About the ACL
Injuries and Prevention Strategies
“I have ACL” is a common sentence I hear or overhear from athletes who have a traumatic knee injury and have consulted with an orthopedic specialist.
This may not be the most appropriate statement since everybody has an ACL… two of them, in fact. ACL stands for anterior cruciate ligament which is found in each knee. It is “…one of the strong[est] bands of tissue that help connect your thigh bone (femur) to your shinbone (tibia). ACL injuries most commonly occur during sports that involve sudden stops or changes in direction, jumping and landing — such as soccer, basketball, football and downhill skiing.”1
ACL tears and consequent reconstruction surgeries constitute to about 350,000 in the United States alone.2 The increased incidence of this, especially in athletes, have caused for the development of prevention strategies against this type of injury. Before getting into the specifics of these strategies, let me discuss first what makes certain athletes at high risk for injuring this ligament.
Female athletes, especially in post-pubescent age, have a 2-8x increase in risk of ACL injury. This large difference is due to anatomical, hormonal, and neuromuscular differences between genders. Increased hip to knee angle ratio, greater hip moment and loads versus the knee & predominant quadriceps strength versus hamstring strength, and cyclic fluctuations in hormones leading to laxity contribute to these factors, respectively.
Additional predictions of risk include:3
Knee hyperextension
Decreased hamstring strength
Decreased core strength
Side trunk excursions after perturbations (trunk strategy is used during balance training)
Decreased balance
Limb asymmetry*
History of back pain
Previous ACL injury.
These are of course assessed properly and accurately by a health professional. These risk factors are therefore what prevention strategies should include. Taking a step back, a prevention program should include three components: plyometrics, neuromuscular training, and strength training. Specifics of these components are usually implemented by a health professional, strength and conditioning coach, and/or athletic trainer. However, another study4 found that the FIFA 11+ Injury Prevention Program seems to yield a decreased number of injury rates when a non-medical professional is not present. (I know this makes things confusing)
Click here for the FIFA 11+ Injury Prevention Program: https://www.yrsa.ca/wp-content/uploads/2019/11/pdf/Fifa11/11plus_workbook_e.pdf
In conclusion, ACL injuries have increased in incidence especially in athletes. Therefore, prevention strategies need to be implemented. However, a great injury prevention program is the first step.
Starting athletes young, lessening knee valgus (inward) moment during activity, compliance (self-explanatory), dosage of 20-30 minutes several times a week), type of feedback from health professionals, and exercise variety are six important principles to successfully carry out any injury prevention program. This applies to everyone, not just athletes. So, check if your exercise program includes plyometrics, neuromuscular training, and strength training. Next step: implement the six principles. (Regarding age, it’s always better to start now than later.)
I hope this helps you 💡, and I hope to see you in the next session 😏
Isabel
Nessler, T., Denney, L., & Sampley, J. (2017). ACL injury prevention: What does research tell us? Current Reviews in Musculoskeletal Medicine, 10(3), 281–288. https://doi.org/10.1007/s12178-017-9416-5
Hewett, T. E., Myer, G. D., Ford, K. R., Paterno, M. V., & Quatman, C. E. (2016). Mechanisms, prediction, and prevention of ACL injuries: Cut risk with three sharpened and validated tools. Journal of Orthopaedic Research, 34(11), 1843–1855. https://doi.org/10.1002/jor.23414
Silvers-Granelli, H. J., Bizzini, M., Arundale, A., Mandelbaum, B. R., & Snyder-Mackler, L. (2017). Does the FIFA 11+ Injury Prevention Program Reduce the Incidence of ACL Injury in Male Soccer Players?. Clinical Orthopaedics and Related Research, 475(10), 2447–2455. https://doi.org/10.1007/s11999-017-5342-5