A FIFA-funded study at Kingston University will investigate whether hormonal fluctuations during the menstrual cycle contribute to the increasing incidence of anterior cruciate ligament (ACL) injuries in female footballers.
The study follows a series of high-profile ACL injuries, including those sustained by Arsenal’s Beth Mead, Manchester City’s Vivianne Miedema, and Chelsea’s Sam Kerr. Kerr, an Australian international, has been sidelined for 15 months due to a ruptured ACL.
Led by PhD student Blake Rivers and a team of sports science researchers, the year-long investigation will analyze blood samples from elite and amateur footballers to assess hormone concentrations across the menstrual cycle.
"We want to examine whether athletes may be more predisposed to injuries because of the functional changes in terms of their anatomy and physiology during the menstrual cycle," said Simon Augustus, Senior Lecturer in Sport Biomechanics
The study will monitor circulating estrogen and progesterone levels—hormones previously associated with increased ligament laxity and reduced neuromuscular control—and correlate them with physical performance data collected across the menstrual cycle.
"We know hormones fluctuate during different phases of the cycle, but we don't yet know how much of an influence that may have on the risk of injury," Augustus said.
Beginning in June, the research team will recruit footballers from London clubs, including Chelsea and Fulham, for serial testing at the Kingston University campus. These sessions will involve blood draws and performance assessments.
Researchers will also examine mechanisms commonly associated with ACL injuries, such as landing biomechanics following headers and rapid changes in direction, to assess whether these factors are modulated by hormonal variation.
"We know some injuries are unavoidable, but we're attempting to help those individuals who injure their ACL outside of impact actions -- those are the ones where we might have more chance to intervene and prevent them from taking place by utilising strength training or tweaking technique."
"There are so many different factors involved with ACL injuries. We are starting to research this from an individual approach and look at an athlete's whole profile and putting protocols in place to reduce risk."
The researchers aim to generate evidence that could inform individualized training or rehabilitation programs, including potential adjustments to training loads based on menstrual cycle phase.