ACL INJURIES IN WOMEN’S SPORT
With the AFLW season well underway for another year the topic of ACL injuries once again is at the forefront of many discussions. ACL injuries are increasingly common in female athletes with rates 6.2 and 9.2 times higher in the women's first two seasons compared with the men's AFL across the same years. The season tally is currently siting at 12 ACL injuries at round 7, more than 1 ACL injury each round.
The 2020 AFLW injury report stated that “ACL injuries exhibited the highest incidence and prevalence of all injury categories, with an incidence rate of 7.47 new injuries per 1000 player hours in the 2020 AFLW season. This sits well above the incidence observed in the 2019 AFL competition (0.70 ACL injuries per 1000 player hours)”.
As a comparison, the injury prevalence (per 1000 playing hours) of ACL injuries in the AFLW 2020 (7.47) was higher than the prevalence of hamstring injuries in the AFL men’s comp in 2019 (7.35).
With all this talk about ACL injuries, I have put together a brief crash course.
WHAT IS AN ACL ?
ACL = Anterior Cruciate Ligament, an important stabiliser of the knee joint.
WHY ARE ACL INJURIES IMPORTANT?
- ACL injuries often require surgery and at least 9-12 months of intensive rehabilitation to return to contact sport.
- Will miss one or more seasons.
- Less than 50% of athletes are able to regain their pre injury level of performance (Dunn et al, 2010).
- Fewer injuries are strongly correlated with team success (Eirale et al, 2013).
HOW DO ACL INJURIES OCCUR?
70-80% of ACL injuries in females occur in non-contact situations, changing direction and decelerating or landing on one leg (AFL, 2019).
They occur in positions of “dynamic knee valgus”.
WHY ARE ACL INJURIES MORE COMMON IN FEMALE ATHLETES?
Prior to puberty, ACL injuries are relatively rare and no sex-related differences in ACL ruptures are observed in pre-pubertal athletes (Hewett et al. 2016).
Females and males demonstrate important anatomical, hormonal, and neuromuscular factor differences after the onset of puberty which potentially influences the discrepancy in ACL injury rates between the sexes after puberty (Hewett et al. 2016).
After the onset of puberty, the sexes differ significantly in hormone levels. It has been theorised that the menstrual cycle may be associated with increased knee laxity and ACL injury. Studies indicate that after the onset of puberty, females have significantly higher generalized joint laxity compared to males. The associations between laxity and hormones, coupled with increased generalized joint laxity may contribute to the increased risk of ACL injury in female athletes after puberty. (Hewett et al. 2016).
Post-pubertal females have greater landing forces and force loading rates. Females may rely on higher activations of quadriceps muscles relative to hamstrings muscles. Post-pubertal females also demonstrate altered hip recruitment strategies for controlling landing. A large systematic review demonstrated that males and females differ in trunk and hip neuromuscular control and biomechanics in all planes of motion (sagittal, coronal, and transverse) (Hewett et al. 2016).
Compared to females, males experience increases in power, strength and coordination (neuromuscular spurt) coincident with the hormonal changes that accompany puberty (Hewett et al. 2016).
CAN ACL INJURY RISK BE REDUCED?
In contrast to anatomic risk factors, neuromuscular and biomechanical deficits can be addressed with intervention strategies. Core body control and lower extremity proprioception are modifiable risk factors and are important for adapting to perturbations during sports tasks. Decreased ability to control trunk movements after rapid perturbations, is a highly sensitive for predictor of knee, ligament and ACL injury (Hewett et al. 2016)
Injury prevention programs have been shown to reduce non-contact ACL injury by 67% percent in female athletes (Webster & Hewitt, 2018).
The most effective ACL injury prevention programs include:
- Preseason and in-season training
- Completion three times a week
- Balance training
- Jumping & landing of increasing difficulty
- Athlete feedback and athlete & coach education on avoiding high risk knee positions and the use of safe landing and deceleration techniques.
(Petushek et al, 2018; Voskanian, 2013)
An example of an injury prevention program can be found here.
If you have experienced an ACL injury or would like to discuss a strengthening or injury prevention program, please contact us.