In my previous post, I discussed the current research and concepts with regards to Return to Sport following Anterior Cruciate Ligament Reconstruction (ACLR)… Now it is time to discuss how we, as clinicians, can help to prevent these injuries altogether.

A recent Systematic Review and Meta-analysis of 14 studies and 27,000 participants conducted by Gagnier et al found that neuromuscular and educational interventions appear to reduce the incidence rate of ACL injuries by approximately 50%. Within this systematic review, 109 ACL injuries were prevented; that means 109 athletes will not have to face the unfortunately low return to sport and high re-injury rate associated with ACLR. The first ACL prevention program was published in 1999 by Hewett et al and focused on flexibility, plyometrics, weight training, and emphasized maintaining adequate frontal, transverse, and sagittal plane mechanics throughout each exercise/movement. During this study of 1,263 athletes, there were five non-contact ACL injuries in the untrained female group, one in the untrained male group, and none in the trained female group. This study determined that female athletes who do not undergo neuromuscular training have a 3.6x increased likelihood of sustaining a non-contact ACL injury. Since this initial study, several additional randomized controlled trials have also shown the benefits of injury prevention programs on the incidence of ACL injury (Mandelbaum et al, Gilchrist et al, Olsen et al, Caraffa et al, Myklebust et al, and Petersen et al).

In addition to these randomized controlled trials, there have also been several systematic reviews detailing the benefit of neuromuscular training in the prevention of serious knee injury. The first of which was a meta-analysis conducted in 2006 by Hewett et al of 6 studies investigating prevention programs for female athletes. This analysis found that 4 out of 6 neuromuscular intervention programs significantly reduced knee injury incidence, and 3 out of 6 significantly reduced anterior cruciate ligament injury incidence. Overall, the meta-analysis of these 6 studies demonstrates a significant effect of neuromuscular training programs on anterior cruciate ligament injury incidence in female athletes. Later in 2010, Yoo et al found that the odds ratio of injury prevention was 0.40 with the implementation of a prevention program. Yoo and colleagues also determined through meta-analysis that pre- and in-season neuromuscular training with an emphasis on plyometrics and strengthening exercises was effective at preventing ACL injury in female athletes, especially in those under 18 years of age. Finally, in 2012, Sadoghi et al found an overall risk reduction following the implementation of a prevention program of 52% for female athletes and 85% for male athletes. This coupled with the overall reduction of 50% stated by Gagnier et al shows more than enough reason to suggest the need for widespread usage of injury prevention programs amongst all athletes.

With all of this readily available evidence, surely these programs are being utilized by coaches at all levels, right? Unfortunately, according to a survey of female soccer coaches conducted by Joy et al, only 19.8% of coaches implement an Injury Prevention Program (IPP). Of these coaches who chose to implement an IPP, they did so for injury prevention (93%) as well as performance enhancement (36%). Performance enhancement is what will drive athletes, coaches, and parents toward IPPs – with the added benefit of a decreased likelihood of a catastrophic season-ending injury. Thankfully, the literature is in favor of IPPs with regards to performance enhancement as well. In 2005, Myer et al conducted a study investigating the performance enhancing effects of their injury prevention program. They found significant improvements in 1-Repitition Maximum Bench Press and Squat, Single-Leg Hop Distance, Vertical Jump, and speed in the 9.1 meter dash. This study also showed an overall decreased knee valgus and varus torque during functional movement as an added benefit. While injury prevention is the end goal, performance enhancement is what will bring clients through your doors and will make coaches change their philosophy. It is up to physical therapists, athletic trainers, strength & conditioning coaches, and physicians to bring this information to coaches and players alike. We have the evidence to support the effectiveness of these programs, but we need to take the time to educate those who will benefit most.

All this being said, what makes a successful program? While specific areas of training have not been adequately differentiated in terms of effectiveness, there is a general consensus as to what aspects should be included. These areas include a dynamic warm-up, restoration of proximal stability, proprioceptive training, plyometric training, neuromuscular re-education, strength training, and education. One area cannot be proven more effective than another, however certain qualities of a program have been deemed indicative of an effective program. The first and likely most important quality is patient/client compliance. Wingfield et al recently conducted a cluster randomized controlled trial to evaluate the effectiveness of a neuromuscular warm-up program in preventing acute knee injury in adolescent female soccer players. Not surprisingly, they found that athletes who performed ≥ 1 exercise session per week had a lower rate of ACL injury, severe knee injury, and of any acute knee injury compared to the control group. Additionally, in a systematic review conducted by Sugimoto et al, it was found that incidence rates of ACL injury were lower in studies with high rates of compliance with neuromuscular training than in studies with low compliance rates. So, this begs the question of, “How do we make our athletes compliant?” In my opinion, we must provide a solid, systematic evaluative and progressive program addressing each individual athlete’s deficiencies.

There are several Injury Prevention Programs available from the simple (FIFA 11+, Santa Monica Prevent Injury and Enhance Performance Program, ect.) to the more advanced systematic programs implemented by trained fitness and healthcare professionals. Of the programs available, there are two that appear to encompass all aspects of injury prevention that therapists and/or strength & conditioning coaches should consider implementing. The first of which is the Dynamic Movement Assessment (DMA) developed by Trent Nessler, DPT. The DMA consists of a thorough functional assessment backed-up by the use of video feedback to provide visual input to both athletes and clinicians alike. This allows for detailed understanding of where these faulty movement patterns are stemming from and how these deficits should be corrected. The second program is seemingly simpler, albeit a much more researched program in the Functional Movement Screen (FMS)/Selective Functional Movement Assessment (SFMA). These systems are comprised of several tests that provide the ability to ‘screen’ athletes for the poor movement patterns often associated with increased likelihood of injury. Regardless of the specific system, the key to any successful program is selecting a solid classification system to identify those at risk and implement exercise programs to improve their specific movement patterns and/or deficient muscular performance.

About the Author John Snyder, PT, DPT, OCS, CSCS

I am a Physical Therapist, a Board Certified Orthopaedic Specialist, a Strength & Conditioning Specialist, an Educator, and a Research Junkie. My goal is to provide resources for orthopedic and sports medicine clinicians to keep up to date with the current literature and allow them to translate it to their practice.

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