Protecting Your Daughter from ACL Injuries: Understanding the Factors and Importance of Training
By Emily Neff (Pappas), Ph.D. student
As a parent, you want the best for your daughter, especially regarding her sports performance and well-being. One area of concern for female athletes is the risk of anterior cruciate ligament (ACL) injuries. Research has shown an increasing incidence of ACL injuries among female athletes, particularly during adolescence. To protect your daughter from these injuries, it is crucial to understand the complex factors involved and the importance of training.
This article aims to provide parents with valuable insights into ACL injuries and highlight the significance of injury prevention strategies.
Anatomical Factors
Numerous studies have explored anatomical factors such as Q-angle (a measure of knee alignment) and femoral notch size.
However, the findings remain inconclusive and inconsistent.
Recent studies have not found significant differences in these measures between female athletes with ACL injuries and those without (Kızılgöz et al., 2018; Huegel et al., 1999)
Some girls have wider hips, and some girls don’t…..but wider hips are NOT related to ACL injury rates.
The relationship between femoral notch size and ACL injuries is also complex, with factors like height and body mass potentially playing a role in ACL size and load tolerance (Chandrashekar et al., 2005).
However, recent studies have shown that muscle strength is more related to ACL size than femoral notch size (Beaulieu et al.,2021).
Female athlete strength levels may be more related to ACL size than her Q-angle and femoral notch size.
It is clear that anatomical factors alone do not fully explain the higher incidence of ACL injuries in female athletes.
learn more on ACL & Anatomy HERE
Hormonal Factors
Hormonal influences, including estrogen levels, ligament laxity, and menstrual cycle irregularities, have been investigated in relation to ACL injuries.
However, the relationship is not fully understood.
Some studies suggest that changes in estrogen levels and hormonal fluctuations may affect ligament laxity, while others contradict these findings.
In fact, recent studies have concluded “ it is inconclusive whether aparticular MC phase predisposes women togreater non-contact ACL injury risk based on neuromuscular and biomechanical surrogates” (Dos’Santos et al., 2023).
The timing of ACL injury peaks during early puberty further complicates the hormone hypothesis.
During puberty, your athlete’s estrogen levels are not yet fully cyclical. In fact, 50% of her cycles do not have high enough peaks of estrogen to drive ovulation (American, 2016). However, this period is linked to higher ACL injuries.
Limited research exists on the effects of estrogen levels, ligament laxity, and growth-related factors in adolescent female athletes.
Recent studies show that changes in growth, rather than estrogen, drive ligament changes in the female athlete (Wild et al., 2013; Wild et al., 2017).
Rather than hormonal changes, growth changes seem to influence ACL injury rates in female athletes.
Hormonal factors alone do not completely explain the disparity between the sexes in ACL injury.
learn more on ACL injuries and hormones HERE
Kinematic (Movement) Differences
Clear kinematic differences exist between males and females during pubertal development, contributing to the higher incidence of ACL injuries in female athletes.
Changes in landing mechanics, increased knee valgus motion, and inadequate muscle strength and control are observed in female athletes after puberty (Hewett et al., 2004).
Girls and boys grow differently, with boys experiencing a neuromuscular spurt while girls do not.
Without this spurt, girls become “ligament dominant” in their movements, leading to more impact on their knee ligaments and less on their muscles. (Hewett et al., 2002)
However, these kinematic differences decrease with training experience, suggesting that training can mitigate these differences.
Girls and boys with SIMILAR strength and training experience show SIMILAR movements in jump, landing, and cutting tasks (Medina et al. 2008; Orishimo et al., 2009).
Neuromuscular training interventions have positively improved movement patterns and decreased injury risks in female athletes.
With training, girls are NOT destined to tear their ACLs!!
The Role of Neuromuscular Training
Neuromuscular training, including plyometric and strength exercises, has been shown to positively influence movement patterns and decrease ACL injury risks in female athletes.
These training programs improve muscle firing patterns, dynamic joint stability, and movement pattern efficiency.
Recent studies show that incorporating strength training in ACL injury prevention programs is crucial for reducing injury rates (Mattu et al., 2022).
McQuilliam et al. (2022) found that initiating strength and conditioning training before the peak height velocity can enhance strength and power development and reduce the risk of injuries.
Unfortunately, females are not exposed to higher intensity and higher technical neuromuscular training programs to the same extent as boys.
Recent studies highlight disparities in training methods, such as fewer in-season strength and conditioning sessions compared to boys and less frequent use of weightlifting movements (OWL) and free weights for female athletes (McQuillium et al., 2022)
Addressing Disparities and Promoting Strength Training
There is a significant disparity in the prioritization and implementation of strength training practices between male and female athletes.
