Women's Football Hub

Written by: Nicholas Maffetone, SPT; Matthew Weller, SPT

Edited by: Anne Leung PT, DPT

What Is The ACL?

ACL stands for Anterior Cruciate Ligament, which is one of the main stabilizers of the knee. An ACL injury can happen through either a contact or a non-contact injury and is quite common in women’s and girls’ football. If the ACL is fully torn, an athlete will typically need surgery to reconstruct the ligament and re-stabilize the knee, followed by extensive rehab. A secondary ACL injury occurs when an athlete injures their ACL after having a reconstruction surgery. This can occur on the surgical side or the opposite side.

What Are Risk Factors For Injury?

Unfortunately, having a previous ACL tear is a major risk factor for another ACL tear.(9,11) Female athletes are also 2-8 times more likely to tear their ACL than male athletes.(13) Risk factors fall into two categories: modifiable and non-modifiable. You can’t change whether you’ve already had an ACL injury or if you are biologically female, these are non-modifiable risk factors. Modifiable risk factors are things you can actively work on to decrease your risk of injury. In particular, these include getting involved in a prevention program, muscle strength and when you return to the sport you play.(1,2,4,10)

What Can We Do To Prevent Them?

There are four main parts of prevention for secondary injury after you’ve torn your ACL. Timeline, strength, movement quality, and confidence.

1. Timeline. When you return to sport after an ACL surgery is really important and a possible risk factor for another injury. At a minimum, researchers recommend waiting until 9-12 months to return to sport significantly decreases your risk for a secondary ACL injury.(1,2,10)

2. Strength. Most importantly, the strength of your quadriceps muscles. The quadriceps are the main mover of the knee joint and weaken significantly after ACL surgery. Research shows getting your quadriceps strength to 90% of your nonsurgical side will help to decrease the risk of a secondary ACL tear. Hamstring strength symmetry is also really important, but this is usually easier for athletes to restore than quadriceps strength.(2) Female athletes have lower quadriceps strength than male athletes after ACL surgery, so it is even more important for females to continue strengthening during their rehab form ACL surgery.(5–7)

3. Movement Quality. Your movement patterns can place more stress on ligaments like your ACL or on your muscles. Using your muscles for stability is better for reducing likelihood of injury. After ACL surgery it is common to shift movement patterns so that the leg that had surgery doesn’t have to work as hard but this may put you at additional risk for a second injury.(3) It is important to work with trained Physical Therapists and Coaches to help you accurately re-train your movement patterns.

4. Confidence. Research shows athletes who are fearful are more likely to suffer a secondary ACL injury AND athletes who are overly confident after ACL surgery are more likely to suffer a secondary ACL tear.(8,12) The ideal amount of confidence is not yet known, but athletes should understand the risks of returning to sport and the importance of prevention/maintenance exercise. It’s also important to address fear of movement or fear of secondary injury, either with physical therapists or mental health professionals.

Together, these pieces can help to decrease the risk of injury. While it is impossible to fully eliminate the risk of a secondary ACL tear, understanding and addressing these risk factors can help athletes come back stronger and safer.

Real-Life Take-aways

1. Train safe and endure high quality movements with help from a professional.
2. Take your time- coming back from an ACL injury can take 9 months-1 year or longer.
3. Strength train for the lower extremity/core muscles throughout your rehab process after surgery.
4. Trust your training and listen to your limits.

For more information see our webinar below

References

1.       Beischer, S, Gustavsson, L, Senorski, EH, et al. Young athletes who return to sport before 9 months after anterior cruciate ligament reconstruction have a rate of new injury 7 times that of those who delay return. Journal of Orthopaedic and Sports Physical Therapy 50: 83–90, 2020.

2.       Grindem, H, Snyder-Mackler, L, Moksnes, H, Engebretsen, L, and Risberg, MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: The Delaware-Oslo ACL cohort study. British Journal of Sports Medicine 50: 804–808, 2016.

3.       Huang, Y-L, Chang, E, Johnson, ST, et al. Explosive Quadriceps Strength and Landing Mechanics in Females with and without Anterior Cruciate Ligament Reconstruction. Int J Environ Res Public Health 17: 7431, 2020.

4.       Johnson, JL, Capin, JJ, Arundale, AJH, et al. A Secondary Injury Prevention Program May Decrease Contralateral Anterior Cruciate Ligament Injuries in Female Athletes: 2-Year Injury Rates in the ACL-SPORTS Randomized Controlled Trial. J Orthop Sports Phys Ther 50: 523–530, 2020.

5.       Kneebone, L, Edwards, P, Blackah, N, et al. Sex-based differences in physical and psychological recovery, and return to sport, following anterior cruciate ligament reconstruction. Knee 52: 22–31, 2025.

6.       Kuenze, C, Lisee, C, Pfeiffer, KA, et al. Sex differences in physical activity engagement after ACL reconstruction. Phys Ther Sport 35: 12–17, 2019.

7.       Leung, A, Kantak, S, Hammoud, S, Abraham, R, and Zarzycki, R. Sex differences in corticospinal excitability and quadriceps performance after anterior cruciate ligament reconstruction. Journal Orthopaedic Research jor.25725, 2023.

8.       McPherson, AL, Feller, JA, Hewett, TE, and Webster, KE. Psychological Readiness to Return to Sport Is Associated With Second Anterior Cruciate Ligament Injuries. Am J Sports Med 47: 857–862, 2019.

9.       Paterno, MV, Rauh, MJ, Schmitt, LC, Ford, KR, and Hewett, TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med 42: 1567–1573, 2014.

10.      Van Melick, N, Van Cingel, REH, Brooijmans, F, et al. Evidence-based clinical practice update: Practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. British Journal of Sports Medicine 50: 1506–1515, 2016.

11.      Wiggins, AJ, Grandhi, RK, Schneider, DK, et al. Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis. Am J Sports Med 44: 1861–1876, 2016.

12.      Zarzycki, R, Cummer, K, Arhos, E, et al. Female Athletes With Better Psychological Readiness Are at Higher Risk for Second ACL Injury After Primary ACL Reconstruction. Sports Health 16: 149–154, 2024.

13.      The female ACL: Why is it more prone to injury? J Orthop 13: A1–A4, 2016.