As the alarming rate of ACL injuries among female footballers continues to rise compared to that of their male counterparts, it is the entire footballing world's duty to protect future generations of female athletes.
An Anterior Cruciate Ligament (ACL) injury occurs when ligaments in the knee connecting the femur and tibia are torn or ruptured. It is one of the most severe injuries in field sport: a complete rupture of the ACL results in young athletes’ requiring complete reconstructive surgery if they hope to return to their best, and total recovery time typically takes between six and twelve months1.
Repeated movements specific to those demanded by football pose serious risk of damaging an ACL. Quick changes of direction, decelerations and forceful collisions all increase a player’s exposure to ACL risk, and many injuries happen directly as a result of landing a jump incorrectly2.
But what is most concerning for many players, coaches and parents is the frequency with which women are suffering ACL problems. In the season gone by, one that followed the monumental and historic Women’s Euros, a staggering number of high profile athletes had their seasons cut short by injury. Arsenal and England duo Beth Mead, Player of the Tournament at the Euros, and Leah Williamson, the England Captain, both suffered from a ruptured ACL in November and April respectively. For the national side, this means the team will be without their number one and number two Players of the Year for this summer’s Women’s World Cup. Since then, Arsenal forward Vivianne Miedema and defender Laura Wienroither’s names have been added to the same list, prompting coach Jonas Eidenvall’s “internal reflection” to investigate the cause of ACL injuries within the club and his call for “external cooperation” across football bodies to help put an end to what he deems a “tragedy” in the women’s game3.
Eidenvall’s concerns mostly lie with the density of the football calendar. Players like Mead and Williamson, who went all the way to the final in the Euros with England, were then expected to compete in the Women’s Super League as well as the Women’s UEFA Champions League campaign. It doesn’t stop there. Tim Stillman, a women’s football journalist, reported that just days after the end of the upcoming World Cup, Arsenal Women will be involved in qualifiers for next season’s Champions League. Stillman highlights Eidenvall’s plea to important stakeholders UEFA and FIFA to organise tournaments in such a way that allows women, who are three to six times more likely than men to incur ACL injuries, to manage load and decrease injury risk.
But it’s more than just changing the football calendar that needs to be done.
Female athletes have biologically three to six times more ACL risk than male athletes4. Several studies highlight the effect of hormonal influences on ligament laxity and a higher prevalence for valgus (knock knee) lower limb alignment. These specific differences between biological women and men cause women footballers to suffer ACL injuries predominantly from “rapid deceleration” when moving horizontally, “combined with single leg loading and a change of direction” as opposed to injuries associated with landing a jump5.
"Female athletes have biologically three to six times more ACL risk than male athletes"
However, there is a worrying belief that bias towards male athletes in sporting environments plays a significant role in the number of ACL injuries in women and, as women’s football grows in popularity and participation, puts future generations of female athletes and girls in danger.
There are innumerable ways in which girls and women are at a disadvantage when it comes to preventing ACL injuries. For example, it has been pointed out that women footballers and girls train and compete wearing football boots designed for men. According to Dr Kat Okholm Kryger, a senior lecturer in sports rehabilitation at St Mary's University, Twickenham, boots are designed to provide men a certain amount of traction based on their power output6. Therefore, traction in women’s boots is higher relative to their needs, which puts them at greater risk.
The most stark differences occur as a result of the underfunding of women’s football at all levels compared to boys’ and men’s football. The pitches on which women train and compete are either not well kept, or first-use of them is reserved for male teams. The result is pitch conditions which are dry and uneven, increasing injury risk in general.
Perhaps the most significant disadvantage, however, is the difference in quality and accessibility of sporting advice and education at the developmental stage between boys and girls. There is strong evidence that points to injury prevention programmes reducing ACL injury risk by half, and by two thirds in women sustaining non-contact ACL injuries7. However, access to high quality coaches capable of implementing and incorporating such programmes into training is massively skewed towards boys’ football, leaving girls unable to develop the biomechanical, neuromuscular control, and strength training techniques required to keep safe from ACL injuries. The lack of accessibility to such programmes for girls is likely a significant contributor to the prevalence of ACL injuries in the current generation of women footballers.
If football wants to protect women against ACL injuries, it is imperative that scientifically backed training programs are made accessible to girls’ teams as quickly as possible.
The most effective prevention programmes involve plyometric training combined with biomechanical analysis and technique training8. Plyometrics include exercises that use movements at high speed and significant force to build muscle power. High-intensity plyometric jumping movements allow athletes to train for proper technique and body mechanics. Choosing exercises that place safe levels of valgus stress on athletes induce the adaptations required to correct for neuromuscular imbalances in biological females. This better prepares athletes for sports involving high-intensity changes of direction and trains them to better position themselves to reduce high loads on the ACL. Further, coaches are encouraged to analyse video footage of ACL injury occurrences and incorporate instructions for good technique into their sessions. Such instructions may include landing with a bent knee, decelerating before changing directions or informing athletes to stay on their toes. By developing better technique and neuromuscular control at young ages, girls have less risk of non-contact ACL injuries at later stages of their career.
Another factor of consideration is recovery after ACL reconstruction. The rate of recurred ACL injury can be as high as 32%1. While it is unfortunately the case that the current generation of women footballers are likely too far gone to benefit from prevention programmes, a safe and well-monitored return to sport may reduce the risk of a second ACL-related injury. Load monitoring is one way of ensuring a proper return to sport.
While load placed on an athlete during plyometric and strength exercises in a gym is more easy for coaches to assess and monitor, it can be difficult to assess the load on their players after a return to training sessions on the pitch. The use of GPS tracking data gives coaches an understanding of the running load for a specific player recovering from ACL injury in a session. Accessible GPS units have the potential to significantly increase teams’ awareness and knowledge of the fitness levels and recovery progress of their players. Total distance, high-speed running and top running speed may indicate how far along a player is in recovery.
"GPS units have the potential to significantly increase teams’ awareness and knowledge of the fitness levels and recovery progress of their players"
However, acceleration and deceleration data may provide the greatest insight into the amount of load placed on a player’s ACL. Decelerations, in particular, are a significant contributor to injury risk, as mentioned previously. Coaches may choose to involve recovering players in sessions that have historically fewer accelerations and decelerations, based on the data they have collected in the past. By monitoring a player’s load data obtained via GPS information, both the player and coach can track recovery and understand which sessions might cause the greatest stress on the ACL.
As women’s football grows in popularity and participation, the number of girls playing football will rise accordingly. If football’s stakeholders expect the very best female players to be available to participate across major tournaments, season after season, then the appropriate efforts and investments must be made now to ensure that girls are able to train and compete safely.