Early exposure to strength training and educating coaches and athletes about its importance can help address these disparities.
Strength training during adolescence can decrease ACL injury risk in female athletes and promote long-term adherence to training (Mattu et al., 2022).
Early exposure to higher technical movements such as Olympic Weightlifting (OWL) may also enhance interest in strength training among female athletes and improve outcomes in ACL injury prevention.
This is especially true as improvements in technique, rather than intensities, have been found to motivate female athletes in the weightroom (Barker et al., 2018).
(and something we have found over the past 8 years at Relentless, working only with female athletes!)
Making Time for Training
Decreasing ACL injury risks DEPEND on your ability to prioritize strength training for your female athlete.
But we get it, with year-long sports, there is only so much time in a day!
For many of you, schedules may look like this during the school competitive season:
Monday- School Practice (2hrs)
Tuesday- School Practice (2hrs) + Club Practice (2hrs)
Wednesday- School Game (2hrs) + Skills Practice (1hr)
Thursday- School Game (2 hrs) + Club Practice (2 hrs)
Friday- School Practice (2 hrs) + Skills Practice (1hr)
Saturday- School Game (2 hrs)
Sunday- Club Practice (3 hrs)
If you add up all these hours, your daughter is participating in sport for 20-25hrs per week. This is a part-time job!
So how do you fit in training?
Consider that you are exposing your athlete to 20-25 hours of the SAME STRESS (sport), even if they are different sports (soccer & softball). This BREAKS THE BODY DOWN!!
As a parent, it is your job to SELECT what sports practices she participates in and to PRIORITIZE her HEALTH and DEVELOPMENT beyond competitive play.
For at least 6 months of the year, research shows engaging in just 2-3 hours of resistance training will help reduce your daughter’s risk of an ACL injury by 65% (Dahab & McCambridge, 2009)
So how can we fit that in?
Consider this NEW schedule during the school season:
Monday- School Practice (2hrs) + Strength Training (1hr)
Tuesday- School Practice (2hrs) + Club Practice (2hrs)
Wednesday- School Game (2hrs) + Skills Practice (1hr)
Thursday- School Game (2 hrs) + Club Practice (2 hrs)
Friday- School Practice (2 hrs) + Skills Practice (1hr) + Strength Training (1hr)
Saturday- School Game (2 hrs)
Sunday- Club Practice (3 hrs) REST DAY!!
With this new schedule, your athlete is down to 19 hours of sport and 2 hours of strength AND A REST DAY (which is IMPERATIVE for recovery) and reducing ACL injury risks!
Conclusion
Reducing ACL injury risk in female athletes requires a comprehensive understanding of the complex factors contributing to these injuries.
While anatomical and hormonal differences exist, kinematic differences play a significant role during pubertal development.
Incorporating neuromuscular training, including plyometrics and strength exercises, is essential in improving movement patterns and decreasing ACL injury risks.
Addressing disparities and promoting early exposure to strength training, including higher technical modalities such as OWL, are crucial for reducing ACL injury rates and ensuring the long-term well-being of female athletes.
By prioritizing injury prevention strategies and providing the necessary support, we can empower female athletes to thrive in their sports while minimizing the risk of ACL injuries.
References
American Academy of Pediatrics, Committee on Adolescence, American College of Obstetricians and Gynecologists, & Committee on Adolescent Health Care. (2006). Menstruation in girls and adolescents: Using the menstrual cycle as a vital sign. Pediatrics, 118(5), 2245–2250. https://doi.org/10.1542/peds.2006-2481
Barker, K., Sargent, D., Lloyd, R. S., Lucy Kember, Radnor, J. M., & Oliver, J. L. (2018). Training young female athletes. In Strength and conditioning for female athletes (pp. 171–189). The Crowood Press.
