New Perspectives on ACL Injury Prevention

Anterior cruciate ligament (ACL) injuries are among the most common injuries in sports.

ACL injuries are most often caused by movements that involve jumping, cutting, and pivoting. In the past, ACL injury prevention was based on strengthening the muscles that support ligaments and enhancing basic neuromuscular control; however, current research is focused on a newer, multifaceted approach that includes traditional aspects of strength training along with neuromotor training, but also includes modernized elements like wearable technologies, data analytics, and customized programs. 

Related course: ACL Injury, Surgery, and Rehabilitation: A Science-Based and Evidence-Informed Approach 

Neuromuscular training 

Neuromuscular training uses principles of motor learning and control to train the brain to optimize muscle activation patterns during movement. Training neural synchronization and coordinated muscle activation and deactivation patterns reduces the stress on the ACL. 

Plyometric training 

Plyometric training uses hopping and jumping exercises like jump squats, one-legged hops, and other high-impact drills that can prepare structures, like the knee, to better absorb and redirect forces. 

Movement pattern re-education 

Sometimes movement patterns are incorrect, like knee valgus or inward collapse during a squat or increasing hip flexion during landing, and this can lead to injury. Re-teaching proper exercise mechanics redistributes forces on ligaments and can reduce ACL strain. 

Proprioception 

Proprioception, or the ability to know where the body is in space, is one of the most important components of injury prevention. Training drills that improve spatial awareness can help athletes recover quickly from unexpected movements that could lead to injury if not corrected in real time. 

Balance 

Balance training is essential to performance and injury prevention. Exercises that challenge balance can enhance stability around the knee. Suggested techniques include using stability boards and foam pads that create unstable surfaces during traditional strength training exercises. Boards and pads work by increasing motor stimulation during exercise and improve proprioceptive feedback during movements. 

Individualized prevention protocols 

Advances in technology allow for more personalized injury prevention programs. Rather than using one model for everyone, athletes have specialized training programs according to their unique movement patterns. 

Biomechanical assessments 

Biomechanical assessments are a good start place for a customized training program. Assessments capture movement patterns using tools like force plate systems that allow trainers to evaluate deficits in movement, such as knee valgus or hip adduction. 

Poor movement patterns put athletes at a higher risk for ACL injuries, and by using a combination of biomechanical assessment tools and then corrective exercises, dysfunctional movement patterns can be identified and corrected. Corrective exercises improve movement mechanics within an athlete's kinetic chain, therefore reducing the likelihood of injury. 

Hormonal factors 

Hormonal factors can predispose an athlete to ACL injury. For example, females are more prone to ACL injuries due to anatomical, hormonal, and neuromuscular factors. Thus, female-specific training approaches are necessary. Distinct phases of the menstrual cycle can affect the risk of injury since during different hormonal phases, there is a change in ligament laxity. Custom programs that that align with hormonal fluctuations and how those changes affect structures should be considered for female athletes. 

Wearable technology 

Wearable technology has the potential to reduce the likelihood of ACL injury. It can provide direct and custom feedback to the athlete regarding their individual movements. Wearables can serve to guide interventions in technique, force distribution, and fatigue. 

Devices that track motion and provide feedback on joint angles, landing mechanics, and gait patterns can help athletes adjust their movements during training and performance that directly impacts the likelihood of ACL injury. 

Training load and overtraining 

Excessive training load and overtraining are known risk factors for injury. Training volume, intensity, and frequency need to be managed along with recovery strategies to ensure injury prevention. Structuring training phases in relation to the off-season, pre-season, and in-season, i.e., using periodization training methods, can also lower the risk of overuse injuries.  

The inclusion of measures of fatigue through wearable technology, which monitor known indicators of overtraining like heart rate can ensure athletes are not training or competing in a fatigued state that increases their vulnerability to ACL injuries. 

ACL injury prevention is constantly evolving. From traditional techniques to more sophisticated, personalized, technology-based methods, injury prevention and management will continue to change.  

Athletic trainers need a multifaceted approach to ACL injury prevention that includes traditional strength and neuromuscular training along with individualized biomechanics analysis and programming. By combining strength and conditioning, optimized movement pattern training, and the latest technology tools to design custom programs, ACL injuries can be prevented. 

To learn more about ACL injury prevention, visit Project Play.