Literature review
Female athletes exhibit a higher incidence of ankle injuries and are more susceptible to ACL injuries than males. The risk factors and mechanisms for these injuries vary between genders. For example, weaker lower extremity muscle strength is a significant risk factor for ACL injuries in female athletes. ACL injuries in female athletes have been described as an "epidemic" in the UK.
Sports medical experts like Dr. Kryger also pointed out various "nature" and "nurture" factors contributing to the higher risk of ACL injuries in women. These include body shape, hip width, menstrual cycle, lack of access to quality training facilities, and inadequate injury prevention training. Football injuries, in particular, account for nearly half of all ACL reconstructions and about one-third of all playing time lost due to injury. Prominent players like England"s Leah Williamson and Beth Mead have suffered ACL tears, significantly impacting major tournaments like the Women's World Cup. Studies suggest that women are six times more likely to suffer ACL injuries compared to men, and 25% less likely to return to the sport post-recovery.
Fundamentally there are biological factors such as biomechanical differences and anatomical & and hormonal factors that influence higher indices of ACL tears in female athletes. Females tend to have greater knee abduction and extension during sports activities. They also exhibit differences in muscle usage, with a tendency towards quadriceps dominance, which may contribute to the higher incidence of ACL tears. Females develop greater knee joint laxity than males, which is a strong predictor of ACL injury risk. This laxity, influenced by genetics, hormone profiles, and anatomy, increases during puberty and contributes to higher-risk biomechanics.
Emmonds, S., Heyward, O. & Jones, B. The Challenge of Applying and Undertaking Research in Female Sport. Sports Med - Open 5, 51 (2019). Emmonds, S. et al found evidence to suggest that female athletes are often underrepresented in sports performance literature, leading to a reliance on scientific investigations conducted with male athletes.
This underrepresentation is evident in searches related to injury and sports like rugby or football, where significantly fewer articles focus on female athletes. Only about 35% of participants in studies published in the British Journal of Sports Medicine are female. The concern arises from applying evidence derived from male athletes to females, ignoring the well-known biological differences between the sexes.
Comstock, R.D., Fields, S.K. The Eternally Wounded Athlete: How Medical Professionals and Sports Injury Researchers Have Limited Female Athletes’ Sport Participation and Biased the Interpretation of Sports Injury Research. Curr Epidemiol Rep 7, 327–333 (2020). Comstock, R.D. & Fields, S.K. found that there is implicit gender bias has influenced the sports medicine sector in terms of sports injury research efforts, clinical practices, and policy decisions. resulting in the exclusion and marginalisation of female athletes.
Sports and Exercise Medicine (SEM) has an inherent gender bias, that has unconsciously contributed to the medical reasoning that females are weaker than males and cannot participate in vigorous physical activity. This has also influenced the sports medicine sector in terms of sports injury research efforts, clinical practices, and policy decisions resulting in the exclusion and marginalisation of female athletes.
The perception that anterior crucial ligament (ACL) injuries primarily afflict young female athletes has impacted the sports medicine domain, hindering both male and female athletes from fully capitalising on potential advancements in research and clinical practices.
Lebel K, Mumcu C, Pegoraro A, LaVoi NM, Lough N and Antunovic D (2021) Re-thinking Women"s Sport Research: Looking in the Mirror and Reflecting Forward. Front. Sports Act. Living 3:746441. doi: 10.3389/fspor.2021.746441. A paper by Lebel K et al. offers a new perspective for women’s sports research which opposes the narrative and paradigms. In addition to this, it aims to highlight the diversity and complexity of female athletes and their participation in sports.
This paper calls for a need to close the gap between academic research and industry practice in women’s sports. Evidence suggests that there is a disconnect between current research and practical applications thus making the current research less influential in terms of decision making. Collaboration is advised to integrate insights from academia and industry to enhance the impact of research. Similar, to the earlier study, the article highlights academia’s role in perpetuating gender biases in sports. Additionally, it recognises the widespread bias towards men’s sports in academic literature and curricula, and the underrepresentation of women in sport management programs, urging for more balanced and inclusive academic practices.
Female athletes, particularly in high school, experience a higher overall injury rate compared to males. This is especially true for knee and lower extremity injuries. Females tend to suffer more from complete ligament sprains, predominantly in the knee, while males are more prone to fractures and dislocations. Many of these injuries in females result in medical disqualifications from the season.