Beaulieu, M. L., DeClercq, M. G., Rietberg, N. T., Li, S. H., Harker, E. C., Weber, A. E., Ashton-Miller, J. A., & Wojtys, E. M. (2021). The anterior cruciate ligament can become hypertrophied in response to mechanical loading: A magnetic resonance imaging study in elite athletes. The American Journal of Sports Medicine, 49(9), 2371–2378.https://doi.org/10.1177/03635465211012354
Chandrashekar, N., Slauterbeck, J., & Hashemi, J. (2005). Sex-based differences in the anthropometric characteristics of the anterior cruciate ligament and its relation to intercondylar notch geometry: A cadaveric study. The American Journal of Sports Medicine, 33(10), 1492–1498. https://doi.org/10.1177/0363546504274149
Dahab, K. S., & McCambridge, T. M. (2009). Strength training in children and adolescents: raising the bar for young athletes? Sports Health, 1(3), 223–226. https://doi.org/10.1177/1941738109334215
Dos’Santos, T., Stebbings, G. K., Morse, C., Shashidharan, M., Daniels, K. A. J., & Sanderson, A. (2023). Effects of the menstrual cycle phase on anterior cruciate ligament neuromuscular and biomechanical injury risk surrogates in eumenorrheic and naturally menstruating women: A systematic review. PLOS ONE, 18(1), e0280800.https://doi.org/10.1371/journal.pone.0280800
Hewett, T. E., Paterno, M. V., & Myer, G. D. (2002). Strategies for enhancing proprioception and neuromuscular control of the knee: Clinical Orthopaedics and Related Research, 402, 76–94. https://doi.org/10.1097/00003086-200209000-00008
Hewett, T. E., Myer, G. D., & Ford, K. R. (2004). Decrease in neuromuscular control about the knee with maturation in female athletes: The Journal of Bone and Joint Surgery-American Volume, 86(8), 1601–1608. https://doi.org/10.2106/00004623-200408000-00001
Huegel, M., Meister, K., Rolle, G., Indelicato, P.A., Hartzel, J., (1999). The influence of rotational alignment of the lower extremity on noncontact injuries to the ACL in the female athlete. Orthopedic Transactions. J. Bone Joint Surg. 22, 429
Kızılgöz, V., Sivrioğlu, A. K., Ulusoy, G. R., Aydın, H., Karayol, S. S., & Menderes, U. (2018). Analysis of the risk factors for anterior cruciate ligament injury: An investigation of structural tendencies. Clinical Imaging, 50, 20–30. https://doi.org/10.1016/j.clinimag.2017.12.004
Mattu, A. T., Ghali, B., Linton, V., Zheng, A., & Pike, I. (2022). Prevention of non-contact anterior cruciate ligament injuries among youth female athletes: An umbrella review. International Journal of Environmental Research and Public Health, 19(8), 4648. https://doi.org/10.3390/ijerph19084648
Medina, J. M., Valovich McLeod, T. C., Howell, S. K., & Kingma, J. J. (2008). Timing of neuromuscular activation of the quadriceps and hamstrings prior to landing in high school male athletes, female athletes, and female non-athletes. Journal of Electromyography and Kinesiology, 18(4), 591–597. https://doi.org/10.1016/j.jelekin.2006.11.009
McQuilliamm, S., Clark, D., Erskine, R., Brownlee, T. (2022): Mind the gap! A survey comparing current strength training methods used in men’s versus women’s first team and academy soccer, Science and Medicine in Football, https://doi.org/10.1080/24733938.2022.2070267
Orishimo, K. F., Kremenic, I. J., Pappas, E., Hagins, M., & Liederbach, M. (2009). Comparison of landing biomechanics between male and female professional dancers. The American Journal of Sports Medicine, 37(11), 2187–2193. https://doi.org/10.1177/0363546509339365
Wild, C. Y., Steele, J. R., & Munro, B. J. (2013). Musculoskeletal and estrogen changes during the adolescent growth spurt in girls. Medicine and Science in Sports and Exercise, 45(1), 138–145. https://doi.org/10.1249/MSS.0b013e31826a507e
Wild, C. Y., Munro, B. J., & Steele, J. R. (2017). Higher anterior knee laxity influences the landing biomechanics displayed by pubescent girls. Journal of Sports Sciences, 35(2), 159–165. https://doi.org/10.1080/02640414.2016.1159715
ABOUT THE AUTHOR
In 2015 Emily opened Relentless Athletics to build a community for female athletes while educating their parents and coaches on the necessity of strength training and sports nutrition to optimize sports performance and reduce injury risks in the female athlete population.
Emily holds a M.S. in Exercise Physiology from Temple University and a B.S. in Biological Sciences from Drexel University. She is currently pursuing her Ph.D. at Concordia University St. Paul with a research focus on female athletes & the relationship between strength training frequency, ACL injury rates, and menstrual cycle irregularities (RED-s). Through this education, Emily values her ability to coach athletes and develop strength coaches with a perspective that is grounded in biochemistry and human physiology.
In 2020, Emily was an Adjunct at Temple University, instructing her own course on the current research behind female athlete development. Additionally, Emily has worked as a consultant in developing health education curriculums at the high school level.
Emily is passionate about developing young female athletes from middle school to college, assisting in ACL-R rehab, and developing more female strength coaches within the Relentless family while working on her Ph.D.
When she isn’t on the coaching floor or working in her office, she is at home with her husband Jarrod and their daughter Maya Rose, and, of course, their dog Milo (who has become the mascot of Relentless)!!
