation—have proved to be beneficial in ACL injury prevention (Hewett et al. 1999).

Injury Management

Fitness professionals are in an ideal position to help clients prevent an ACL injury. In fact, ACL injury prevention programs are becoming a preparatory mainstay for sports and recreation with today’s active adolescents and adults. ACL injuries can lead to OA and injury in the knee cartilage. Timely referral and treatment are therefore critical. Given the potentially long-term, significant impact of an ACL injury, a proper program is vital.

Those who are already vulnerable to injury (females or those in high-risk sports) are particularly likely to see marked reduction in their risk when engaged in such programs. Since some risk factors are nonmodifiable (gender, for example), the focus has to be on those factors that can be modified, such as neuromuscular control. Maximizing strength, neuromuscular control and technique are the main goals of a program, and visual and verbal feedback are key to gauging a client’s success. Ideally, to prevent bad habits setting in early, ACL prevention programs are best initiated at or prior to the onset of puberty, and at least 6 weeks before the athletic season starts, with a maintenance program during the season.

For a program to strengthen the body to prevent ACL injuries, please see “Programming to Prevent ACL Injury” in the online IDEA Library or in the April 2018 print edition of IDEA Fitness Journal. If you cannot access the full article and would like to, please contact the IDEA Inspired Service Team at 800-999-4332, ext. 7.