Erin M. Hanlon and Cynthia A. BIR real-time head acceleration measurement in girls’ youth football. Hanlon & Bir et al., primarily focuses on measuring head acceleration during girls' youth football games. The researchers observed 47 header and 20 non-header impacts using a wireless head acceleration measurement device. The findings showed that the highest peak angular acceleration occurred in a non-header event also known as a goalpost collision, while most header impacts were below the injury tolerance levels for linear head acceleration. However, three heading events and one goalpost collision exceeded the concussion tolerance values for angular acceleration, although no concussions were diagnosed during the study. The study highlights that real-time head accelerations during football play can exceed those measured in laboratory settings.
Linear acceleration in direct head contact across impact type, player position, and playing scenario in collegiate women's football players
This cross-study investigated the frequency and magnitude of direct head impacts in collegiate women’s football players across impact type, player position, and game or practice scenario. Results suggested that non-header impacts, like head-to-head collisions and unintentional deflections, resulted in higher mean linear accelerations compared to purposeful headers such as shots, clears, and passes. However, non-header impacts occurred less frequently. The study revealed no significant differences in linear acceleration across player positions or between games and practices. This indicates that while non-header impacts are more severe, the overall exposure to potential injury in women's collegiate football is predominantly driven by the frequency of purposeful headers.
Hallén A, Tomás R, Ekstrand J, et al UEFA women’s elite club injury study: a prospective study on 1527 injuries over four consecutive seasons 2018/2019 to 2021/2022 reveals thigh muscle injuries to be most common and ACL injuries most burdensome British Journal of Sports Medicine 2024;58:128-136. Hallén A, Tomás R, Ekstrand J, et al researched the injury epidemiology among women’s elite football players. The study recorded 1527 injuries in 463 players with an injury incidence of 6.7 injuries per 1000 hours. The incidence was nearly fourfold higher during matches compared to training. The most frequent injuries were at the knee, thigh, and ankle. The most common types of injuries were joint/ligament injuries, muscle injuries, and contusions/haematomas. In contrast to the previous studies this research suggests ACL injuries account for only 2% of injuries in women's football, while hamstring injuries are the most common at 12%. The incidence of ACL injuries in women's football is 0.1 per 1000 hours of play. Elite women's teams can expect about 0.7 ACL injuries per season and knee ligament injury rates during the 2022/2023 season were 44% for men in comparison to 36% for women. Furthermore, the study discovered that elite female footballers lose an average of 81 days to ligament injuries, compared to 40 days for their male counterparts.
Nonetheless, the evidence suggested that ACL injuries had a high injury burden due to their potential negative long-term consequences. Elite female footballers lose an average of 81 days to ligament injuries, compared to 40 days for their male footballers. However it is the significant difference in recovery time contributing to the perception that ACL injuries are a crisis for women. In reality, the rate of ACL injuries is nearly the same for both men and women.
Player and game characteristics and head impacts in female youth ice hockey players Nick Reed, PhD, MScOT, OT Reg*†‡; Tim Taha, PhD§; Richard Greenwald, PhD||¶; Michelle Keightley, PhD, CPsych†. The study revealed that in female youth ice hockey, head impacts occur despite the absence of intentional body checking. Key factors influencing the frequency and severity of these impacts include higher body mass index (BMI), older age, playing in the forward position, and more time spent on the ice. The study found that these factors led to increased linear and rotational acceleration of head impacts.
Biomechanics of head impacts associated with diagnosed concussion in female collegiate ice hockey players Bethany J. Wilcox a,n, Jonathan G. Beckwith b, Richard M. Greenwald b,c, Neha P. Raukar d, Jeffrey J. Chu b, Thomas W. McAllister e, Laura A. Flashman f, Arthur C. Maerlender g, Ann-Christine Duhaime h, Joseph J. Crisco. A study evaluating head impact data from female ice hockey players found that head impact exposure, both in frequency and magnitude, was greater on days when concussions were diagnosed compared to days without. The study's key findings were that female athletes may have a different biomechanical tolerance to concussion injuries compared to males. Studies in concussion epidemiology studies have shown higher rates of concussion incidences, recurrent concussions, and a longer duration of symptom resolution in females. The mechanisms of concussions also differ between genders, with females more often experiencing player-to-playing surface or player-to-ball contact, while males frequently sustain concussions from player-to-player contact.
Head impact exposure from match participation in women’s rugby league over one season of domestic competition. The study on head impact exposure in women's rugby league revealed a high frequency of head impacts, with a total of 1659 impacts greater than 10g recorded over nine matches. Most impacts occurred on the side of the head and were more frequent in the second half of matches, indicating increased risk as the game progressed. Comparatively, the rate of head impacts in women’s rugby league was lower than in men’s rugby union but higher than in junior rugby leagues and other contact sports like youth ice hockey and collegiate women’s football. The study also noted a significant concussion incidence rate, emphasising the importance of awareness and protective measures in the sport.
