Updated: May 2
Every athlete's biggest fear, injuring their anterior cruciate ligament (ACL). In this article, I will explain the scientifically proven way to best avoid it.
This is one of the most common and potentially debilitating injuries in soccer and often prevents athletes from being able to play the game again. Once an athlete suffers from an ACL injury, they are at a much higher risk for re-injury, or other knee injuries (Gottlob et al., 2016).
The ACL originates from the posterior aspect of the femur (thigh bone) and inserts into the anterior aspect of the tibia (shin bone). This arrangement allows the ACL to stabilize the knee joint and prevent excessive forward movement of the tibia relative to the femur.
So why are ACL injuries so common in the sport? Here are a few reasons highlighting why...
Movements: sudden change of direction, starts, stops, jumps and landings placing stress on the knee joint. Not all ACL injuries are contact, poor landings often lead to injury.
Contact: Collisions between players when going for tackles
Playing surface: Not every pitch is created equally, uneven and unpredictable surfaces on grass can lead to awkward landings/falls.
Gender differences: Female soccer players are two to six times more likely than male soccer players to suffer an ACL injury (Hewett et al., 2005).
So why are females more prone to ACL injuries than males? Here are a few reasons
Wider pelvis: Females tend to have wider pelvises than males, which can create a larger angle between the thigh bone (femur) and shin bone (tibia). This wider angle, known as the Q angle, can put more stress on the knee joint and increase the risk of ACL injury (Hewett et al., 2006).
Hormonal changes: The menstrual cycle can cause hormonal changes that affect ligament laxity, or the looseness of ligaments. During certain phases of the menstrual cycle, estrogen levels are higher, which can increase ligament laxity and make the ACL more vulnerable to injury (Lebrun et al., 2018).
Smaller ACL size: Females tend to have smaller ACLs than males, both in terms of size and cross-sectional area. This smaller size can make the ACL more susceptible to injury (Prodromos et al., 2007).
Landing mechanics: Females tend to land from jumps and other movements in a way that places more stress on the knee joint than males. Specifically, females tend to land with their knees straighter and their feet more turned inward, which can increase the risk of ACL injury (Myer et al., 2006).
Nordic hamstring curls are an effective exercise that all soccer players should be doing. Specifically, they target the hamstrings, which are crucial for knee stability and ACL injury prevention (Van Der Horst et al., 2015). One exercise is not going to completely eliminate the possibility of getting injured, but strength training is a preventative measure that can reduce risk.
The exercise involves lowering your body slowly and under control from a kneeling position, using your hamstrings to resist gravity. Here's a quick overview of how to perform it:
It is important to focus on training the eccentric (going down) phase of this exercise, as it places greater stress on the hamstrings to handle the forces of decelerating the knee during high-speed movements such as cutting and jumping (Al Attar et al., 2016). The eccentric phase places greater time under tension on the hamstring, and leads to greater muscle adaptation and strength gains.
Here is a video demonstrating how to effectively perform the eccentric phase of the exercise:
The concentric (up) phase, trains your hamstrings to produce force, necessary for explosive movements like sprinting and jumping. Here is a variation that you can use with a resistance band to train the concentric phase. After completing the reps of the concentric phase, you should still continue to max out the eccentric phase without the resistance band and support yourself up.
Thank you for reading! Feel free to reach out with any questions.
Al Attar, W. S. A., Soomro, N., Sinclair, P. J., Pappas, E., & Sanders, R. H. (2016). Effect of injury prevention programs that include the Nordic hamstring exercise on hamstring injury rates in soccer players: a systematic review and meta-analysis. Sports Medicine, 46(6), 803-817.
Gottlob, C. A., Baker, C. L., & Pelland, L. (2016). Anterior cruciate ligament injuries in soccer: Loading mechanisms, risk factors, and prevention programs. Journal of Sport Rehabilitation, 25(2), 129-141.
Hewett, T. E., Ford, K. R., & Myer, G. D. (2006). Anterior cruciate ligament injuries in female athletes: Part 2, a meta-analysis of neuromuscular interventions aimed at injury prevention. The American Journal of Sports Medicine, 34(3), 490-498.
Hewett, T. E., Myer, G. D., & Ford, K. R. (2005). Anterior cruciate ligament injuries in female athletes: Part 1, mechanisms and risk factors. The American Journal of Sports Medicine, 33(3), 1579-1601.
Lebrun, C. M., McKenzie, D. C., Prior, J. C., & Taunton, J. E. (2018). Effects of menstrual cycle phase on athletic performance and injury risk. Current Sports Medicine Reports, 17(8), 266-271.
Myer, G. D., Ford, K. R., & Hewett, T. E. (2006). The effects of gender on quadriceps muscle activation strategies during a maneuver that mimics a high ACL injury risk position. Journal of Electromyography and Kinesiology, 16(6), 680-688.
Prodromos, C. C., Han, Y., Rogowski, J., Joyce, B., & Shi, K. (2007). A meta-analysis of the incidence of anterior cruciate ligament tears as a function of gender, sport, and a knee injury–reduction regimen. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 23(12), 1320-1325.
Van Der Horst, N., Smits, D. W., Petersen, J., Goedhart, E. A., & Backx, F. J. (2015). The preventive effect of the nordic hamstring exercise on hamstring injuries in amateur soccer players: a randomized controlled trial. The American Journal of Sports Medicine, 43(6), 1316-1323.