ACL Tears: Can We Prevent Them?
By: Richard Gardner, PT, DPT: Board Certified Clinical Specialist in Orthopaedic Physical Therapy
Fall is in the air. Temperatures are falling, leaves are changing, and football fields across the country are in full gear of the season. In Razorback country we have a newfound love for our team that we have not felt in many years. Along with this amazing sport that draws so much passion, is a high risk of injury. Every year we hear about athletes that have season ending ACL tears. As a result, their athletic career can make a dynamic change and full recovery is a challenge. It is estimated that 100,000-200,000 ACL tears occur every year in the US. According to research, female athletes are more likely to tear their ACL than males. In addition, risk of a second tear can be up to 29% if a young athlete (under 20) returns to his or her sport. Lastly, most ACL tears are non-contact injuries (Logerstedt, et al., 2017.) Sports with the highest risk of ACL tear are women’s soccer, followed by football and women’s basketball (Joseph, et al., 2013.) Usually when an ACL tear occurs it is an awkward inward rotation/buckle of the knee. If you want to watch a video of an in game moment of an ACL tear click here for a video. https://www.youtube.com/watch?v=JzaKBxTDEN0
Throughout our lives we have heard that the best treatment for disease is prevention. Most issues of health such as heart disease, obesity, or type II diabetes can be prevented with regular exercise. Is it possible to use that same principal to effectively prevent an ACL tear? Can we train our athletes in a way that will give them a statical advantage to avoid injury? Since most ACL tears are not due to a linebacker striking a player at the knee and are non-contact, can we train to avoid dangerous movements? Let’s put on our research geek hat and study what the evidence says.
In 2018 the Journal of Orthopaedic and Sports Physical Therapy published clinical practice guidelines for the effectiveness of exercise programs for ACL prevention (Arundale, et al., 2018.) This set of guidelines complied hundreds of studies to help answer this question. There is an overwhelming support of research that states ACL prevention programs are effective at reducing the risk of ACL tears. However, to prevent injury, one must do specific exercises. Getting into the weight room is important, however, that does not train your body to move correctly for injury avoidance. On review of several of the programs published they all have a common theme of strength training, balance training, and plyometric training. Let’s discuss each of these and the important role they plan on ACL prevention.
Strength training is something every athlete should be doing once they reach an age of serious competition (usually middle school age.) Strength training will not turn you into a body builder but give you the basic requirements of strength to meet the demands of the athlete’s sport of choice. If an athlete is avoiding the weight room, he or she can be increasing the risk of injury during season. Strength training should include exercises that will help athletic performance as well as prevent injury. In regard to ACL tear prevention, a strength training program should focus on hip, quadriceps, and hamstring strength. Of particular importance is the strength in the hip, specifically the hip abductors and external rotators (muscles that over the side of the hip that move your leg to the side.)
Research has shown that weakness in this muscle group can be another risk factor for ACL tear (Khayambashi , Ghoddosi, Straub, & Powers, 2016.) The hip abductor group specifically assists with keeping the knee in midline when running or jumping. It is when the knee crosses midline or shifts inward that risk of injury increases (see photos below.) With proper strength, an athlete can control the “inward” movement of the knee and reduce injury!
Balance training is the body’s ability to maintain balance under certain environments. It is not strength based but depends on neuromuscular activation patterns (nerve activation of muscles.) Just like strength training, it must be exercised to improve. In addition, it has been shown that balance training can help reduce the risk of ACL injuries (Mandelbaum, et al., 2005.) Balance training does not mean that you need to get your yoga pants on, however this is one aspect of balance training, but incorporating a few exercises can go a long way. Some of my personal favorite exercises for balance are shown below. These are not all you need to do, but just a few examples. An athlete should use these exercises as a starting place and progress the difficulty. Any great strength and conditioning coach should be able to assist.
Lastly, plyometric training is high intensity jump and agility training is an important aspect of ACL prevention. These can include agility ladder, cone drills, jump training, and more. This is a common aspect of training for athletes but must not be forgotten about. Of particular importance is evaluation of jump landing. If the knee crosses midline on jump landing this is a particular high risk factor for ACL injury (see the photo below again for reference.)
I know this is the same photo as before but when one lands like the photo above, it is very important to keep the knee away from midline. If you saw the video above, you can see a midline collapse of the knee during the QB shift. Plyometrics is a way for our body to learn how to make quick cuts and avoid injury. If this is not already a part of your training, it needs to be. It puts your body in game speed and combines aspects of strength and balance training.
In conclusion, ACL tears can never 100% be prevented. Statistically they are going to happen to even the most trained athlete. However, one can reduce the risk by being proactive. Being proactive can help you avoid an injury that will end your season and make full return difficult. At Specialized Physical Therapy we can provide expert care for strength, balance, and plyometric training. If you are interested in learning more, please give us a call. If you have torn your ACL and want to ensure the best results to get you back in the game call us to help with your post op recovery. We will get you back to strength, balance, and plyometrics. One last note, and maybe a future blog post, is a question I hear often. Is surgery always required for an ACL tear? The answer to this is, it depends! It depends on age, activity level, and personal choice. The ACL will not heal on its own, but one can train to compensate for the lack of stability. The short answer to this is, if one is an athlete then surgical repair is needed. However, if one is older or is not involved with high speed exercise then repair is not always needed. I will save more information on this on a future blog post but if you are on the fence feel free to email me at firstname.lastname@example.org and I can provide more insight.
Happy Fall Everybody! Thanks for reading.
Arundale AJH, Bizzini M, Giordano A, Hewett TE, Logerstedt DS, Mandelbaum B, Scalzitti DA, Silvers-Granelli H, Snyder-Mackler L. Exercise-Based Knee and Anterior Cruciate Ligament Injury Prevention. J Orthop Sports Phys Ther. 2018 Sep;48(9):A1-A42. doi: 10.2519/jospt.2018.0303. PMID: 30170521.
Joseph AM, Collins CL, Henke NM, Yard EE, Fields SK, Comstock RD. A multisport epidemiologic comparison of anterior cruciate ligament injuries in high school athletics. J Athl Train. 2013;48(6):810-817. doi:10.4085/1062-6050-48.6.03
Khayambashi K, Ghoddosi N, Straub RK, Powers CM. Hip Muscle Strength Predicts Noncontact Anterior Cruciate Ligament Injury in Male and Female Athletes: A Prospective Study. Am J Sports Med. 2016 Feb;44(2):355-61. doi: 10.1177/0363546515616237. Epub 2015 Dec 8. PMID: 26646514.
Logerstedt DS, Scalzitti D, Risberg MA, Engebretsen L, Webster KE, Feller J, Snyder-Mackler L, Axe MJ, McDonough CM. Knee Stability and Movement Coordination Impairments: Knee Ligament Sprain Revision 2017. J Orthop Sports Phys Ther. 2017 Nov;47(11):A1-A47. doi: 10.2519/jospt.2017.0303. PMID: 29089004.
Mandelbaum BR, Silvers HJ, Watanabe DS, Knarr JF, Thomas SD, Griffin LY, Kirkendall DT, Garrett W Jr. Effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. Am J Sports Med. 2005 Jul;33(7):1003-10. doi: 10.1177/0363546504272261. Epub 2005 May 11. PMID: 15888716.